The purpose of this article is to ensure that development is
outside of hazardous areas and creates no new hazards, and that the
form of development and its infrastructure is compatible in design
and engineering with the balance of this chapter.
A.
Permits. Construction permits shall be required pursuant to Table
6.1, Construction Permits. Applications shall be made by the property
owner or owner's authorized representative (permittee), who shall
represent all parties of interest. The County may refuse to accept
a permit application when relevant information is missing or there
is no written evidence of the ownership of the property surface rights
provided in the application. The applicant shall be notified when
information is missing from the application.
B.
Department review. All permits required for any development shall
be approved by the designated County review department(s) listed in
Table 6.1, Construction Permits.
C.
Expirations. Every permit issued by the County under the provisions
of this article shall expire by limitation and become null and void
if the construction or work authorized by such permit is not commenced
within 60 days from the date of such permit or as specified in Table
6.1, Construction Permits. The permit shall also expire if the construction
or work authorized by such permit is suspended or abandoned any time
after the work is commenced for a period of 90 days. After 90 days,
a new permit shall be obtained and the fee shall be 1/2 of the original
permit; and provided, further, that such suspension or abandonment
has not exceeded 180 days. After 180 days of inactivity, a new permit
shall be obtained.
(1)
Any resident holding a current permit may apply for an extension
of time within which work may commence under that permit when the
permittee is unable to commence work within the time required by this
section for good and satisfactory reasons. The County may extend the
time for action by the permittee for a period not exceeding 90 days
on written request by the permittee showing that circumstances beyond
the control of the permittee have prevented action from being taken.
No permit shall be extended more than once.
D.
Suspension or revocation. The County may, in writing, suspend or
revoke a permit issued under the provision of this article whenever
the permit is issued in error or on the basis of incorrect information
supplied, or in violation of an ordinance or regulation or any provisions
of this article.
Table 6.1 Construction Permits
| ||||
---|---|---|---|---|
Permit Type
|
County Review Department
|
Review Time
|
Expiration
|
Inspection
|
Access permit
|
Engineering Services
|
10 working days after acceptance of complete application.
|
Within 6 months of issuance.
|
Engineering Services
|
For access permit specifications, see § 350-601E
| ||||
Floodplain development permit
|
Flood Commission
|
30 working days after acceptance of complete application.
|
Within 1 year of issuance.
|
Building Services
|
For development permit specifications, see § 350-601G
| ||||
Grading permit
|
Engineering Services and Flood Commission
|
15 working days after acceptance of complete application.
|
Within 180 days of inactivity and per § 350-602D below.
|
Engineering Services
|
For grading permit specifications, see § 350-601H
|
E.
Access permits. Applications shall be made pursuant to Table 6.1,
Construction Permits.
(1)
Permit application forms for nonresidential or multifamily parcels.
Completed permit application forms shall be submitted to the Engineering
Services Department (ESD). The permit application shall include the
following:
(a)
Thoroughfare and driveway plan and profile; drainage plan of
the site showing impact to public right-of-way, development, wildlife
corridors and the adjacent parcels; alternative site design may also
meet this requirement if design strategies include integrated features;
(b)
Map and letters delineating utility locations before and after
the construction of access in and along the thoroughfare;
(c)
Subdivision, zoning or development plan, if applicable;
(d)
Property map indicating other access and adjacent public roads
and thoroughfares;
(e)
Proposed access design;
(f)
The intended use of the property;
(g)
Site threshold analysis, if required;
(h)
A professional engineer, licensed in the state of New Mexico,
prepared and certified traffic control plan, if applicable, in conformance
with the Manual on Uniform Traffic Control Devices for Thoroughfares
and Highways, as amended;
(i)
Grading permit application, if required; and
(j)
Erosion control measures or alternative stormwater control measures
(SCM).
(2)
Permit application forms for a single-family or common driveway
parcel. Completed permit application forms shall be submitted to the
ESD. The permit application shall include the following:
(a)
Thoroughfare and driveway plan and profile; drainage plan of
the site showing impact to public right-of-way, development, and the
adjacent parcels;
(b)
Map and letters delineating utility locations before and after
the construction of access in and along the thoroughfare;
(c)
Property map indicating other access and adjacent public roads
and thoroughfares;
(d)
Grading permit application, if required; and
(e)
Erosion control measures, or alternative stormwater control
measures (SCM) if required.
(3)
Application review procedures. The review period begins with
the acceptance of a complete permit application by the appropriate
County-designated representative.
(a)
Transmittal of a completed permit, approved by the ESD, or transmittal
of a denied application constitutes action on the permit application.
(b)
If the ESD denies an application, the ESD shall provide the
applicant a copy of the application marked "denied," along with any
attachments and a written explanation for the decision.
(c)
If the ESD approves an application permit, the permit shall
be prepared and transmitted to the applicant along with any additional
terms and conditions established by the ESD. If the permittee does
not agree to all terms and conditions of the permit, the permit shall
be deemed denied.
(d)
The permitted access shall be completed in accordance with the
terms and conditions of the permit prior to being used for vehicular
access. In accepting the permit, the permittee agrees to all terms
and conditions of the permit. Should the permittee choose to appeal
a denied application, or the terms and conditions of a permit, the
appeal shall be filed within 30 days of the date of transmittal of
the notice of denial of transmittal of the permit.
(4)
Construction requirements.
(a)
The permittee shall notify the ESD of the pending construction
at least five working days prior to any construction in a County right-of-way.
(b)
Work shall be performed by an appropriately licensed contractor
and insured in the State of New Mexico.
(c)
The ESD may inspect the access during construction and upon
completion of construction to ensure that all terms and conditions
of the permit are met. Property required for access improvements may
be required to be dedicated, and if so shall be dedicated without
cost to the public.
(d)
The access construction as required by the terms and conditions
of the permit shall be completed at the expense of the permittee.
The County may bill the permittee for direct costs and labor provided
by the County for the installation and relocation of all traffic control
devices within the public right-of-way directly related to the use
of the permitted access. Where construction of access requires the
reconstruction of the existing thoroughfare, the County shall require
the contractor or permittee to post a bond in an amount sufficient
to ensure completion of the work.
(e)
The hours of operation/work on or immediately adjacent to the
thoroughfare may be restricted due to peak-hour traffic demands and
other pertinent thoroughfare operating restrictions. Generally, the
hours of operation/work shall be limited to daylight hours, Monday
through Friday.
(f)
A copy of the permit shall be available for review at the construction
site. If necessary, minor changes and additions shall be ordered by
the County to meet unanticipated site conditions and noted on the
permit documents.
(5)
Illegal access to the thoroughfare. The County may install barriers
across or remove any access that provides direct access to a County
road that is constructed without an access permit or used in violation
of this article or permit terms and conditions.
(6)
Improvements to legal access. The permittee may make physical improvements to an access with the permission of the County. The applicant shall use the access permit pursuant to § 350-601E. Review and processing of the permit application will be in accordance with this article.
(7)
Revocations. Where a property is being redeveloped, reconstructed,
or its basic vehicular usage changed, the owner shall apply for a
new access permit and reconstruct the driveways to comply with this
article.
F.
Erosion control best management practices.
(1)
Description. Best practice will integrate project features that
emphasize protection of watershed function through replication of
predevelopment runoff patterns (rate, volume, duration).
(2)
Method. Best practice will integrate construction methods and
engineering practices. Best practice will include natural features
of the landscape and engineered solutions (e.g., infiltration and
water storage) to treat, manage, and control stormwater on-site to
reduce erosion. Best practices should be coordinated with ESD and
CDD staff.
[Amended 11-14-2017 by Ord. No. 294-2017]
G.
Floodplain development permit. A floodplain development permit may be required, in accordance with National Flood Insurance Program (NFIP), if the proposed development is all or partially located within a FEMA special flood hazard area as defined in § 350-604. The Flood Commission Director shall determine if a floodplain development permit is required and shall appoint a Floodplain Administrator to review. When appropriate, a floodplain development permit shall be issued.
[Amended 12-8-2020 by Ord. No. 317-2020]
(1)
Application review procedures. The review period begins with
the acceptance of a complete permit application by the Floodplain
Administrator or designee. A record of all information shall be maintained.
Approval or denial of a floodplain development permit by the Floodplain
Administrator shall be based on all of the provisions of this article
and the following relevant factors:
(a)
Plans in duplicate drawn to scale showing the location.
(b)
Dimensions.
(c)
Elevation of proposed landscape alterations.
(d)
Existing and proposed structures, including the placement of
manufactured homes.
(e)
Location of the foregoing in relation to areas of special flood
hazard.
(f)
Elevation (in relation to mean sea level) of the lowest floor
(including basement) of all new and substantially improved structures.
(g)
Elevation in relation to mean sea level to which any nonresidential
structure shall be floodproofed.
(h)
A certificate from a registered professional engineer or surveyor that the nonresidential floodproofed structure shall meet the floodproofing criteria of § 350-604G(2).
(i)
Description of the extent to which any watercourse or natural
drainage will be altered or relocated as a result of proposed development
or description of alternative integrated methods considering natural
and built drainage systems.
(2)
Application review procedures. The review period begins with
the acceptance of a complete permit application by the Floodplain
Administrator or designee. A record of all information shall be maintained.
Approval or denial of a development permit by the Floodplain Administrator
shall be based on all of the provisions of this article and the following
relevant factors:
(a)
The danger to life and property due to flooding or erosion damage.
(b)
The susceptibility of the proposed facility and its contents
to flood damage and the effect of such damage on the individual owner.
(c)
The danger that material may be swept onto other lands to the
injury of others.
(d)
The compatibility of the proposed use with existing and anticipated
development.
(e)
The safety of access to the property in times of flood for ordinary
and emergency vehicles.
(f)
The costs of providing governmental services during and after
flood conditions, including maintenance and repair of thoroughfares
and bridges, and public utilities and facilities such as sewer, gas,
electrical and water systems.
(g)
The expected heights, velocity, duration, rate of rise and sediment
transport of the floodwaters and the effects of wave action, if applicable,
expected at the site.
(h)
The necessity to the facility of a waterfront location, where
applicable.
(i)
The availability of alternative locations, not subject to flooding
or erosion damage, for the proposed use.
(j)
The relationship of the proposed use to the Comprehensive Plan,
all other relevant drainage plans and master plans for that area.
(3)
Grading and predevelopment best management practices.
(a)
Description. Best practice will preserve existing natural features
to reduce cost associated with erosion, revegetation, and dust control.
(b)
Methods. Best practice will include natural drainage, topography,
rock outcroppings, and native plant areas which can be preserved,
and serve as detention areas to promote on-site benefits of water
resources. Best practices should be coordinated with EDS and CDD staff.
[Amended 11-14-2017 by Ord. No. 294-2017]
H.
Grading permit. Any person required under § 350-605 to submit a grading permit shall apply to the County prior to the issuance of a building or construction permit by an appropriately licensed contractor in the State of New Mexico and shall meet the minimum requirements of this article, as determined by ESD. The application will be signed by the owner of the property where the work is to be performed or by his/her duly authorized representative. The applicant shall ensure that all application data is correct. Any falsification of application data shall invalidate the permit.
(1)
Permit application. A grading permit shall be issued by the
County based on the following:
(a)
Submittals shall be prepared and certified by a New Mexico professional
engineer.
(b)
Grading permits shall be reviewed by the ESD and the Flood Commission
and issued based upon approved final subdivision plats, building or
such other site improvement plans as necessary for development of
the property on which such permit is required.
(c)
Removal of more than 50 cubic yards shall require disclosure
of disposal site.
(d)
On-site processing of material is limited to those used for
preparation or construction of improvements within the site covered
by the grading permit.
(e)
A grading plan shall show drainage control methods and shall control dust and erosion if an erosion control plan is not required per § 350-605D, Erosion control plan (ECP).
(f)
A drainage report, as outlined in § 350-605I, Drainage report, shall be required if one of the following conditions, or other drainage susceptible conditions as determined by ESD or the Flood Commission, apply:
(g)
The grading permit shall only be issued in conjunction with
a complete set of approved construction plans.
(2)
Every application will contain the following information:
(a)
Location, nature and extent of the proposed work and a general
statement as to the intended use of the site.
(b)
The names, addresses and phone numbers of the owner(s) of record
of the property on which the work is to be performed.
(c)
The names, addresses and phone numbers of the persons, contractors,
or organizations that will perform the work and of the person who
will be in effective control of the work.
(d)
For all roads or other excavations where the volume of earth
to be moved exceeds 1,000 cubic yards, a cut and fill map showing
the height of cuts and fills at a maximum of fifty-foot intervals
and at any major breaks in the terrain shall be required.
(e)
Time frame for work to start and to be completed.
(f)
Any additional related information required by the County that
may be reasonably required to carry out the purpose and intent of
this article.
(3)
An application for a grading permit shall include a topographic
and boundary survey and grading plan, prepared and certified by a
NMPE, with elevation contours shown at not more than two-foot intervals
on slopes up to 30% and five-foot intervals on slopes greater than
30% that shows:
(a)
Contour mapping shall extend a minimum of 500 feet beyond the
development boundaries;
(b)
Location and finished floor elevation (FFE) of all existing
structures;
(c)
All areas with slopes 0% to 20%, 21% to 30%, and 31% and greater,
differentiated through shading, tone, color or line weight, as well
as vertical and horizontal data;
(d)
A permanent benchmark noted on the plan and approved by the
ESD shall be used in determining the location of improvements within
the development. Both horizontal and vertical datum are required.
A tie to a section corner or other known, accepted and approved monuments
are required;
(e)
All areas to be graded on the site and the final contours to
be achieved by the grading;
(f)
All finished floor or grade elevations;
(g)
The location of temporary erosion structures and methods used,
including staging and stockpile areas, unless an erosion control plan
is included within submittal;
(h)
All pertinent drainage information, including but not limited
to drainage flow arrows, flow rates, volumes, proposed inflow and
outflow points for runoff from the study area showing both the pre-
and post-development conditions;
(i)
All facilities for control and disposition of stormwater runoff;
(j)
Descriptions to include all pertinent information (e.g., size,
slope, material, etc.) of existing irrigation and drainage facilities
and structures shall be submitted, such as ditches, drainageways,
gutters and culverts and shall include all pertinent information such
as size, slope and material;
(k)
Development limits and individual lots, including building envelopes,
footprints, or pads if applicable, rights-of-way, easements, and proposed
thoroughfare improvements;
(l)
One hundred twenty-five percent of the differential runoff between
predevelopment and post-development conditions shall be retained/detained
in ponding areas;
(m)
All significant trees and areas with substantial grass coverage
to be removed;
(n)
A construction schedule when the project will be developed in
phases;
(o)
The location of fencing around the areas to be protected;
(p)
The ratio of horizontal to vertical measurement for cut and
fill slopes;
(q)
The total volume, in cubic yards, of earth to be moved;
(r)
All existing disturbed areas; and
(s)
FEMA flood hazard areas and FIRM information.
(4)
Applicants shall comply with the Environmental Protection Agency
(EPA), the Federal Emergency Management Agency (FEMA), New Mexico
Environment Department (NMED), the United States Army Corps of Engineers
(USACE), Office of the State Engineer (OSE), or as applicable by law.
It is the responsibility of each applicant to determine whether additional
notification or permitting is required.
(5)
Liability insurance required; hold-harmless agreements. General
liability insurance shall be required as a condition for issuance
of a grading permit.
(a)
Procurement and maintenance of such liability insurance policy
shall be the sole responsibility of the applicant.
(b)
Before any grading permit is issued, the applicant shall attach
to the application a copy of a current certificate of insurance as
evidence of general liability and contractual insurance. The minimum
limit of liability shall be $300,000 combined single limit. Such policy
certification shall provide that the insurance cannot be canceled
or the limit of coverage reduced without 30 days' prior written notice
to the County. Failure to provide the insurance certification or failure
to meet the minimum liability insurance requirements will result in
no permit being issued. Should the liability insurance policy expire
or be canceled, the County shall revoke any outstanding grading permit
under such policy.
(c)
The applicant shall be required to enter into a hold-harmless
agreement with the County protecting the County, any of its departments,
agencies, officers, or employees from all cost, injury and damage
incurred by the applicant and from any other injury or damage to any
person or property whatsoever caused by any activity, conduct, or
event arising out of any act authorized by the permit. The County
shall provide the approved form for this hold-harmless agreement.
(6)
Application review procedures. The review period begins with
the acceptance of a complete permit application by the appropriate
County-designated representative.
(a)
The grading permit will be issued by the County upon verification
and approval of the information contained within the permit application.
(b)
The County can refuse to issue any grading permit whenever the
proposed grading is contrary to the provisions of this article.
(c)
If any person does any grading or otherwise disturbs the ground
cover of any property within the County without a grading permit,
he/she shall apply for a grading permit and shall be subject to a
triple permit fee.
(7)
[1]Removing hazardous conditions.
(a)
If the County finds that the grading (either completed or in
progress) is causing a hazard to persons or property, it shall notify
the owner or his authorized representative and require that the hazard
be removed or eliminated as soon as practicable, depending upon the
degree of urgency with the hazard involved. If such action is not
completed within the time limit stated within the notice, the County
may require that reasonable temporary protective measures be provided
in the interim.
(b)
If materials are washed or accumulated upon thoroughfares, lanes
or other public property as a result of improperly controlled grading
of higher or adjacent lands, the County shall notify the owner or
his authorized agent to remove such material and restore the thoroughfares,
lanes or public property to their original condition within 24 hours.
Failure to comply with such notice shall be a violation of this article.
(c)
If the owner fails to comply with such notice as provided in
§ 350-601H(a) or (b) above, the County may authorize the
work to be done by County resources or by contract. A report shall
be prepared for the BOCC covering the actual cost of doing the work.
After notice and an opportunity to be heard, the BOCC may, by resolution,
determine the actual cost of doing the work and declare this amount,
plus the cost of recording the resolution, to be a personal liability
of the owner of the land and a lien on the land, payable within 10
days after adoption of the resolution, and thereafter bearing the
simple annual interest at a rate of 12% until paid. A copy of the
resolution, authenticated by the acknowledgement of the County Clerk,
shall be filed for record in the office of the County Clerk. Notice
of the hearing before the BOCC shall be in writing and delivered in
person or sent by certified mail with return receipt requested to
the owner and to holders of recorded liens on the property. If, after
reasonably diligent efforts, the person to be notified of such hearing
cannot be found, notice may be given by one publication in a newspaper
of general circulation within the County.
(d)
Materials from a grading site that are spilled or deposited
onto public thoroughfares shall be removed by the contractor or permittee
on the same day. Whenever ramps are required to cross County rights-of-way,
approval shall be obtained.
(8)
Responsibilities of landowner or authorized representative.
Under this article, the landowner or his authorized agent will be
responsible for:
(a)
Obtaining a permit, if required, for any grading.
(b)
Obtaining the services of a professional engineer, licensed
to practice in the State of New Mexico.
(c)
All the legal duties, obligations or liabilities incident to
ownership of the property while the work of grading is in progress
or after the completion of the work. Neither the issuance of a permit
nor the compliance with the provisions of this article shall relieve
any person or owner from any responsibility for damages to persons
or property otherwise imposed by law, nor impose any liability upon
the County, or any official of the County, for such damages.
(d)
Installing the appropriate devices, structures, landscaping
and facilities and executing soil stabilization, erosion control,
handling of materials in conjunction with any proposed grading so
as to fulfill the intent and purpose of this article.
(e)
The continued maintenance and repair of all retaining walls,
cribbing, drainage facilities, slopes, landscaping, soil stabilization
and erosion control measures and any other protective devices located
upon his property and constructed pursuant to the permit.
(f)
Applying for a grading permit to coordinate and obtain clearance
from all utilities with a property interest within the boundaries
of the permit. Failure to clear any such utility may result in an
immediate suspension of the grading permit.
(g)
Replacing any surveying and/or property monuments that may be
disturbed during grading operations. Monuments shall be certified
by a professional surveyor, licensed to practice in the State of New
Mexico.
(h)
Notifying New Mexico One Call within 48 hours of start of construction.
(9)
Responsibility and authority of the County. The County, under
the authority of this article, shall be responsible for:
(a)
Reviewing all grading permit applications as submitted under the requirements of § 350-601H above and issuing or denying grading permits within 15 working days.
(b)
Performing or obtaining all the appropriate tests and inspections
to assure that the conditions of the permit and intent and purpose
of this article have been fulfilled. Unforeseen testing requirements
shall be the applicant's responsibility at the time of application.
(c)
Imposing such conditions and specifications on the issuance
and duration of the grading permit as may be reasonably necessary
to cause the work to fulfill the intent and purpose of this article.
These conditions and specifications shall include, but will not be
limited to, the following:
[1]
Interim and permanent soil erosion control and land management
requirements, including provisions for:
[a]
Disturbed soil surface treatments (emulsions, mulches,
seeding, and the like);
[b]
Protective drainage measures for surface drainage
and subsurface water where required;
[c]
Terracing and use of dikes and berms;
[d]
Paving and other miscellaneous related measures;
[e]
Retaining walls; and
[f]
Approved development plans.
[2]
Compaction requirements in cut and fill areas.
[a]
Unstabilized slopes shall be no steeper than 6:1,
unless a structural alternative or some other measures applying professional
engineering standards are provided. Cut or fill for roads shall not
exceed 15 feet in height;
[b]
On-site cut slopes shall not exceed 10 feet in
height. In no case shall the height of the cut exceed the height of
the building;
[c]
On-site fill slopes shall not exceed 15 feet in
height. Retaining wall for fill slopes shall be no greater than 15
feet in height; or
[d]
All cut and fill areas shall be compacted to no
less than 95% as determined by ASTM D1557, modified proctor.
[3]
Working procedures and safety requirements:
[a]
Protective fencing;
[b]
Excavation slope limitations, shoring and bracing
in accordance with OSHA guidelines and procedures;
[c]
Traffic control requirements concerning transportation
of material on public ways;
[d]
Limitations on the amount of area that may be disturbed
by grading operations;
[e]
Work scheduling requirements; and
[f]
Stockpiling and reuse of topsoils.
A.
Sidewalks.
(1)
Sidewalks shall be required along all thoroughfares where the
average lot size of adjacent lots are 1/2 acre or less in size. Sidewalks
shall have a minimum width of four feet and as regulated further by
Table 4.2, Minimum Width of Sidewalk Standards. All sidewalks shall
have a minimum thickness of four inches.
[Amended 11-14-2017 by Ord. No. 294-2017; 12-8-2020 by Ord. No. 317-2020]
(2)
Sidewalks shall be constructed out of concrete or other materials
accepted by ESD and shall be built at the time of thoroughfare construction
unless access is for primary residential lot frontage.
(3)
Thoroughfare lights, power poles, fire hydrants, thoroughfare
signs or other types of obstructions shall not be permitted on the
sidewalks or the designated walkway. If thoroughfare obstructions
are in the way of proposed sidewalks, the obstructions shall be relocated
prior to construction of the sidewalk.
(4)
Table 6.9, Typical Urban Parkways. Sidewalks shall meet the
requirements of the Americans with Disabilities Act.
B.
Thoroughfare design guidelines. If a County design standard does
not exist for a particular project, the New Mexico Department of Transportation
standards, United States Department of Transportation standards, and
the Institute of Transportation Engineers (ITE) Context Sensitive
Solutions (CSS) shall apply.
(1)
The applicant shall provide documentation proving that all roads
to and within a development have unobstructed legal and physical access
to an asphaltic surfaced municipal-, County- or state-maintained road(s).
It is the developer(s) responsibility to construct the legal and physical
access from the development to an asphaltic surfaced municipal-, County-
or state-maintained road(s).
(2)
The width for thoroughfares linking a development intensity
or transect zone development to a County- or state-maintained road
shall be regulated by Table 6.8, Thoroughfare Geometry.
(3)
The width for thoroughfares linking a use zone development to
a County- or state-maintained road shall be regulated by Table 6.8,
Thoroughfare Geometry.
(4)
The layout of principal roads within a development shall be
designed to join to principal existing thoroughfares in adjoining
areas and to serve adjoining areas. The width of the right-of-way
in a development shall be sufficient to ensure that future development
needs will not be limited by narrow rights-of-way, per the Mesilla
Valley and El Paso MPOs.
(5)
Centerlines of offset thoroughfares entering onto collector
or arterial thoroughfares shall not be less than 400 feet apart.
(6)
All roads shall be provided with adequate grades, lines-of-sight
and drainage, including the conveyance of collected runoff, and culverts
or dip sections for the lateral passage of flows. Easements external
to a thoroughfare right-of-way section may be used for the conveyance
and storage of storm runoff and utilities if water intrusion onto
the right-of-way is mitigated via subsurface drainage.
(7)
Thoroughfares shall intersect as nearly as possible at right
angles, and in no case shall thoroughfares intersect at angles of
less than 75° for local thoroughfares and 90° for collector
and arterial thoroughfares.
(8)
Thoroughfares should connect to other thoroughfares when possible,
forming a network. Dead-end thoroughfares shall terminate in a cul-de-sac
having a minimum radius of 50 feet for residential uses and 80 feet
for nonresidential uses. Phased development or construction shall
be provided with temporary turnaround easements with fifty-foot radii
for residential and eighty-foot radii for nonresidential uses as necessary
at the end of each phase, constructed with base course and prime coat,
and may be vacated upon extension of the road within a subsequent
phase. Turnarounds, in phased development, are not required on thoroughfares
less than 150 feet in length.
[Amended 11-14-2017 by Ord. No. 294-2017]
(9)
All roads proposed to be publicly maintained shall include dedication of adequate rights-of-way as identified in § 350-602D. Private thoroughfares and easements shall be allowed only in circumstances where a maintenance agreement and evidence of a properly created road easement is provided obligating individual landowners or homeowners' associations for maintenance of the private thoroughfares and/or easements. Easements and pavement widths and pavement sections for private thoroughfares and easements shall meet the requirements for public thoroughfares of similar function. In no case shall private thoroughfares be designed in such a way as to prevent access and/or passage of emergency vehicles.
(10)
Controlling access parallel to thoroughfares, i.e., reserve
strips, is prohibited.
(11)
All construction within the right-of-way or easement shall meet all applicable provisions of § 350-602E and F. A deviation from the referenced standards will be allowed only when testing of the materials and/or methods used shows the deviation to be equal or greater in quality to that of § 350-602F and requires approval from ESD.
(12)
All utilities within public rights-of-way or easements shall be coordinated with and comply with the requirements of the utility company or provider and Chapter 274, Use of Rights-of-Way, of the Doña Ana County Code, as amended.
(13)
Concrete collars for valves and manholes are required where
such valves and manholes fall within the County right-of-way.
(14)
Header curbs are required to be used when the thoroughfares
are not used to convey stormwater and the flows do not parallel the
road.
(15)
Public and private thoroughfares that exceed 1,500 feet in length
require secondary access designed to the specifications required by
this article. Private access roads/drives shall be platted easements
and shall be a part of the lot facing the easement.
(16)
Thoroughfare improvements shall be centered within the right-of-way
or the easement unless considered a half-thoroughfare as allowed within
this article.
(17)
The minimum right-of-way radius at intersections shall be 25
feet at the property line for all thoroughfare classifications in
use zones. Curb radii in a community type and transect zone shall
be regulated per Table 6.2, Community Type or Transect Zone Curb Radii
Dimensions. This table assigns lane widths and turning radii in community
types and transect zones; see Table 6.5, Development Intensity or
Transect Zone Thoroughfare Cross Sections.
Table 6.2 Community Type and Transect Zone Curb
Radii Dimensions
| |||||
---|---|---|---|---|---|
CURB RADIUS
| |||||
Design Speed
(mph)
|
Effective Turning Radius
(feet)
|
Rural
|
Low Intensity
|
Medium Intensity
|
High Intensity
|
15
|
10 to 15
|
NP
|
P
|
P
|
NP
|
20 to 25
|
15 to 20
|
P
|
P
|
P
|
P
|
30
|
20 to 30
|
P
|
NP
|
NP
|
NP
|
Note: P = permitted, NP = not permitted
|
(18)
Where use zone residential subdivisions are proposed along collector
or arterial thoroughfares that prohibit direct access to the thoroughfare,
the developer shall provide an approved physical barrier, including
but not limited to a solid wall or fence with landscaping along the
right-of-way, which shall be built at the time of thoroughfare construction.
The barrier shall conform to the clear sight triangle per Figure 6-1,
Use Zone Clear Sight Triangle Illustration, and shall be properly
maintained.
(19)
All signage shall be constructed with U channel posts/anchors
or other as approved by the ESD (NMDOT approved square posts/anchors
may be acceptable), in accordance with the Manual of Uniform Traffic
Control Devices, as amended.
(20)
The design and construction of bicycle and pedestrian facilities
is required for all thoroughfare cross sections.
(21)
In areas of erosive soil characteristics in excess of a grade of 3%, an additional four feet of paving and Types A and B curb and gutter, see § 350-608, Design drawings, or a six-inch asphalt dike shall be required. In areas where this section applies, water shall be let out at the nearest natural or man-made stream or pond but shall not exceed the hydraulic carrying capacity of the road per Table 6.18, Street Capacity Criteria.
C.
Clear sight triangles. The application of a clear sight zone is critical
on high-speed thoroughfares and on low-speed, walkable urban thoroughfares
with controlled intersections and right-of-way constraints per the
Institute of Transportation Engineers Context Sensitive Solutions.
The Doña Ana County Community Types and Transect Zones are
walkable urban areas and have specific clear sight criteria per Figure
6-2, Community Type and Transect Zone Clear Sight Triangle Illustration,
and Table 6.5, Walkable Urban Thoroughfare Cross Sections.
(1)
Section 350-602C shall apply to all other County roads, private roads, intersections, and public, private, and off-thoroughfare multiple parking area entrances, exits, and driveways to and from County and private roads and all property subject to Doña Ana County's jurisdiction. The standards established by these clear sight triangles regulations shall be met for all future construction or development which requires a building or other permit to be issued by the County, and shall apply to all existing or future landscaping or other nonstructural obstructions.
(2)
Design requirements for compliance. The County Engineering Services
Department may rely upon the American Association of State Highway
and Transportation Officials (AASHTO) publication, A Policy on Geometric
Design of Highways and Thoroughfares, current edition, in determining
the appropriate design requirements for a particular intersection
to comply with the requirements of these clear sight triangles regulations.
(a)
An area of unobstructed vision at street intersections, entrances/exits, permitting a vehicle to see approaching vehicles to the right or left. Nothing over three feet in height measured from the street at the lowest edge of pavement shall be permitted to obstruct a sight line, which shall be the front street and side street lines of a corner lot and a line connecting points from the intersection of the property line of such lot in accordance with § 350-608C. Additional distance may be necessary and is to be determined by a line of sight analysis. See Figure 6-1, Use Zone Clear Sight Triangle Illustrations.
(b)
Any existing trees located within the clear sight triangle will
be allowed to remain if all branches are trimmed from a height between
three feet and eight feet.
(c)
No single post or column within the designed triangle shall
exceed 12 inches in thickness at its greatest cross-section dimension.
(3)
Community type and transect zone clear sight distances shall
be determined by the character of the zone or community type, the
design speed of the thoroughfare, and the frequency of controlled
intersections. Measurements shall be from the back of curb rather
than the property line. See Figure 6-2, Community Type and Transect
Zone Clear Sight Triangle Illustration, and Table 6.5.
(4)
Permits. No building or grading permits shall be issued for the construction or alteration of any structure that would create a violation of § 350-602C. Construction or erection of utilities such as overhead poles, boxes, risers, etc., within the clear sight triangle which would interfere with the area of obstructed sight shall not be permitted except by special permit authorized by the ESD.
D.
Right-of-way and thoroughfare requirements. The location of collector
and arterial thoroughfares shall be generally guided by policy and
specifically located as development occurs. Coordination between the
County and the developer shall provide the appropriate classification
and alignment of all major and minor thoroughfares within and abutting
developments to encourage appropriate and efficient transportation
circulation patterns. Dedication and improvements for El Paso and
Mesilla Valley MPO corridors are required within and adjacent to proposed
developments.
(1)
An applicant shall be responsible for 100% of the thoroughfare
ROW and improvements within the boundaries of the development; or
(2)
For thoroughfares adjacent to the development, the applicant
shall provide the following thoroughfare ROW and improvements:
(3)
Access requirements for developments, including antiquated (previously
filed) subdivisions shall consist of the following:
(a)
Minimum access to a development shall be from a dedicated and
accepted public right-of-way or public easement. The developer shall
provide evidence that the linking road exists and has permission to
construct the thoroughfare. In instances where the access to a development
is unimproved, it shall be the responsibility of the applicant to
design and construct a minor local thoroughfare from the development
boundary to the nearest paved public thoroughfare. A wider width may
be required subject to the results of a traffic impact analysis (TIA).
If the thoroughfare linked to the proposed development is classified
as a major thoroughfare (e.g., a collector or arterial), the developer
shall provide the equivalent of a major local thoroughfare from the
boundary of the development to the nearest paved public thoroughfare.
(4)
Access to lots within a commercial, mixed-use, or industrial
development shall be from either a dedicated and accepted improved
public right-of-way or an improved access established by a permanent
private road and/or access easement a minimum of 60 feet wide; a wider
width may be required by this article or per the requirements of the
zoning district.
(5)
Access to lots within a residential development, proposed subdivision
or antiquated previously filed subdivision shall be from a dedicated
and improved paved public right-of-way.
(6)
All parcels shall provide a minimum of 50% of the necessary
additional right-of-way for adjacent thoroughfares to conform to the
required width as defined within this article for all roads classified
collector and above. One hundred percent of the required right-of-way
shall be required for local thoroughfares.
E.
Thoroughfare cross-section geometry. The Dona Ana County Comprehensive
Plan defines types of communities in the region relative to their
community character. Thoroughfares shall be built according to their
context classification per Table 6.4, Thoroughfare Classification
Context. The context is regulated by the adjacent land uses or zoning
districts per Table 6.3, Context per Community Type or Zone.
[Amended 12-8-2020 by Ord. No. 317-2020]
Table 6.3 Context per Community Type or Zone
| ||
---|---|---|
Community Types
|
Development Intensities
|
Context
|
|
Natural (N)
|
Rural
|
|
Rural (R)
|
Rural
|
|
Low Intensity (L)
|
Walkable urban
|
|
Medium Intensity (M)
|
Walkable urban
|
|
High Intensity (H)
|
Walkable urban
|
Transect Zones
|
Natural (T1)
|
Rural
|
|
Rural (T2)
|
Rural
|
|
Neighborhood Edge (T3)
|
Walkable urban
|
|
General Neighborhood (T4)
|
Walkable urban
|
|
Town Center (T5)
|
Walkable urban
|
Use Zones
|
Rural Density Residential (R5 and R5L)
|
Rural
|
|
Low Density Dwelling (D1 and D1L)
|
Suburban
|
|
Medium Density Dwelling (D2 and D2L)
|
Suburban
|
|
High Density Dwelling (D3)
|
Suburban
|
|
Mobile Home (DM)
|
Suburban
|
|
Mixed Use (MU)
|
Suburban or walkable urban
|
|
Neighborhood Commercial (C1)
|
Suburban
|
|
Community Commercial (C2)
|
Suburban
|
|
Regional Commercial (C3)
|
Suburban
|
|
Light Industrial (I1)
|
Suburban
|
|
Medium Industrial (I2)
|
Suburban
|
|
Heavy Industrial (I3)
|
Suburban
|
Table 6.4 Thoroughfare Classification Context
| ||
---|---|---|
Suburban
|
Walkable Urban
|
Rural
|
Principal arterial
|
Boulevard
|
Principal arterial
|
Minor arterial
|
Avenue, boulevard
|
Minor arterial
|
Collector
|
Street, avenue
|
Collector
|
Local
|
Low-intensity street, street
|
Local
|
(1)
Walkable urban thoroughfare cross sections per Table 6.5 are
required in all community-type subdivisions or thoroughfare improvements
in transect zones T3, T4 and T5. See Table 6.4, Thoroughfare Classification
Context.
(2)
Suburban thoroughfare cross sections per Table 6.6, Suburban
Thoroughfare Cross Sections, are required in all use zoned subdivisions
with lots less than 10,000 square feet, or any lot less than 80 feet
wide at the front building setback, or a gross density greater than
four dwelling units per acre.
(3)
Rural and natural zones thoroughfare cross sections per Table
6.7, Rural Use Zone Thoroughfare Cross Sections, are required per
Table 6.3, Context per Community Type or Zone.
(4)
The following documents shall be used to guide the planning,
design, and construction of motor vehicle, bicycle, and pedestrian
facilities:
(a)
Institute of Transportation Engineers (ITE) Context Sensitive
Solutions (CSS);
(b)
Association of American State Highway and Transportation Officials
(AASHTO) Policy on Geometric Design of Highways and Streets, as amended;
(c)
AASHTO Guide for the Development of Bicycle Facilities, as amended;
and
(d)
AASHTO Guide for the Planning, Design, and Operation of Pedestrian
Facilities, as amended.
(5)
The following requirements shall apply to all thoroughfares
intersecting public rights-of-way in Doña Ana County:
(a)
A list of constrained rights-of-way will or may be maintained
in the New Mexico DOT, Doña Ana County, local governments'
transportation plans and metropolitan planning organizations.
(b)
Roadway build-out is from the outside of the right-of-way towards
the centerline.
(c)
Internal street systems require access to adjacent subdivisions/phases.
(d)
All landscaping materials within the rights-of-way shall be
mutually agreed upon by the developer and Doña Ana County or
municipality having jurisdiction over the thoroughfares.
(e)
Multiuse paths shall be asphaltic surfaced a minimum of eight
feet wide.
(6)
Alternative thoroughfare cross sections. Alternatives to the
thoroughfare cross sections provided below may be approved by the
DRC, provided that they either are:
(a)
Proposed as part of a comprehensive, master planned development;
and:
[1]
Are based on generally accepted transportation planning and
traffic engineering design principles;
[2]
Provide equivalent accommodations for all transportation modes,
as appropriate;
[3]
Address emergency vehicle access requirements as determined
by the Fire Chief; and
[4]
Are recommended for approval by the County Engineer and the
Community Development Director or their designee; OR
(b)
Required for traffic calming, drainage, landscaping, transit,
biking or pedestrian enhancements; and:
[1]
Provide substantially equivalent street capacities based on
the street classifications;
[2]
Are based on generally accepted traffic engineering design principles;
[3]
Provide equivalent accommodations for all transportation modes,
as appropriate;
[4]
Address emergency vehicle access requirements as determined
by the County Fire Chief; and
[5]
Are recommended for approval by the County Engineer and the
Zoning Administrator or their designee; OR
(c)
Based on an alternative hierarchy of streets that includes,
at a minimum, street classifications per Table 6.4, Thoroughfare Classification
Context; and:
[1]
Are based on generally accepted traffic engineering design principles;
[2]
Provide equivalent accommodations for all transportation modes,
as appropriate;
[3]
Address emergency vehicle access requirements as determined
by the Fire Chief; and
[4]
Are recommended for approval by the County Engineer and the
Zoning Administrator or their designee.
(7)
Road and thoroughfares best management practices.
(a)
Description. Best practice will integrate road and thoroughfare
features within multimodal areas, supporting pedestrian and landscape
requirements.
(b)
Methods. Best practice will include active landscape features
combined with road and thoroughfare components to create complete
and connected amenities (e.g., walkable and accessible routes). Methods
will include chicanes, curb cuts, bio-swales, and other active landscape
features. Best practices should be coordinated with EDS and CDD staff.
[Amended 11-14-2017 by Ord. No. 294-2017]
(8)
Community type and transect zone thoroughfare cross sections.
(b)
Bicycle lanes shall be striped on both sides and include a buffer
strip and signs, directional arrows, and stencils.
(c)
Bicycle lanes shall not be built on roadways with design speeds
below 30 mph.
(d)
All on-street parking decisions shall be per Table 6.5.
(e)
All thoroughfares classified as avenue and above may be designated
as transit routes. Transit-related facilities, such as a shelter or
bus pull-out, may be required.
(f)
Three-hundred-foot block lengths are recommended.
(g)
Multiuse paths:
[1]
Shall not be placed immediately adjacent to avenues or boulevards,
especially in lieu of sidewalks or bicycle lanes.
[2]
May be used if they are incorporated with the overall design
and traverse the development on an independent right-of-way allowing
for more direct access to a destination.
[3]
Shall be asphaltic surfaced a minimum of eight feet wide.
(9)
Parkway assemblies. Parkway assemblies shall comply with the standards of § 350-403E, Parkway assemblies, and Tables 6.9, Typical Urban Parkways, 6.10, Typical Rural Parkways, and 6.11, Parkway Assemblies. Tables 6.9 and 6.10 illustrate the components of the parkway and Table 6.11 regulates the type and size for each component of the parkway.
(10)
Suburban thoroughfare cross sections.
(a)
If the right-of-way needed for complete roadway construction
is constrained, the cross section should be reduced in the following
order:
(b)
Bicycle lanes shall be striped on both sides and include buffer
strip and signs, directional arrows, and stencils.
(c)
Bicycle lanes shall not be built on roadways classified below
major local.
(d)
All on-street parking decisions shall be determined by the adjoining
land uses.
(e)
All roadways classified as collector and above may be designated
as transit routes. Transit-related facilities, such as a shelter or
bus pull-out, may be required.
(f)
Culs-de-sac require pedestrian and bike access through head,
except where a physical barrier exists. Exceptions approved by Zoning
Administrator.
(g)
Internal street system requires access to adjacent subdivisions/phases.
(h)
Three-hundred-foot block lengths and varied building setbacks
are recommended.
(i)
Multiuse paths:
[1]
Shall not abut travel lanes on arterials or collectors,
especially in lieu of sidewalks or bicycle lanes.
[2]
May be used if they are incorporated with the overall
design and traverse the development on an independent right-of-way
allowing for more direct access to a destination.
[3]
Shall be asphaltic surfaced a minimum of eight
feet wide.
Note: A 7-lane roadway cross section with 15 feet
raised median is shown above. However, 3- or 5-lane roadway may be
constructed based on approved traffic impact analysis. In such cases,
median width will be increased accordingly.
|
Note: A 5-lane roadway cross section with 15 feet
raised median is shown above. However, 3- or 5-lane roadway may be
constructed based on approved traffic impact analysis. In such cases,
median width will be increased accordingly.
|
Note: In primarily residential land use areas,
a 10-foot (minimum) multiuse path may be approved in lieu of the 2
5-foot bike lanes.
|
(11)
Rural thoroughfare cross sections.
(a)
Shoulders shall be paved with the travel lanes and striped on
both sides of the roadway.
(b)
The width of drainage swales, external to right-of-way, shall
be determined by the drainage report.
(c)
The construction materials for multiuse paths are determined
by the applicable design standards, minimum of asphaltic surfaced,
and shall:
[1]
Be brought to the intersection for safe crossing
at crosswalk.
[2]
Not be put in or terminate unless connecting to
established origin/destination, such as the trail system.
[3]
Be separated from the roadway by at least three
feet.
Table 6.8 Thoroughfare Geometry
| ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
|
|
|
|
Minimum Center-Line Radius (feet)
|
Vertical Curve Requirements4
|
| |||
Functional Classification
|
Design Speed (mph)1
|
AADT2
|
Minimum Right-of-Way (feet)
|
General Surfacing Requirements, Notes and Conditions3
|
Normal Crown4 (feet)
|
Super Elevation with 0.025 (feet)
|
For Crest Stopping Sight Distance8
|
For SAG Stopping Control Sight Distance8
|
Maximum Grade Change Allowed w/o Vertical Curve9
|
Maximum Grade Allowed10
|
Walkable Urban Thoroughfares
| ||||||||||
Boulevard
|
30
|
15,000 to 32,000
|
72
|
4 inches HMAC minimum
|
Varies according to cross section
|
Varies according to cross section
|
61
|
79
|
Required in all cases
|
7%
|
Avenue
|
30
|
< 22,000
|
73
|
4 inches HMAC minimum
|
Varies according to cross section
|
Varies according to cross section
|
61
|
79
|
0.50%
|
7%
|
Street
|
25
|
< 15,000
|
60
|
3 inches HMAC minimum
|
Varies according to cross section
|
Varies according to cross section
|
80
|
65
|
0.50%
|
8%
|
Low-intensity street
|
20
|
< 7,500
|
Varies according to cross section
|
2 inches HMAC minimum
|
Varies according to cross section
|
Varies according to cross section
|
32
|
35
|
1%
|
10%
|
Suburban Thoroughfares
| ||||||||||
Principal arterial
|
45
|
> 40,000
|
120
|
4 inches HMAC minimum
|
1,090
|
830
|
61
|
79
|
Required in all cases
|
7%
|
Minor arterial
|
45
|
< 40,000
|
100
|
4 inches HMAC minimum
|
1,090
|
830
|
61
|
79
|
0.50%
|
7%
|
Collector
|
35
|
< 20,000
|
85
|
3 inches HMAC minimum
|
430
|
340
|
80
|
65
|
0.50%
|
8%
|
Local
|
30 (major) 25 (minor)
|
< 7,500; see Table 6.6
|
Varies according to cross section
|
2 inches HMAC minimum
|
Varies according to cross section
|
Varies according to cross section
|
32
|
35
|
1%
|
10%
|
Rural Thoroughfares
| ||||||||||
Principal arterial
|
55
|
> 20,000
|
120
|
4 inches HMAC minimum
|
1,850
|
1,350
|
151
|
136
|
Required in all cases
|
7%
|
Minor arterial
|
55
|
< 20,000
|
100
|
4 inches HMAC minimum
|
1,850
|
1,350
|
84
|
96
|
0.50%
|
7%
|
Collector
|
35
|
< 5,000
|
85
|
3 inches HMAC minimum
|
430
|
340
|
29
|
49
|
0.50%
|
8%
|
Local
|
30
25 (cul-de-sac)
|
< 1,500
|
50
|
2 inches HMAC minimum
|
250
|
200
|
19
|
37
|
1%
|
10%
|
Thoroughfare Geometry General Notes for Table
6.8:
| |
A.
|
The location and preliminary alignment of principal
arterials and minor arterials shall be determined in cooperation with
the Mesilla Valley MPO Metropolitan Thoroughfare Plan and El Paso
MPO Metropolitan Transportation Plan based upon the TIA.
|
B.
|
Developer shall use the most recent version of all
AASHTO guides and policies.
|
C.
|
Replatting of an existing subdivision resulting in
the creation of additional lots shall be subject to the combination
and upgrade requirements of this article, succeeding subdivisions,
which require that existing streets within the subdivision be upgraded
to the minimum street pavement and rights-of-way required for the
new subdivision.
|
D.
|
Minimum slope in streets with standard curb and gutter
shall be 1/2% with a crown of minimum 1% and maximum 2%. Minimum slope
in streets with header curb shall be 0%. The crown on a 0% street
shall be a minimum 2%.
|
E.
|
All streets shall provide a roadside recovery clear
zone or other approved method of slope and barrier protection as described
in the latest edition of AASHTO Policy on the Geometric Design of
Highways and Streets.
|
F.
|
Follow New Mexico Department of Transportation Design
Standards to determine design speeds and center-line radii for state
roads.
|
Thoroughfare Geometry Supplemental Notes for
Table 6.8:
| |
1.
|
Posted speed limits shall be at or below the design
speed limits.
|
2.
|
The AADT listed above is a planning tool used to determine
the classification criteria.
|
3.
|
Surfacing width is measured from inside edge of curbing. The minimum allowable thickness is six inches of base course, two inches HMAC or six inches of concrete. Additional thicknesses may be required per § 350-602F.
|
4.
|
A minimum of 50 feet shall be maintained between vertical
points of intersection.
|
5.
|
Lengths of vertical curves longer than the minimums
resulting from the use of K values shown should be used wherever possible.
However, K should not exceed 143 when curb and gutter is used.
|
6.
|
The values for K shown are to be used in determining
the minimum length of vertical curve required by the use of the relationship
L = KA where: L = Length of vertical curve in feet; A = Algebraic
difference in grades expressed in percent; K = Design value indicative
of rate of curvature.
|
7.
|
Crest vertical curves are based on eye height of three
feet three inches, object height of six inches and AASHTO minimum
stopping distances. SAG vertical curves are based on AASHTO standards.
|
8.
|
Local residential streets with 90°, or near 90°,
turns may be designed with a minimum center-line radius of 80 feet
with the approval of the County Engineering Services Department.
|
9.
|
The cross slopes of culs-de-sac shall not exceed 2%.
|
10.
|
Road and utility easements for culs-de-sac may be
provided that serve five lots or less. When this option is utilized,
the roadway shall be designed to this article and the easement shall
be platted as part of the lots.
|
Note: Alternative parkway configurations may be
considered based on land use.
|
Table 6.10 Typical Rural Parkways
| |||
---|---|---|---|
Type A
|
Type B
| ||
(1)
|
Parkway
| ||
(b)
|
Planter and/or multiuse path
| ||
(c)
|
Swale
| ||
(2)
|
Transportation way
| ||
(d)
|
Shoulder
| ||
(e)
|
Travel lane
|
Note: Alternative parkway configurations may be
considered based on land use.
|
Table 6.11 Parkway Assemblies
[Amended 11-14-2017 by Ord. No. 294-2017; 12-8-2020 by Ord. No. 317-2020] | ||||||
---|---|---|---|---|---|---|
Details
|
Rural/T2
|
L/T3/D1/D1L
|
M/T4/D2/D2L
|
H/T5/D3/DM
|
Suburban Commercial/Industrial
| |
Curb type
|
Swale
|
Raised curb
|
Raised curb
|
Raised curb
|
Raised curb
| |
Walkway
| ||||||
Type
|
Not required
|
Path/sidewalk
|
Sidewalk
|
Sidewalk
|
Path/sidewalk
| |
Minimum Width (feet)
|
N/A
|
8 — path
5 — sidewalk
|
5
|
5
|
8 — path
5 — sidewalk
| |
Lighting
| ||||||
Maximum Range of Height (feet)
|
Not required
|
25 to 35
|
25 to 35
|
25 to 35
|
25 to 35
| |
Minimum Range of Spacing (feet)
|
N/A
|
At intersections, 250 to 400
|
At intersections, 250 to 400
|
At intersections, 250 to 400
|
At intersections, 250 to 400
| |
Planter
| ||||||
Type
|
Swale
|
Bio-swale
|
Continuous
|
Continuous or tree well
|
Continuous
| |
Minimum Width (feet)
|
N/A
|
5 — path
6 — sidewalk
|
5
|
72 square feet minimum — tree well; 5 minimum
|
6 — path
5 — sidewalk
|
F.
Standard specification for thoroughfare construction. All thoroughfares
constructed within Doña Ana County shall comply with New Mexico
Department of Transportation Standard Specification for Highway and
Bridge Construction, as adopted and amended.
(1)
All testing and construction inspections for all developments
shall adhere to the guidelines as set forth in the New Mexico Department
of Transportation Standard Specification for Highway and Bridge Construction,
as adopted and amended.
(2)
A pavement design report included with the final plat or final
document submittal shall include, but not be limited to:
(a)
Soil profiles shall be obtained from soil borings performed
within the proposed right-of-way and proposed borrow area, or in areas
determined to yield representative soils. Thoroughfare soil borings
shall be taken at an interval of 500 feet. Additional soil borings
may be required if soil characteristics change significantly. Soil
borings shall be advanced to a depth of at least five feet, or refusal,
whichever is shallower. In "cut" portions of the thoroughfare, the
depth of borings shall be measured from the proposed finished grade
elevation of the pavement. In "fill" portions of the thoroughfare,
the depth of borings shall be measured below existing grade. Soil
borings are required to classify materials to determine the thickness
of the layers of the road structure and to identify soils that are
excessively expansive or resilient. Such soils shall receive special
consideration by substitution with "engineered fill" or stabilization
with a suitable admixture and/or mechanical means. Field conditions
encountered with unsatisfactory materials shall be submitted with
pavement design calculations along with satisfactory design solutions.
(b)
All calculations used in the design, including traffic volumes,
soil types and structural numbers.
(c)
A table showing material properties used in the design and soil
parameters including R-values, modulus of resilience, and CBR. Soils
with R-values less than 45 require stabilization or removal to no
less than suitable underlying materials; chemical and/or mechanical
stabilization approved by ESD.
(d)
Laboratory test data indicating properties of materials tested.
(3)
A registered professional engineer, licensed to practice in
the State of New Mexico, shall perform pavement designs. The engineer
shall have demonstrated expertise in the design and analysis of rigid
and/or flexible thoroughfare pavements. All pavement design documents
shall be referenced in the design notes. All designs shall be based
on a minimum twenty-year life period.
(4)
The minimum thickness for a pavement structure shall be two
inches of HMAC overlaying six inches of base course, overlaying subgrade
preparation and soil stabilization. However, the actual thickness
will be determined from a pavement design analysis. Double-penetration
macadam surfacing may be allowed in areas for a temporary use and
as approved by ESD.
(5)
Double-penetration surface treatment is considered to have no
structural coefficient value.
(6)
Before starting to work on improvements in a development, the
developer shall arrange a conference with the ESD to review contract
specifications, review partial release procedures, and otherwise familiarize
the developer with the County's requirements and procedures for managing
development of communities. Individuals present at the conference
should be the developer, the County inspector, the County Engineer's
representative and the contractor. The developer shall provide five
sets of approved construction drawings to be retained by the County
at this meeting. Up to three additional approved copies for the developer
or his representative may be requested.
(7)
The developer or contractor shall obtain all necessary permits
prior to starting any grading or construction.
(8)
The developer or contractor shall give the ESD a minimum of
48 hours' notice prior to commencing any construction or testing of
material, including but not limited to the following:
(9)
The ESD shall order materials testing of materials and construction
in the development as soon as the contractor notifies ESD they are
available for testing. The ESD shall approve or reject the materials
and construction based on the results of those tests.
(10)
Testing of materials and construction fees shall be paid by
the permit holder if the installation fails testing.
(11)
The ESD shall have five working days to respond to the results
of materials tests.
(12)
Retesting of materials or construction due to failure to pass
compliance tests shall be paid by the construction permit holder.
Verification of payment for retesting shall be provided to the ESD
prior to final acceptance.
G.
One-year construction warranty. If, after final inspection and acceptance
of work performed and prior to the expiration of one year from the
date of acceptance or such longer period of time as may be prescribed
by the law or by the terms of any applicable special guarantee required
by the contract documents associated with the approval of the subdivision,
any work is found to be defective, whether the failure is due to construction
or materials failure, the applicant shall promptly and without cost
to the County, in accordance with an engineer's written instruction,
either correct such defective work or, if it has been rejected by
the County, remove it from the site and replace it with the terms
of such instructions. The County may have the defective work corrected
or the rejected work removed and replaced, and all direct and indirect
cost of such removal and replacement, including compensation for additional
professional services, shall be paid by the developer. All subdivisions
shall be insured by a one-year warranty of improvements that shall
obligate the applicant to repair to County standards any improvements
that fail within one year of the County's final inspection of construction
in the subdivision. In order to insure compliance with this article,
all subdivision improvements performed in the construction of roads
and drainage rights-of-way of a subdivision shall be subject to a
warranty binding the applicant to such terms as are mentioned above.
This warranty shall follow the sample forms in the Appendix.[1]
H.
Dedications. Where the developer wishes to dedicate facilities and/or
rights-of-way to the County, a written request by the owner shall
be submitted for review by the ESD and CDD. The dedication in the
final plat shall be submitted to the BOCC for acceptance or denial,
for the facilities and rights-of-way described in the subdivision's
disclosure statement and the terrain management plan.
I.
Traffic impact analysis (TIA). A TIA is used to assess the effects
of a particular development on the surrounding transportation network,
to determine what provisions are needed for safe and efficient site
access and traffic flow, and to establish mitigation requirements
where off-site impacts require improvements.
(1)
Off-site improvements shall not be required to be constructed
by the developer in order to address existing transportation system
deficiencies. However, any decrease in the LOS arising from the development
shall be corrected before a development/construction permit can be
issued. The degree of degradation shall be measured from the desired
LOS for the intersection on the major thoroughfare plan. A site threshold
assessment (STA) application shall be required for all development,
excluding a single-family residential dwelling on an existing lot.
Attached to the STA shall be a sketch showing traffic counts for pre-
and post-development and traffic count data from the Institute of
Transportation Engineers (ITE) Trip Generation Manual.
(2)
The level and extent of the required residential TIA shall conform
to the following warranting criteria, unless the ESD determines that
a higher level is required based on surrounding existing and proposed
development:
(a)
A Level One TIA shall address safety issues related to and the
impact of site-generated traffic upon the intersection created at
the primary point of access from the development to a County-maintained
road, to be evaluated at the point in time after projected full build-out
and occupancy of the development (generally for six to 25 residential
units);
(b)
A Level Two TIA shall incorporate the requirements of the Level
One TIA, and shall also be expanded to address off-site thoroughfare
and intersection improvements that may be required due to an increase
in vehicle miles traveled (VMT) or due to a compromise in safety that
is caused by traffic from the development. It is to be evaluated at
the time of projected full build-out and occupancy of the development,
and five years from the projected full build-out and occupancy (generally
for 26 to 100 residential units); or
(c)
A Level Three TIA shall incorporate the requirements of the
Level Two TIA, and shall also be evaluated at an additional horizon
year, which shall conform to the horizon year utilized by the regional
planning organization (RPO), Metropolitan Planning Organization (MPO),
or state highway plan for long-term transportation system modeling,
projection and planning (generally a twenty-year horizon and for 101
or greater residential units).
(3)
All nonresidential development shall require an STA. The level
and extent of the required TIA shall be determined by the ESD based
on the review of the STA and will conform to the following warranting
criteria:
(4)
TIAs shall address the following:
(a)
Introduction and summary, consisting of: the purpose and objectives
of the report; principal findings and conclusions; and recommendations
for improvements required to address impacts caused by traffic from
the development upon the existing transportation system.
(b)
Description of the proposed development, consisting of: description
of the site location and study area; brief description of the development;
and identification of any phasing or timing for implementation.
(c)
Description and extent of study, consisting of: identification
of study area, whether Level One, Two or Three; and if Level Two or
Three, identification of areas of influence and traffic impact.
(d)
Description of study time frames, consisting of: Level One TIA:
first year after projected full build-out and occupancy; Level Two
TIA: first year after projected full build-out and occupancy, and
five years after full build-out; and Level Three TIA: first year after
projected full build-out and occupancy, five years after full build-out,
and horizon year (generally 20 years).
(e)
Existing land use and development within the study area, including:
existing land uses in the vicinity of the development; concurrent
development, including any subdivisions or development approved or
under construction; and future development currently in the planning
stage.
(f)
Description of existing conditions of the transportation system,
including identification of existing access and thoroughfare characteristics,
including the presence of any existing or future collector or arterial
roads as identified on the regional planning organization (RPO) or
Metropolitan Planning Organization (MPO) plan or state highway plan
in the vicinity of the proposed development; traffic control and transportation
system conditions; safety issues and concerns, including, but not
limited to, sight distance and accident rates; and (background) traffic
volumes, including turning volumes, capacity and level of service.
(g)
Projected traffic and traffic impacts, consisting of: computation
of vehicle trips generated by the development, in accordance with
the requirements of the Trip Generation Manual, Institute of Transportation
Engineers, as amended; identification and discussion of estimated
a.m. and p.m. peak-hour traffic, including turning volumes, daily
and seasonal variations, if appropriate, and pass-by trips; trip distribution
and assignment; and effects of site-generated traffic upon capacity,
level of service, and safety of the thoroughfare system.
(h)
Improvement analysis, including: evaluation of number of lanes,
lane and shoulder widths, lateral clearances, design speeds, deceleration/acceleration
lanes, horizontal and vertical alignments, sight distance, pavement
conditions, existing access and use, traffic control, and pedestrian
uses; and identification of and cost estimates for transportation
system improvements required to accommodate existing traffic, as well
as existing and projected site traffic.
(i)
Findings and recommendations, including: appropriateness and
adequacy of site access; existing and projected traffic impacts; and
required improvements, including those required as a condition of
approval of the subdivision or development.
(j)
The following documents are incorporated by reference, and shall
be used in the preparation of TIAs, including their data, requirements,
and procedures: Trip Generation Manual, Institute of Transportation
Engineers, as amended; A Policy on the Geometric Design of Highways
and Thoroughfares, American Association of State Highway and Transportation
Officials as amended; Manual on Uniform Traffic Control Devices for
Thoroughfares and Highways, as amended; Highway Capacity Manual 2000,
Transportation Research Board, and the Highway Capacity Software,
McTrans HCS2000, latest upgrade or the approved equal; and Access
Management Manual, New Mexico Department of Transportation, or other
as amended applicable design standard.
(k)
Designers shall strive to provide the lowest vehicle miles traveled
(VMT) feasible with anticipated conditions.
(l)
Prior to final plat approval, improvement requirements determined
to be necessary to maintain, restore or improve existing thoroughfare
LOS on highways, major arterials, arterials, collectors and major
locals may be subject to a cooperative agreement between the County
and the developer. The agreement shall be in place prior to the filing
of the final plat.
(m)
Travel demand management strategies: Include an outline of travel
demand management strategies to mitigate traffic impacts created by
proposed development and implementable measures for promoting alternate
modes of travel, including but not limited to the following: incorporate
design features that facilitate walking, biking, and the use of transit
services to access a proposed development, including features such
as transit shelters and benches site amenities, site design layouts,
orientations and connections to other components of the multimodal
transportation system to increase convenience for alternate modes
and reduce multiple trips to and from the site; provide connections
to existing offsite pedestrian, bicycle, and transit systems that
are as direct as possible given the existing limitations of obstructions,
terrain and land ownership.
(n)
Trip generation reductions: Credit for any trip reductions is
subject to review and approval in advance by the ESD. Any anticipated
trip reduction assumptions shall be discussed and approved by the
ESD prior to the preparation of the TIA. Trip reductions typically
fall into one of two categories: those that reassign some portion
of the trip generation from the thoroughfare network adjacent to the
project site (pass by and diverted trip reductions), and those that
remove trips generated from the land use trip generation (internal
and modal split reductions).
A.
Operation. Access and driveways shall operate as at-grade intersections.
They shall be designed to provide for adequate sight distance and
acceptable levels of traffic operations, and provide control and geometry
that is consistent with the intensity of use of the driveway, the
intended function of the thoroughfare and to comply with this article.
B.
State permit. A permit shall be obtained from the New Mexico Department
of Transportation (NMDOT) district office for all driveways accessing
state-maintained roads prior to the approval of any development and
construction documents.
C.
Access permit. An access permit obtained from the ESD is required for all driveways accessing existing and proposed County roads prior to the approval of any construction documents or issuance of a building permit. See § 350-601E.
E.
Private driveway access to single-family lots. Private driveway access
to single-family lots shall be from local thoroughfares. See Table
6.4, Thoroughfare Classification Context. However, if this is the
only legal access to an existing parcel of land, one driveway permit
will be permitted.
(1)
A common driveway is a mutual entrance to two lots. The minimum
width allowed is 20 feet. A letter of concurrence, signed by both
property owners, shall be provided prior to issuance of the permit.
(2)
For lots with a forty-foot frontage or less, the driveway shall
be located where it is common for two lots, and provides an on-thoroughfare
parking area, where possible.
(3)
The minimum distance between two driveways on one lot is 22
feet.
(4)
The minimum distance between two driveways on adjacent lots
is 30 feet.
(5)
The minimum length of frontage for two driveways is 120 feet.
(6)
For corner properties, the location of the drivepad on local
thoroughfares shall be a minimum of 20 feet from the curb return.
(7)
The driveway shall be designed so that the drainage patterns
will not allow stormwater to either enter or leave the public ROW,
unless otherwise provided for in the original development.
F.
Nonresidential, mixed-use, and multiple-family residential driveways. For nonresidential driveways and multiple-family housing developments, the number of driveways and type of construction are dependent upon the classification of the thoroughfare and the traffic to be generated by the proposed development. Driveway widths shall be governed by the site standards per Tables 3.7 through 3.11 and 5.3 through 5.16 and for lots and driveways, §§ 350-304D and 350-502C.
(1)
Thoroughfare classification. The County's thoroughfare classification
is determined by the analysis of its current functional classification
and projected land uses and as defined by this article. The major
thoroughfare plan, as recommended by local MPOs, shall be used as
a basis for the classification of thoroughfares within Doña
Ana County. Thoroughfare classification is based upon the community
type according to Table 6.4, Thoroughfare Classification Context.
(2)
Traffic generation factors. Points of access shall be designed to a high standard to minimize operational and safety problems. Driveway characteristics may include reduced entrance grades, and deceleration lanes. (See Tables 3.7 through 3.11 and 5.3 through 5.16 and Lots and Driveways, §§ 350-304D and 350-502C).
(3)
Spacing of driveways from intersections and driveways. The distances
in Table 6.12, Spacing of Driveways from Intersections, shall be used
as minimums for existing parcels less than two acres in size when
determining the spacing of driveways from intersections and other
driveways.
Table 6.12 Spacing of Driveways from Intersections
| ||||||
---|---|---|---|---|---|---|
|
Arterial
|
Collector
|
Local
| |||
Type of Thoroughfare
|
Approach Distance
(feet)
|
Departure Distance
(feet)
|
Approach Distance
(feet)
|
Departure Distance
(feet)
|
Approach Distance
(feet)
|
Departure Distance
(feet)
|
Principal arterial
|
300
|
200
|
200
|
150
|
150
|
100
|
Minor arterial
|
200
|
150
|
150
|
100
|
100
|
100
|
Collector
|
150
|
150
|
100
|
100
|
75
|
75
|
Local
|
150
|
150
|
100
|
100
|
75
|
75
|
Notes:
| |
(1)
|
Additional distance may be required based upon queuing requirements.
|
(2)
|
Multiuse driveways will be classified the same as local thoroughfares
for the purpose of this table.
|
(4)
Driveways with median access.
(a)
Thoroughfares with median channelization shall have driveways
located with the center line of the driveway approximately centered
on the median openings. Where a driveway exists on the opposite side
of the thoroughfare, the center line of the new driveway that utilizes
the median opening shall be located within 10 feet of the existing
driveway center line. Driveways not meeting these criteria shall be
located a minimum of 75 feet from the existing median opening.
(b)
Driveways on thoroughfares without median channelization shall
be constructed on opposite sides of the thoroughfare. If driveways
are not to be opposite each other, they are offset a minimum of 50
feet for local thoroughfares and a minimum of 75 feet for collector
and arterial thoroughfares. The center lines shall be within 15 feet
of each other.
(5)
Curb return construction. Curb returns may be allowed on arterials
if vehicles are entering and exiting large-scale commercial/industrial
developments. They may be permitted in other cases given sufficient
traffic generation or substantial use by vehicles with a large turning
radius. Vehicle swept path and turning movement analyses are required
submittals.
(6)
Drivepads for minor and principal arterials, collectors, major
local and walkable urban thoroughfares:
(a)
Two-way drivepads require a twenty-four-foot minimum width.
(b)
One-way drivepad shall be 20 feet in width. These are only permitted
where the circulation is self-enforcing; that is, when angle parking
and one-way aisles are used in establishing the one-way pattern from
entrance to exit.
(c)
Drivepad widths for larger vehicles may be up to 36 feet for
tractor-trailer combinations and mobile homes.
(7)
Drivepads for local thoroughfares.
(a)
Twenty-foot minimum for two-way access; however, 24 feet may
be permitted for commercial or mixed-use properties.
(b)
No backing from designated parking stalls into the thoroughfares
is permitted.
(c)
One-way drivepad shall be 18 feet in width. These are only permitted
where the circulation is self-enforcing; that is, when angle parking
and one-way aisles are used in establishing the one-way pattern from
entrance to exit.
(8)
Curb return entrances. The width and radius of the entrance
are dependent upon the design vehicle in all use zoning districts
and must be modeled via vehicle swept path and turning movement analyses.
See Table 6.13, Arterial and Collector Access.
(a)
All curb return entrances require ADA ramps and valley gutters.
(b)
Additional right-of-way or public thoroughfare easement may
be required to be dedicated or granted.
Table 6.13 Arterial and Collector Access
| ||||||
---|---|---|---|---|---|---|
|
Single Entrance/Exit Widths
(feet)
|
Divided Entrance/Exit Widths
(feet)
| ||||
Entrance
|
Exit
| |||||
Design Vehicle
|
Radius at Back of Curb
(feet)
|
No Median Access
|
With Median Access
|
|
No Median Access
|
With Median Access
|
Car only
|
20 to 30
|
20
|
20 to 30
|
12
|
12
|
20
|
SU-301
|
24 to 30
|
30
|
36 to 40
|
20
|
18
|
22
|
WB-402
|
30 to 40
|
30 to 40
|
40 to 45
|
22
|
20
|
24
|
WB-503
|
35 to 40
|
40 to 45
|
45
|
25
|
20
|
24
|
Notes:
| |
1 Single-unit truck, 30 feet long,
wheel base 20 feet (refuse truck).
| |
2 Tractor-trailer, 50 feet long,
wheel base 40 feet.
| |
3 Tractor-trailer, 55 feet long,
wheel base 50 feet (18-wheeler).
|
(9)
Striping and signing.
(a)
Entrances and exits of any driveway shall be marked with arrows
to define direction, such as one-way exit and entrance signs and turn
restriction signs. For further details on appropriate signing and
striping used for entrances, see the Manual for Uniform Traffic Control
Devices (MUTCD), as amended.
(b)
The developer shall provide a NMPE certified traffic control
plan for review and approval by the ESD in accordance with the MUTCD.
The developer shall implement the approved plan at the developer's/applicant's
expense for work within the County right-of-way.
(10)
Grades. The maximum initial grades for curb return entrances with left-turn access shall be a positive 4% (+4%) for right-turn-in-only entrances and a positive 6% (+6%) for right-turn-out-only entrances. Drivepads shall be constructed to the thoroughfare right-of-way line per § 350-608B, Drivepad and intersection drawings, except that a minimum drivepad depth of 6 1/2 feet shall be used.
(11)
Visibility for driveways. Visibility shall be maintained in accordance with the AASHTO Guidelines for Intersection Visibility. Landscaping, fencing and/or berming shall meet the requirements for driveway visibility. See § 350-602C.
(12)
Right-turn deceleration lanes for tapers. A modified right-turn
deceleration lane or a taper is required on arterial thoroughfares
where the right-turning volumes will not exceed the following numbers
in Table 6.14, Right-Turn Deceleration Lanes or Tapers, for either
the a.m. or p.m. peak of the adjacent thoroughfare traffic.
Table 6.14 Right-Turn Deceleration Lanes or Tapers
| ||
---|---|---|
Requirement
|
Design Speed of Thoroughfare
(mph)
|
Length
(feet)
|
Taper Required
| ||
1 to 15 trips/day
|
45 to 50
|
200
|
|
35 to 45
|
150
|
|
Under 35
|
Not required
|
Deceleration Lane Required
| ||
15 or more trips/day
|
45 to 50
|
200
|
15:1 taper
|
35 to 45
|
150
|
|
Under 35
|
Not required
|
Note: Additional right-of-way for deceleration
lanes or tapers shall be dedicated, if necessary.
|
(13)
Left-turn lanes. Left-turn lanes shall be required if a driveway
utilizing a median opening is constructed. The left-turn lane provides
for both the stacking and deceleration of left-turning vehicles. Left-turn
lane lengths are dependent upon a number of factors, including the
cycle length of the upstream signal, left-turn arrival rate, and queuing
factor. For unsignalized left turns, the formula in Table 6.15, Turnbay
Length for Unsignalized Left Turns, shall be used to determine turn
bay length.
Table 6.15 Turnbay Length for Unsignalized Left Turns
| ||
---|---|---|
Mean Arrival Rate
(vehicles/minute)
|
Turnbay Length
(feet)
|
Width
(feet)
|
0.25
|
100 taper
|
10
|
0.25 to 1.0
|
50 + transition
|
10
|
1.5
|
75 + transition
|
10
|
2.0
|
100 + transition
|
10
|
For mean arrival rates above 2 vehicles/minute, the following
formula should be used:
|
Length = VI/C *v*L
|
Where:
| |||
VI
|
=
|
number of left turns in the peak hour
| |
C
|
=
|
cycle length of upstream signal
| |
VI/C
|
=
|
mean arrival rate
| |
V
|
=
|
Poisson arrival factor for 95% confidence level
| |
L
|
=
|
average vehicle length — use 20 feet per vehicle for queues
with 1% trucks
|
Transitions
| |
Design Speed (mph)
|
Taper Length
|
30 to 55
|
15:1 x lane width
|
(14)
Channelized right and left turns. Right- and left-turn channelization
shall be required based upon factors such as one-way thoroughfares,
the necessary restriction of movements at a driveway or to meet applicable
standards as set forth in NMDOT's State Access Management Manual.
(15)
Signalization. When a development causes a significant increase
in traffic to warrant a signal (per MUTCD), the developer will be
financially responsible for the signal installation as set forth in
the NMDOT State Access Management Manual. A financial guarantee for
a future signal shall be submitted for approval by the BOCC.
(16)
Abandoned driveways. Any drivepad/driveway that has a change
in use shall be replaced by the property owner with driveways meeting
these minimum standards.
(17)
Common driveways. Driveways that straddle property lines or
share access shall be recorded by a grant of easement document prior
to the issuance of an access permit. This easement shall also recognize
any existing lot lines, utilities, or other easements.
(18)
Driveway construction. Driveways and parking areas shall be
constructed and surfaced per the approved design and specified in
the permit application. No surfacing shall be placed upon a driveway
until an inspection is made and the grading work is approved by the
ESD.
(19)
Lighting. Exterior lighting is required for all employee and
visitor parking areas, walkways, building entrances and exits, and
ingress and egress. No light standard shall exceed 10 feet in height.
No light source shall be fixed to any building so that rays are perpendicular
to the building face. All direct rays of the light source shall be
confined to the site.
(20)
Driveway apron maintenance. The County does not assume any responsibility
for the removal or clearance of snow, sleet, ice, silt, vegetation,
wind-blown debris or the opening of windrows of such materials upon
any portion of any driveway or entrance along any County road.
(21)
Drainage. Drainage design shall conform to NMDOT requirements
and to all applicable local regulations and requirements. Drainage
on side ditches shall not be altered or impeded. The applicant/owner
shall provide suitable and approved drainage structures as required
by the County based on acceptable engineering practices. The following
engineering practices and information shall be submitted by permit
applicants when any changes are made in drainage conditions:
(a)
A report including a description of the existing drainage conditions,
the proposed revisions and the effect of the proposed changes on existing
conditions. It shall include, but not be limited to, proposed drainage
structures that shall carry the design flow of water in the side ditches.
(b)
Maps and drawings shall address all pertinent features of the
proposed modification. This may include, but not be limited to, site
maps, drainage area maps, contour maps, grading plans, structure profiles,
and channel profiles.
(c)
Hydrologic and hydraulic calculations are required for design
discharge, headwater elevations, tailwater elevations, flow depths
and flow velocities in channels, design discharge, and headwater elevations
in culverts.
(22)
Pipe culverts placed parallel to thoroughfares shall have a
concrete blanket placed on both ends of the structure. The concrete
blanket shall have horizontal two-inch steel pipes (extra-strong AISC
designation) placed such that the spacing shall not exceed 24 inches
and shall be designed so that the grate can be lifted up or removed
for cleaning purposes.
G.
Parking requirements. Parking requirements for multifamily and all
nonresidential uses shall follow the Institute of Transportation Engineers
(ITE) Parking Generation Manual, most current edition.
[Amended 11-14-2017 by Ord. No. 294-2017]
(1)
Parking areas for uses where 10 spaces are required shall be
paved with at least two inches thickness of Hot-Mix pavement over
six inches of Base Course. If less than 10 spaces are required, then
ADA spaces shall be paved, with other parking spaces surfaced with
a minimum of six inches of Base Course; thickness as structurally
necessary.
A.
Basis for establishing area of special flood hazard. The areas of
special flood hazard identified by the effective Federal Emergency
Management Agency in a scientific and engineering report entitled
"The Flood Insurance Study for Doña Ana County, New Mexico,"
with accompanying Flood Insurance Rate Maps and Flood Boundary-Floodway
Maps (FIRM and FBFM), and any revisions thereto are hereby adopted
by reference and declared to be a part of this section.
B.
Duties and responsibilities of Floodplain Administrator. Duties and
responsibilities of the Floodplain Administrator shall include, but
not be limited to, the following:
(1)
Maintain and hold open for public inspection all records pertaining
to the provisions of this chapter.
(2)
Review permit application to determine whether proposed building
sites, including the placement of manufactured homes, will be reasonably
safe from flooding.
(3)
Review all applications for floodplain development permits required
by adoption of this chapter.
(4)
Review permits for proposed development to assure that all necessary
permits have been obtained from those federal, state or local governmental
agencies (including Section 404 of the Federal Water Pollution Control
Act Amendments of 1972, 33 U.S.C. § 1334) from which prior
approval is required.
(5)
Where interpretation is needed as to the exact location of the
boundaries of the areas of special flood hazards (for example, where
there appears to be a conflict between a mapped boundary and actual
field conditions), the Floodplain Administrator shall make the necessary
interpretation.
(6)
Notify, in riverine situations, adjacent communities and the
state coordinating agency, which is the New Mexico State Engineer,
prior to any alteration or relocation of a watercourse, and submit
evidence of such notification to the Federal Emergency Management
Agency.
(7)
Assure that the flood-carrying capacity within the altered or
relocated portion of any watercourse is maintained.
(8)
When base flood elevation data have not been provided in accordance with § 350-604I, the Floodplain Administrator shall obtain, review and reasonably utilize any base flood elevation data and floodway data available from a federal, state or other source, in order to administer the provisions of § 350-604F through I.
(9)
When a regulatory floodway has not been designated, the Floodplain
Administrator shall require that new construction, substantial improvements,
or other development (including fill) shall not be permitted, unless
it is demonstrated that the cumulative effect of the proposed development,
when combined with all other existing and anticipated development,
will not increase the water surface elevation of the base flood more
than one foot at any point within the community.
(10)
Under the provisions of 44 CFR Chapter I, Subchapter B, Part
65, § 65.12, of the National Flood Insurance Program regulations,
a community may approve certain development in Zones A, AE, AH and
AO on the community's FIRM which increases the water surface elevation
of the base flood by more than one foot, provided that the community
first applies for a conditional FIRM revision through FEMA.
C.
Floodplain development permit. A floodplain development permit shall
be required for all development in a FEMA special flood hazard area
( SFHA), (refer to Appendix BB).
[Amended 12-8-2020 by Ord. No. 317-2020]
D.
Elevation certificates, construction. An elevation certificate (EC)
is required for all construction within a Federal Emergency Management
Agency (FEMA) designated floodplain. Construction may not be started
until the applicant has provided an elevation certificate that has
been accepted by a certified floodplain manager (CFM) in the Flood
Commission. Procedures for every situation described below can be
found in Appendix BB.
[Added 12-8-2020 by Ord.
No. 317-2020[1]]
(1)
Building permits. New development in a FEMA SFHA will require
three elevation certificates to be reviewed and accepted by the Flood
Commission. An EC is required prior to receiving a permit, prior to
pouring a foundation, and prior to receiving a certificate of occupancy.
(a)
Pre-construction elevation certificate. An elevation certificate
must be signed and sealed by a New Mexico registered professional
surveyor and returned to the Flood Commission prior to any construction
on site has begun. A building permit can be released by the Flood
Commission upon receipt and acceptance of this EC.
[1]
Required components:
[a]
Benchmark.
[b]
Datum.
[c]
Highest and lowest adjacent grade elevations. The
proposed building pad footprint should be staked out by the surveyor/developer
prior to any development or alteration of existing topography, with
all corners marked. Elevations for all corners shall be surveyed,
with the highest and lowest of the observed elevations serving as
the highest and lowest adjacent grade, respectively.
[d]
Photographs of site in existing conditions.
(b)
Under-construction elevation certificate. An elevation certificate
must be signed and sealed by a New Mexico registered professional
surveyor, and accepted by the Flood Commission prior before the structure
foundation is poured. Once the forms are set for the foundation, elevations
should be obtained for anticipated top of bottom floor, and any changes
of adjacent grade shown on the pre-construction elevation certificate
should be noted.
[1]
Required components:
[a]
Benchmark.
[b]
Datum.
[c]
Highest and lowest adjacent grade elevations. The
highest and lowest adjacent grades should be observed at the top of
building pad.
[d]
Anticipated top of bottom floor elevation. Elevation
shall be shot at the top of wood or metal forms.
[e]
Photographs of installed forms, from all sides.
(c)
Post-construction elevation certificate. An elevation certificate
must be signed and sealed by a New Mexico registered professional
surveyor, and accepted by the Flood Commission Office after construction
is complete. A certificate of occupancy will not be issued until a
post construction EC is accepted by the Flood Commission. Elevations
shall be obtained for top of bottom floor for main structure or any
attached garage or accessory structure, machinery/equipment servicing
the structure, and all adjacent grades.
(2)
Building permits, existing development will require one elevation
certificate to be reviewed and accepted by the Flood Commission. An
EC shall only to be required for an existing structure when obtaining
a new flood insurance policy in order to reflect property changes
that may affect insurance premiums, transfer of ownership or to accompany
a change in financing options.
(a)
Post-construction elevation certificate. An elevation certificate
must be signed and sealed by a New Mexico registered professional
surveyor, and accepted by the Flood Commission Office after construction
is complete. A certificate of occupancy will not be issued until a
post construction EC is accepted by the Flood Commission. Elevations
shall be obtained for top of bottom floor for main structure or any
attached garage or accessory structure, machinery or equipment servicing
the structure, and all adjacent grades.
(3)
Mobile home installation permits. New construction will require
two elevation certificates to be reviewed and accepted by the Flood
Commission. An EC is required prior to receiving an installation permit.
(a)
Pre-placement elevation certificate. An elevation certificate
must be signed and sealed by a New Mexico registered professional
surveyor and returned to the Flood Commission prior to any construction
on site has begun. A mobile home installation permit may be released
by the Flood Commission upon receipt and acceptance of elevation certificate.
(b)
Post-placement elevation certificate. An elevation certificate
must be signed and sealed by a New Mexico registered professional
surveyor, and returned to the Flood Commission Office after placement
is complete.
(4)
Elevation certificates, limits on liability. The acceptance
of an elevation certificate and related information shall not constitute
a representation, guarantee or warranty of any kind or nature by Doña
Ana County or any other political subdivision, or by an officer or
employee of any of them, of the practicability or safety of any structure
or activity, and such acceptance shall create no liability upon or
cause of action against any public body, officer, or employee for
damage that may result therefrom.
(5)
Certificate of occupancy. Certificates of occupancy shall not
be issued until all applicable requirements of the currently adopted
Building Code and this chapter are met. Once a certificate of occupancy
is issued, a business registration shall be obtained for nonresidential
uses when required by law.
E.
Interpretation. In the interpretation and application of this chapter,
all provisions shall be:
[Amended 12-8-2020 by Ord. No. 317-2020]
F.
Warning and disclaimer of liability. The degree of flood protection
required by this chapter is considered reasonable for regulatory purposes
and is based on scientific and engineering considerations. On rare
occasions, greater floods can and will occur and flood heights may
be increased by man-made or natural causes. This chapter does not
imply that land outside the special flood hazard areas or uses permitted
within such areas will be free from flooding or flood damages. This
chapter shall not create liability on the part of the community or
any official or employee thereof for any flood damages that result
from reliance on this chapter or any administrative decision lawfully
made thereunder.
[Amended 12-8-2020 by Ord. No. 317-2020]
G.
General standards. In all areas of special flood hazards, the following
provisions are required for all new construction and substantial improvements:
[Amended 12-8-2020 by Ord. No. 317-2020]
(1)
All new construction or substantial improvements shall be designed
(or modified) and adequately anchored to prevent flotation, collapse
or lateral movement of the structure resulting from hydrodynamic and
hydrostatic loads, including the effects of buoyancy;
(2)
All new construction or substantial improvements shall be constructed
by methods and practices that minimize flood damage;
(3)
All new construction or substantial improvements shall be constructed
with materials resistant to flood damage;
(4)
All new construction or substantial improvements shall be constructed
with electrical, heating, ventilation, plumbing, and air conditioning
equipment and other service facilities that are designed or located
so as to prevent water from entering or accumulating within the components
during conditions of flooding;
(5)
All new and replacement water supply systems shall be designed
to minimize or eliminate infiltration of floodwaters into the system;
(6)
New and replacement sanitary sewage systems shall be designed
to minimize or eliminate infiltration of floodwaters into the system
and discharge from the system into floodwaters; and
(7)
On-site waste disposal systems shall be located to avoid impairment
to them or contamination from them during flooding.
H.
Specific standards. In all areas of special flood hazards where Base
Flood Elevation (BFE) data have been provided on the Flood Insurance
Rate Map (FIRM) or Flood Insurance Study (FIS) as set forth in:
[Amended 12-8-2020 by Ord. No. 317-2020]
(1)
Residential construction. New construction substantial improvement,
or reconstruction due to substantial damage of any insurable structure,
in addition to all equipment or mechanical items servicing the structure
shall have the lowest floor (including basement) elevated to one foot
above the base flood elevation. A registered professional land surveyor
shall submit an elevation certification to the Floodplain Administrator
to verify that the standard of this section is satisfied.
(2)
Nonresidential construction. New construction, substantial improvements
or reconstruction due to substantial damage of any insurable commercial,
industrial or other nonresidential structure, in addition to all equipment
or mechanical items servicing the structure, shall be designed so
that below the BFE, the structure is watertight. This requires either
that the lowest floor (including basement) is elevated to one foot
above the BFE or, together with attendant utility and sanitary facilities,
walls are substantially impermeable to the passage of water, and with
structural components having the capability of resisting hydrostatic
and hydrodynamic loads and effects of buoyancy. A registered professional
engineer or architect shall develop and/or review structural design,
specifications, and plans for the construction. A registered professional
engineer or land surveyor shall certify that the design and methods
of construction are in accordance with accepted standards of practice
as outlined in this section. A record of such certification, which
includes the specific elevation (in relation to mean sea level) to
which such structures are floodproofed, shall be maintained by the
Floodplain Administrator.
(3)
Enclosures. New construction and substantial improvements shall
be designed to automatically equalize hydrostatic flood forces on
exterior walls by allowing for the entry and exit of floodwaters.
This includes fully enclosed areas below the lowest floor that are
usable solely for parking of vehicles, building access or storage
in an area other than a basement, which are subject to flooding. Designs
for meeting this requirement shall either be certified by a registered
professional engineer or architect or meet or exceed the following
minimum criteria:
(a)
A minimum of two openings having a total net area of not less
than one square inch for every square foot of enclosed area subject
to flooding shall be provided.
(b)
The bottom of all openings shall be no higher than one foot
above grade.
(c)
Openings may be equipped with screens, louvers, valves, or other
covering or devices, provided that they permit the automatic entry
and exit of floodwaters.
(4)
Manufactured homes.
(a)
All manufactured homes to be placed within Zones A, AE, AH and
AO on a community's FIRM shall be installed using methods and practices
which minimize flood damage. For the purposes of this requirement,
manufactured homes shall be elevated and anchored to resist flotation,
collapse, or lateral movement. Methods of anchoring may include, but
are not limited to, use of over-the-top or frame ties to ground anchors.
This requirement is in addition to applicable state and local anchoring
requirements for resisting wind forces.
(b)
Manufactured homes that are placed or substantially improved
within Zones A, AE, AH and AO on the community's FIRM on sites outside
of a manufactured home park or subdivision, in a new manufactured
home park or subdivision, in an expansion to an existing manufactured
home park or subdivision, or in an existing manufactured home park
or subdivision on which a manufactured home has incurred substantial
damage as a result of a flood are required to be elevated on a permanent
foundation such that the lowest floor of the manufactured home is
elevated to or above the base flood elevation and shall be securely
anchored to an adequately anchored foundation system to resist flotation,
collapse, and lateral movement.
(c)
Manufactured homes to be placed or substantially improved on
sites in an existing manufactured home park or subdivision with Zones
A, AE, AH and AO on the community's FIRM that are not subject to the
provisions of this section shall be elevated so that:
[1]
The lowest floor of the manufactured home is at or above the
base flood elevation; or the manufactured home chassis is supported
by reinforced piers or other foundation elements of at least equivalent
strength that are no less than 36 inches in height above grade and
is securely anchored to an adequately anchored foundation system to
resist flotation, collapse and lateral movement.
(5)
Recreational vehicles. Recreational vehicles placed on sites
within Zones A, AE, AH and AO on the community's FIRM shall either:
(a)
Be on the site for a maximum of 180 consecutive days;
(b)
Be fully licensed and ready for highway use; or
(c)
Meet the permit requirements of § 350-601G(1) and the elevation and anchoring requirements for manufactured homes in § 350-604H of this section. A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick-disconnect-type utilities and security devices, and has no permanently attached additions.
I.
Standards for subdivision proposals.
[Amended 12-8-2020 by Ord. No. 317-2020]
(1)
Base flood elevation data shall be generated for subdivision proposals and other proposed development, including the placement of manufactured home parks and subdivisions, which is greater than 50 lots or five acres, whichever is lesser, if not otherwise provided pursuant to § 350-604A or 350-604B(8).
(2)
All subdivision proposals, including the placement of manufactured
home parks and subdivisions, shall have adequate drainage provided
to reduce exposure to flood hazards.
(3)
All subdivision proposals, including the placement of manufactured
home parks and subdivisions, shall have public utilities and facilities
such as sewer, gas, electrical and water systems located and constructed
to minimize or eliminate flood damage.
J.
Standards for areas of shallow flooding (AO/AH Zones). Located within the areas of special flood hazard established in § 350-604A are areas designated as shallow flooding. These areas have special flood hazards associated with base flood depths of one foot to three feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow. Therefore, the following provisions apply:
[Amended 12-8-2020 by Ord. No. 317-2020]
(1)
All new construction, substantial improvements, and reconstruction
due to substantial damage of residential structures, including all
equipment or mechanical items servicing the structure, shall have
the lowest floor (including basement) elevated above the highest adjacent
grade at least one foot above the BFE specified on the community's
FIRM (at least two feet if no BFE is specified).
(2)
All new construction, substantial improvements and reconstruction
due to substantial damage, of nonresidential structures, including
all equipment or mechanical items servicing the structure shall:
(a)
Have the lowest floor (including basement) elevated above the
highest adjacent grade at least one foot above the depth number specified
in feet on the community's FIRM (at least two feet if no depth number
is specified); or
(b)
Together with attendant utility and sanitary facilities, be
designed so that below the base flood level the structure is watertight
with walls substantially impermeable to the passage of water and with
structural components having the capability of resisting hydrostatic
and hydrodynamic loads of effect of buoyancy.
(3)
A registered professional engineer or surveyor shall submit a certification to the ESD, for review by the Floodplain Administrator, that the standards of this section, as proposed in § 350-601G, are satisfied.
(4)
Within Zone AH or AO, adequate drainage paths around structures
on slopes shall be required to guide floodwaters around and away from
proposed structures.
K.
Elevation certificates, construction. Construction within a Federal
Emergency Management Agency (FEMA) designated floodplain may not be
started until the applicant has provided an elevation certificate
that has been accepted by the appropriate County agency: the Flood
Commission or County Engineer. Designs for construction in the floodplain
shall be prepared by a professional engineer licensed in New Mexico.
L.
Elevation certificates, limits on liability. The acceptance of an
elevation certificate and related information will not constitute
a representation, guarantee or warranty of any kind or nature by Doña
Ana County or by any political subdivision, or by an officer or employee
of any of them, of the practicability or safety of any structure or
activity, and will create no liability upon or cause of action against
any public body, officer, or employee for damage that may thereby
result.
M.
Certificate of occupancy. Certificates of occupancy shall not be
issued until all applicable requirements of the currently adopted
Building Code and this chapter are met. Once a certificate of occupancy
is issued, a business registration shall be obtained for nonresidential
uses when required by law.
A.
General provisions. No grading shall be done within the County without complying with the requirements of this article and by an appropriately licensed contractor in the State of New Mexico. A grading permit shall be obtained from the County prior to the start of construction by an engineer licensed in the State of New Mexico. A copy of the grading permit shall be posted on site during hours of operation. See § 350-601H.
(1)
Work for which a grading permit has been issued under this article
shall be executed in conformance with the grading plan approved by
the ESD and shall not be abandoned or left incomplete. Failure to
continue significant work on a site once grading has begun may be
determined by the County to be an abandonment of the work required
by the permit, and such abandonment will constitute a violation of
this article.
(a)
The permittee is responsible for notifying the County within
seven days of stoppage for extenuating circumstances.
(b)
Having persons or equipment at a site, but not performing the
work, is not construed to be significant work.
(c)
Projects shall not be considered complete until notice of termination
has been made in accordance with all County and state regulations,
and the National Pollutant Discharge Elimination System requirements.
B.
Clearing and grubbing. Clearing and grubbing may require a grading
permit as determined by the County based on the following circumstances:
(1)
The grading of a driveway/access or road to a site;
(2)
To clear vegetation when work is necessary to allow proper preliminary
engineering on the site;
(3)
To provide security for a site from unauthorized grading or
dumping by clearing, loosening and berming the soil in a narrow band
around the perimeter of the property;
(4)
The construction of building pads; and
(5)
For such other purposes as the County may determine are proper
but do not entail reshaping or contouring of the land to any significant
degree.
C.
Exceptions from permits. Exceptions concern only the obligation to
apply for a permit, and do not relieve the landowner from complying
with the remaining provisions of this article. Grading permits will
not be required under the following circumstances:
(1)
Residential new construction, remodeling, additions or other alterations to existing structures are exempt from the requirements of § 350-601H provided that they meet the following conditions:
(2)
Commercial new construction, remodeling, additions or other alterations to existing structures are exempt from the requirements of § 350-601H provided that they meet the following conditions:
(a)
Less than 1,000 square feet of total land area and less than
six inches in depth is disturbed;
(b)
Average slopes across the property are greater than 4% and are
not disturbed; and
(c)
Existing drainage patterns are not changed on the property,
do not change the location of entrance or exit points or would not
increase the amount of stormwater runoff leaving the property.
(3)
Other exceptions, where the work is:
(a)
Routine agricultural or land management operations necessary
for cultivation of the soil of a farm or ranch (NMSA 1978, § 47-9-1,
Right to Farm Act);
(b)
Trenching operations for the construction or repair of pipelines
and other underground utilities; or
(c)
Small in depth, area or effect such as, but not limited to,
tree planting, intermittent and minor landscaping.
(4)
For the placement of a mobile home on lot, where permitted,
and where no grading is done.
D.
Erosion control plan (ECP). Any grading, construction, demolition,
or development requiring a permit or other form of approval under
any County ordinance shall have an approved ECP in place prior to
receiving a permit. The ECP may be separate documents, or incorporated
as part of required construction plans.
(1)
New development. Any development that requires a permit under
any County ordinance shall require an ECP be submitted consistent
with this section. Grading for all construction, including single-family
dwelling units, shall be limited to the building pad, pond, driveway,
and an additional five feet in all directions from these areas, unless
a need for additional area is demonstrated.
(2)
Existing conditions. If the condition of a property is determined
to pose a significant health threat because of its vulnerability to
erosion by natural forces due to the human development of the property,
or if the location of the property is near concentrations of vulnerable
populations (i.e., school children, ill or elderly persons), the owner
of such property will be required to submit an erosion control plan
(ECP) consistent with this section.
(a)
Determination. The initial determination that a property is
in such a condition may be made in writing by any law or code enforcement
or other County agent authorized to make such a determination and
is subject to review by the ESD.
(b)
Plan submission requirement. Upon receipt of the determination,
the property owner shall submit a proposed ECP within 30 days to the
County representative who made the determination. The ECP shall include
the BMPs presented within this section, or any other BMPs for eliminating
or mitigating the vulnerable condition of the property. The plan shall
include a proposed timeline for implementation.
(c)
Review of ECP. Upon receipt of the proposed ECP, the County
Engineer, or their designee, will determine if the ECP is sufficient.
If the ECP is determined to be insufficient, such determination and
reasons therefor shall be provided to the property owner in writing.
The property owner shall be given 10 working days to revise the ECP
and address the insufficiencies.
(3)
Exempt activities. Although the County encourages the use of
best management practices (BMPs) in all activities, the following
activities are exempt from the regulations and restrictions of this
section:
(a)
Regular agricultural operations covered by the Right to Farm
Act, NMSA 1978, §§ 47-9-1 through 47-9-7, including
cultivating, tilling, growing, and harvesting crops, and the raising
of farm animals or fowl.
(b)
Governmental activities during life-threatening situations,
other emergencies, or in connection with any officially declared disaster
or state of emergency.
(c)
Operations conducted by essential service utilities to provide
electricity, natural gas, oil and gas transmission lines, telephone,
water, and sewage during or to avoid service outages and emergency
disruptions.
(d)
Temporary use of unpaved roads and parking lots that generate
fewer than 20 vehicle trips per day for fewer than three successive
days.
(4)
ECP documentation. The following shall constitute the information
required within the ECP to describe the best management practices
(BMPs) proposed for the project or existing land surface. BMPs shall
be outlined and approved as part of the overall review of construction
drawings (or ECP if construction drawings do not apply) through the
ESD and CDD. The ECP shall be developed by a professional engineer
licensed in the State of New Mexico.
(a)
Name(s), address(es) and phone number(s) of person(s) responsible
for the preparation, submittal and implementation of the ECP, and
for the dust-generating operations.
(b)
A site plan or plat of survey of the site that describes the following. This may be combined with the grading plan if applicable. See § 350-605H.
[1]
The total disturbed area and the total area of the entire project
site, in acres or square feet, depending on the scale.
[2]
The operation(s) and activities to be carried out on the site.
[3]
All anticipated sources of fugitive dust emissions on the site.
[4]
Temporary drainage and ponding facilities to minimize soil erosion
and localized flooding of adjacent properties from water utilized
on site for development or dust control.
[5]
Delivery, transport, and storage area locations, types of materials,
and size of stockpiles for each type of material proposed for the
site.
(c)
A description of BMPs to be applied during all periods of dust-generating
operations to each of the fugitive dust sources on the site plan or
plat. At minimum, required information, including specific details,
are listed below.
[1]
If dust suppressants are to be applied, the type of suppressant;
method, frequency, and intensity of application; the number and capacity
of application equipment to be used; and any pertinent information
on environmental impacts and/or certifications related to appropriate
and safe use for ground applications shall be clearly indicated.
[2]
The specific surface treatment(s), and/or other BMPs utilized
to control material track-out and sedimentation, where unpaved and/or
access points join paved surfaces shall be clearly indicated.
[3]
For each fugitive dust source identified, at least one BMP shall
be implemented. The same BMP may be used for more than one dust-generating
activity. In addition, at least one auxiliary BMP shall be designated
as a contingency measure and be clearly described. Should the original
BMP prove ineffective, immediate and effective implementation of the
contingency measure shall obviate the requirement of submitting a
revised ECP.
[4]
BMPs to be implemented prior to any period of inactivity, due
to any reason other than extended rainfall of 10 days or more shall
be clearly indicated.
(d)
A description of BMPs or combination thereof to be used to minimize
the negative effects of water usage on site during the development
activities. All approved BMPs should be continued until final stabilization
is achieved.
(e)
The person responsible for implementing the objectives of the
ECP shall keep accurate records and document all activities in carrying
out the ECP. These records shall be made available upon request by
the County staff.
(5)
ECP review and acceptance. Review and acceptance of a proposed
ECP shall be the responsibility of the ESD, or other authorized County
staff members. Acceptance may be conditioned upon the implementation
of additional measures, actions, or other activities, in addition
to those included in the proposed ECP. Acceptance and issuance of
the building permit and/or construction permit, and the approval of
all outlined BMPs contained within the ECP shall constitute a mandate
that the accepted BMPs be implemented by the developer, operator,
builder, owner, and/or agents as part of construction activities.
(6)
Best management practices (BMPs). BMPs included within an ECP
required by this section may include any one or more of the following
measures:
(a)
Designing subdivisions or building sites to maintain existing,
predevelopment grades.
(b)
Watering disturbed areas on a regular, yet minimum, basis throughout
daily construction activities.
(c)
Applying palliatives or chemical soil suppressant/stabilizer
for idle construction periods.
(d)
Constructing snow and/or wind fences.
(e)
Reseeding or natural cover restoration within graded or disturbed
areas.
(f)
Grading for street and utility placement only as part of subdivision
construction.
(g)
Building some or all interior and perimeter cinder block, rock
walls, and retaining walls as part of the overall construction of
all subdivisions and not part of the individual building permit for
each lot.
(h)
Preserving natural vegetation during the construction phase
of buildings, excluding the building pad site.
(i)
Utilizing existing or natural vegetation as part of the required
landscaping for the site as elsewhere required within these design
standards, to limit grading activities, to promote water conservation,
and to reduce dust generation.
(j)
Installing vegetation or non-natural landscaping elements in
the latter part of construction to reduce the amount of disturbed
area and the potential for dust generation.
(k)
Implementing any other reasonable dust-suppressing agent or
activity.
(l)
Active operations in construction areas and other land disturbances:
[1]
Short-term BMPs:
[a]
Regularly scheduling wet suppression.
[b]
Applying dust suppressants in amounts and rates
recommended by the manufacturer and maintaining as recommended by
the manufacturer.
[c]
Incorporating temporary upwind windbreaks, including
fabric fences with the bottom of the fence sufficiently anchored to
the ground to prevent material from blowing underneath the fence.
[d]
Starting construction upwind and stabilizing disturbed
areas before disturbing additional areas.
[e]
Stopping active operations during high wind periods.
[2]
Long-term BMPs:
(m)
Specific construction guidelines. The following BMPs may be
incorporated in a proposed ECP to mitigate the effects of specific
activities:
[1]
Unpaved roadways:
[a]
Paving using asphalt, recycled asphalt, asphaltic
concrete, concrete, or double-penetration (consistent with subdivision
or zoning requirements).
[b]
Applying dust suppressants in amounts and rates
recommended by the manufacturer and maintaining as recommended by
the manufacturer.
[c]
Scheduling regular wet suppression.
[d]
Using traffic controls, including decreased speed
limits with appropriate enforcement, vehicle access restrictions and
controls, road closures and barricades, and off-road vehicle access
controls and closures.
[2]
Trucks hauling bulk materials on public roadways:
[a]
Properly securing tarps or cargo covering that
cover the entire surface of the load.
[b]
Applying dust suppressants in amounts and rates
recommended by the manufacturer and maintaining as recommended by
the manufacturer.
[c]
Maintaining six inches of clear, vertical distance
from the highest portion of the load to the lowest portion of the
truck beds.
[d]
Preventing leakage from the truck bed, sideboards,
tailgate or bottom dump gate.
[3]
Bulk material handling:
[a]
Using spray bars.
[b]
Adding wetting agents (surfactants) to bulk material.
[c]
Manually applying wet suppression.
[d]
Applying dust suppressants in amounts and rates
recommended by the manufacturer and maintaining as recommended by
the manufacturer.
[e]
Avoiding bulk material handling during high wind
conditions.
[f]
Reducing process speeds.
[g]
Reducing drop heights.
[4]
Industrial sites:
[a]
Paving roadways and parking areas with asphalt,
recycled asphalt, asphaltic concrete, or concrete.
[b]
Regularly scheduling vacuum street cleaning.
[c]
Scheduling regular wet suppression of unpaved areas.
[d]
Applying dust suppressants in amounts and rates
recommended by the manufacturer and maintaining as recommended by
the manufacturer.
[e]
Incorporating wind breaks or enclosures.
[f]
Increasing wet suppression applications during
high wind conditions.
[g]
Stopping or slowing active operations during high
wind conditions.
[5]
Demolition and renovation activities when asbestos-containing
materials are not present. If asbestos-containing material may be
present, all demolition or renovation activity shall be performed
in accordance with the federal standards referenced in 20 NMAC 11.64,
Emission Standards for Hazardous Air Pollutants for Stationary Sources.
In other instances, the following BMPs may be utilized:
[a]
Applying constant wet suppression on debris piles
during demolition.
[b]
Applying dust suppressants in amounts and rates
recommended by the manufacturer and maintaining as recommended by
the manufacturer.
[c]
Incorporating enclosures, curtains, or shrouds.
[d]
Using negative-pressure dust collectors.
[e]
Stopping demolition during high wind conditions.
[6]
Milling, grinding or cutting of paved or concrete surfaces.
[a]
Applying constant wet suppression.
[b]
Continuing ongoing cleanup of milled, ground or
cut material.
[c]
Dust suppression applied in amounts and rates recommended
by the manufacturer and maintained as recommended by the manufacturer.
[d]
Incorporating enclosures, curtains, or shrouds.
[e]
Using negative-pressure dust collectors.
E.
General nonconstruction activity standards.
(1)
Ground cover removal prohibited. No person shall disturb the
topsoil or remove ground cover on any real property within County
unless reasonable actions are taken to prevent generation of dust
caused by the disturbed condition.
(2)
Weed eradication and dust suppression.
(a)
Weed eradication is limited to removal of specific weeds; clearing
of the entire lot is prohibited.
(b)
Once weeds are removed or mowed, options for dust suppression
include watering, chemical suppressant application, or the expansion
of natural vegetation areas on the site. Expansion of natural vegetation
areas is encouraged.
(3)
Storage of materials and material transport. Actions shall be
taken to ensure that material storage, transport, and use areas and/or
practices with the potential of becoming or generating fugitive dust
and particulate matter shall be covered, moistened, compacted, or
otherwise treated to prevent fugitive dust creation.
F.
Engineering controls for stormwater and drainage runoff.
(1)
Authority. This section is adopted in accordance with the authority
granted by the New Mexico Water Quality Act, NMSA 1978, § 74-6-1
et seq., and the United States Clean Water Act. See 33 U.S.C. § 1251
et seq. Under the National Pollutant Discharge Elimination System
(NPDES) established by the Clean Water Act (33 U.S.C. § 1342),
Doña Ana County is required to obtain a permit for stormwater
discharges from its municipal separate storm sewer system (MS4). In
2007 the U.S. Environmental Protection Agency (EPA) issued an NPDES
Final General Permit (Federal Register Volume 72, Number 113, Page
32654) for small municipal separate storm sewer systems in New Mexico
under which the County has obtained permit authorization for its stormwater
discharges. The permit requires the County to adopt an ordinance that
prohibits non-stormwater discharges into the MS4 and requires construction
site operators to control erosion, sediment and wastes.
(2)
Purpose. The purpose of this section is to promote the elimination
or reduction of pollutants that enter the MS4 and to establish control
over discharges to and from the MS4. The purpose of this section is
to:
(a)
Maintain and improve the quality of surface water and groundwater
within the County limits;
(b)
Prevent the discharge of contaminated stormwater runoff from
industrial, commercial, residential, and construction sites into the
MS4, channels, watercourses, and waters of the U.S.;
(c)
Promote public awareness of the hazards involved in the improper
discharge of hazardous substances, petroleum products, household hazardous
waste, industrial waste, sediment from construction sites, and other
contaminants into the MS4, channels, watercourses, water, and waters
of the U.S.;
(d)
Minimize destruction of the natural landscape by reducing erosion
and sedimentation;
(e)
Control the adverse impacts associated with accelerated stormwater
runoff on natural channels, watercourses, and all MS4 structures due
to increased development and creation of new impervious surfaces;
(f)
Minimize erosion and degradation of channels and watercourses
and improve their condition where possible;
(g)
Respect, protect, maintain, and restore natural channels and
watercourses, wetlands, bosques, floodplains, steep slopes, riparian
vegetation, and wildlife habitat areas;
(h)
Facilitate compliance with state and federal standards and permits
by owners and operators of construction sites;
(i)
Enable the County to comply with all federal and state laws,
regulations and permits applicable to stormwater discharge; and
(j)
Protect the health and welfare of and improve the quality of
life for the citizens and residents of the County.
(3)
Administration and enforcement. The County Engineer designee shall administer and coordinate the implementation and enforcement of the provisions of § 350-605F, Engineering controls for stormwater and drainage runoff. Duties and responsibilities of the County Engineer shall include, but are not limited to, the following:
(a)
Ensure the provisions of MS4 are met, including but not limited
to dams, detention and retention basins, storm drains, outlets, pumping
stations, channels, watercourses, water, and waters of the U.S. within
the County;
(b)
Maintain and hold open for public inspection all records pertaining
to the provisions of this section;
(c)
Review and accept stormwater pollution prevention plans (SWPPP)
required by this section;
(d)
Supervise the operation and maintenance of the MS4 to ensure
its safe and effective functioning and notify the appropriate staff
of any required maintenance and/or repair work;
(e)
Establish and implement a program to locate and eliminate illicit
discharges and improper disposals to the MS4; and
(f)
Establish and implement a program to control pollutants in stormwater
discharges from construction activities.
(4)
General prohibitions.
(a)
No person shall introduce or cause to be introduced into the
MS4, channels, watercourses, water, or waters of the U.S. within the
County any discharge that is not composed entirely of stormwater.
(b)
It is an affirmative defense to any enforcement action for violation
of this section that the discharge was composed entirely of one or
more of the following categories of discharges:
[1]
Any authorized by and in full compliance with an NPDES construction
general permit (other than the NPDES permit for discharges from the
MS4);
[2]
Agricultural stormwater runoff;
[3]
Residential lawn watering, residential landscape irrigation,
or crop irrigation water;
[4]
A discharge from a diverted stream flow or natural spring;
[5]
Uncontaminated groundwater infiltration as defined in 40 CFR
35.2005(20) to the MS4;
[6]
Uncontaminated water from a foundation drain, crawl space pump,
footing drain, or sump pump;
[7]
A discharge from a potable water source not containing any pollutant
or material from the cleaning or draining of a storage tank or other
container;
[8]
An uncontaminated discharge from riparian habitat or wetland;
or
[9]
A discharge of de-chlorinated swimming pool water.
(c)
No affirmative defense shall be available under § 350-605F(4)(b) of this section if the discharge or flow in question has been determined by the County to be a source of a pollutant or pollutants to the MS4, channels, watercourses, water, or waters of the U.S. and written notice of such determination has been provided to the discharger.
(d)
The burden of proof that a discharge was composed entirely of one or more of the categories in § 350-605F(4)(b) and that it was not a source of a pollutant or pollutants to the MS4, channels, watercourses, water, or waters of the U.S. is upon the person responsible for the discharge.
(5)
Specific prohibitions and requirements. The specific prohibitions and requirements in this section are within, but do not limit, the general prohibition of all the discharges prohibited by the general prohibitions in § 350-605F(4).
(a)
No person shall introduce, or cause to be introduced, into the
MS4 any discharge that causes or contributes to causing the County
to violate a water quality standard, the County's NPDES permit, or
any state or federal issued discharge permit for discharges from the
County's MS4.
(b)
No person shall release, cause, allow, or permit the introduction
of any of the following substances into the MS4 or the channels, watercourses,
water, or groundwater within the jurisdiction of the County:
[1]
Used motor oil, antifreeze, hydraulic fluid, or any other motor
vehicle fluid;
[2]
Industrial waste or wastewater;
[3]
Hazardous waste, including household hazardous waste;
[4]
Domestic sewage or septic tank, grease trap, or grit trap waste;
[5]
Wastewater from a commercial car wash facility and commercial
vehicle washing, cleaning, or maintenance at any new or used automobile,
or other vehicle, dealership, rental agency, body shop, repair shop,
or maintenance facility;
[6]
Wastewater from the commercial washing, cleaning, deicing, or
other maintenance of aircraft(s);
[7]
Wastewater from a commercial mobile power washer or from the
washing or other cleaning of a building exterior where the wastewater
contains any soap, detergent, degreaser, solvent, other cleaning substance,
or a pollutant from the surface that is being cleaned, or that has
been produced by wash water applied at pressures elevated above the
distribution system pressure, or that is at a temperature that has
been elevated by induced heating;
[8]
Wastewater from commercial floor, rug, or carpet cleaning;
[9]
Wastewater from the wash down or other cleaning of pavement
that contains any soap, detergent, degreaser, solvent, other cleaning
substance, or a pollutant from the surface that is being cleaned,
or that has been produced by wash water applied at pressures elevated
above the distribution system pressure, or that is at a temperature
that has been elevated by induced heating; or any wastewater from
the wash down or other cleaning of any pavement where any spill, leak,
or other release of oil, motor fuel, or other petroleum or hazardous
substance has occurred, unless all quantities of such released material
have been previously removed;
[10]
Effluent from a cooling tower, condenser, compressor,
emissions scrubber, emissions filter, or the blow down from a boiler
containing harmful quantities of a pollutant;
[11]
Ready-mixed concrete, mortar, ceramic, asphalt
base material, hydromulch material, soil stabilizers, or runoff from
the cleaning of commercial vehicles or equipment containing, transporting,
or applying such material;
[12]
Contaminated filter backwash from a swimming pool,
fountain, or spa;
[13]
Fountain, swimming pool, or spa water that is
chlorinated (containing 0.1 milligram/liter or more of chlorine when
tested with a standard pool chlorine test kit) or contains pollutants,
to include any filter backwash water;
[14]
Discharge from water lines disinfected by super
chlorination or other means, if it contains any harmful quantity of
chlorine or any other chemical used in line disinfection;
[15]
Water from a water curtain in a spray room used
for painting vehicles or equipment;
[16]
Contaminated runoff from a vehicle wrecking yard;
[17]
Substance or material that will damage, block,
or clog the MS4;
[18]
Release from a petroleum storage tank (PST), or
any leachate or runoff from soil contaminated by a leaking PST, or
any discharge of pumped, confined, or treated wastewater from the
remediation of any such PST release, unless the discharge complies
with all state and federal standards and requirements;
[19]
Garbage, rubbish, yard waste, or other floatable
material;
[20]
Runoff, wash-down or other discharge from an animal
pen, kennel, or fowl or livestock containment area, unless the discharge
is authorized by an NPDES permit for a concentrated animal feeding
operation; or
[21]
Rubble, debris, tile, concrete, brick, asphalt
or other building material.
(c)
No person shall introduce, or cause to be introduced, into the
MS4, channels, watercourses, water, or waters of the U.S. any quantity
of sediment, silt, earth, soil, or other material associated with
clearing, grading, excavation, or other construction activities, or
associated with land filling, other placement, or disposal of soil,
rock, or other earth materials, in excess of what could be retained
on site or captured by employing erosion and sedimentation control
measures to the maximum extent practicable under prevailing circumstances.
(d)
No person shall connect a line conveying sanitary sewage, domestic
or industrial, to the MS4, or allow such a connection to continue.
(e)
Parking lot storm drain inlets shall be maintained free of garbage,
rubbish, yard waste, and other debris. Such material removed from
the inlets shall be disposed of in a container and shall not be allowed
to enter the MS4.
(6)
Release reporting and cleanup. The person operating any facility,
vehicle, or other source of spilling, leaking, pumping, pouring, emitting,
emptying, discharging, escaping, leaching, dumping, disposing, or
any other release of any of the following quantities of any of the
following substances that may flow, leach, enter, or otherwise be
introduced into the MS4, channels, watercourses, water, or waters
of the U.S., shall immediately notify the Mesilla Valley Regional
Dispatch Center at (575) 526-0795, or 911 and the County Engineering
Services Department and the County's Flood Commission on the next
business day:
(a)
An amount equal to or in excess of a reportable quantity of
any hazardous substance, as established in 40 CFR Part 302;
(b)
An amount equal to or in excess of a reportable quantity of
any extremely hazardous substance, as established under 40 CFR Part
355;
(d)
Any harmful quantity of any pollutant as defined in § 350-605F(5).
(e)
The immediate notification required by § 350-605F(6) include the following information:
[1]
The identity or chemical name of the substance released, chemical
classification, and whether the substance is an extremely hazardous
substance;
[2]
The exact location of the release, including any known name
of the waters involved or threatened, and any other environmental
media affected;
[3]
The time and duration of the release;
[4]
An estimate of the quantity and concentration (if known) of
the substance released;
[5]
The source of the release;
[6]
Any known or anticipated health risks associated with the release,
and, where appropriate, advice regarding medical attention that may
be necessary for exposed individuals;
[7]
Any precautions that should be taken as a result of the release;
[8]
Any steps that have been taken to contain and clean up the released
material and minimize its impacts; and
[9]
The names and telephone numbers of the person or persons to
be contacted for further information.
(f)
Within 14 days following such release, the person operating the facility, vehicle, or other source of the release shall submit a written report to the County Engineering Services Department containing each of the items of information specified above in § 350-605F(6)(e) of this section, as well as the following additional information:
[1]
The ultimate duration, concentration, and quantity of the release;
[2]
All actions taken to respond, contain, and clean up the released
substances, and all precautions taken to minimize the impacts;
[3]
Any known or anticipated acute or chronic health risks associated
with the release;
[4]
Where appropriate, any advice regarding medical attention necessary
for exposed individuals;
[5]
The identity of any governmental/private sector representatives
responding to the release; and
[6]
The measures taken, or to be taken, by the responsible person(s)
to prevent similar future occurrences.
(g)
Any release report required by a state or federal authority containing the information described in § 350-605F(5) and (6) of this section shall be adequate to meet County reporting requirements.
(h)
The notifications required by § 350-605F(5), (6), and (7) of this section shall not relieve the responsible person of any expense, loss, damage, or other liability which may be incurred as a result of the release, including any liability for damage to the County, natural resources, or any other person or property; nor shall such notification relieve the responsible person of any fine, penalty, or other liability which may be imposed pursuant to this chapter or to state or federal law.
(i)
Any person responsible for any release as described in § 350-605F(6) of this section shall comply with all state, federal, and any other local law requiring reporting, cleanup, containment, and any other appropriate remedial action in response to the release.
(j)
Any person responsible for a release described in § 350-605F(6) of this section shall reimburse the County for any cost incurred by the County in responding to the release, within 30 days of being invoiced by the County.
G.
Stormwater pollution prevention plan (SWPPP). Except for small construction activities with the waiver described in § 350-605G(15), all operators of a construction activity shall prepare a SWPPP for review and approval by the County. In cases where more than one person meets the definition of "operator," the persons may cooperate to prepare and implement a single, comprehensive SWPPP for the entire construction site and all phases of construction activity. The SWPPP shall be submitted to the County a minimum of 30 days prior to any land disturbance. For subdivision plans, a SWPPP shall be included with the final subdivision plan submittal. The County will review a SWPPP submittal or resubmittal and either accept it or provide a written notice of deficiencies within 30 days of the County receiving the SWPPP.
(1)
Contents of the SWPPP. The SWPPP shall be in accordance with
the requirements for the effluent limits, and the conditions applicable
to the State of New Mexico in the NPDES general permit for discharges
from construction activities that is effective at the time the SWPPP
is submitted to the County for review. The site map, or ECP, required
by the CGP shall consist of drawings that are a minimum of 11 inches
by 17 inches and sealed by a professional engineer in the State of
New Mexico or a CPESC. At a minimum, the SWPPP shall contain, but
is not limited to, the following:
(a)
Name, address, phone number, fax number, e-mail address and
SWPPP responsibilities of all operators using the SWPPP;
(b)
Name, address, phone number, fax number, and e-mail address
of the property owner(s);
(d)
Sequence and timing of activities that disturb soil, including
phasing to minimize the amount of area disturbed at one time;
(e)
Delineation and fencing or other protective measures for existing
vegetation and natural resources to be preserved;
(f)
Controls to minimize the disturbance of natural channels, watercourses,
and steep slopes;
(g)
Controls to minimize water and wind erosion during construction;
(h)
Controls to minimize sediment discharges in stormwater runoff
during construction;
(i)
Pollution prevention measures to minimize the discharge of pollutants
from on-site materials and wastes, including, but not limited to,
concrete truck washout, water from equipment and vehicle washing,
wheel wash water, washout of stucco or paint, any other wash water,
fuels, oils, other equipment and vehicle maintenance fluids, chemicals,
building materials, building products, construction wastes, rubbish,
landscape materials, fertilizers, pesticides, herbicides, detergents,
sanitary waste, and spills and leaks;
(j)
Controls to minimize off-site vehicle tracking of sediment onto
paved surfaces;
(k)
Sediment basins and/or turbidity treatment processes for drainage
locations that serve an area with 10 or more acres disturbed at one
time, as required by the CGP;
(l)
Temporary and permanent outlet structures and velocity dissipation
devices at stormwater discharge locations to protect against erosive
velocities during and after construction;
(m)
Practices to stabilize all disturbed areas, including off-site
areas that were disturbed in support of the construction activity,
when construction activity is completed (final stabilized) or has
halted (temporarily stabilized), and will not resume within 14 days;
(n)
Controls to remove suspended soil particles and other pollutants
in water discharged from dewatering activities, including discharges
from dewatering of trenches and excavations;
(o)
Using soil loss prediction models or equivalent and generally
accepted soil loss prediction tools, documentation that implementation
of the site-specific practices in the SWPPP will result in sediment
yields and flow velocities that, to the maximum extent practicable,
will not be greater than the sediment yield levels and flow velocities
from preconstruction, predevelopment conditions;
(p)
Inspection and maintenance procedures for best management practices
and other control measures; and
(q)
Signature and certification of each operator using the SWPPP,
in accordance with the CGP requirements for who is authorized to sign
and certify for the operator.
(2)
SWPPP inspections. Qualified personnel (provided by the operator
of the construction site) shall inspect all disturbed areas of the
construction site that are not stabilized and areas used for storage
of materials that are exposed to precipitation at the frequency required
in the CGP and its permit conditions for the State of New Mexico.
Disturbed areas and areas used for storage of materials that are exposed
to precipitation shall be inspected for evidence of, or the potential
for, pollutants entering the MS4, channels, watercourses, water or
waters of the U.S. Erosion and sediment control measures identified
in the SWPPP shall be observed by the operator to ensure that they
are operating correctly. Where discharge locations or points are accessible,
they shall be inspected to ascertain whether BMPs are effective in
preventing significant impacts to receiving waters or the MS4. Locations
where vehicles enter or exit the site shall be inspected for evidence
of off-site sediment tracking. A report shall be prepared for each
inspection and maintained with the SWPPP.
(3)
SWPPP maintenance. BMPs and other controls shall be maintained in effective, operating condition. If inspections described in § 350-605G(2) identify BMPs that are not operating effectively, the BMPs shall be repaired or replaced within 14 days and before the next storm event, whenever practicable. Sediment shall be removed from sediment traps, silt fence, sedimentation basins, and other sediment controls before it reaches half the height of the control, reduces the control capacity by 50%, or more frequently if specified in the SWPPP or by the control's manufacturer.
(4)
Stabilization. Within 14 days of stopping or completing construction activities, the construction site operator shall initiate stabilization in accordance with this chapter and the CGP. Temporary stabilization measures may be used if construction activity is anticipated to resume in the future. If temporary stabilization measures are used, inspection and maintenance requirements remain in effect until the criteria for final stabilization are met, regardless of whether construction activity resumes. A notice of termination [§ 350-605G(11)] will not be accepted by the County unless final stabilization is implemented.
(5)
If the construction project is completed, the final stabilization
shall meet the requirements in this chapter and the CGP, including
the permit conditions for the State of New Mexico.
(6)
Temporary stabilization measures in the SWPPP shall be appropriate
for and include, but are not limited to, the following:
(a)
Size of the disturbed area;
(b)
Soil type and susceptibility to wind and water erosion;
(c)
Slope steepness and slope stability;
(d)
Conveyance of stormwater runoff around or through the site without
causing erosion on the site or downstream;
(e)
Velocity dissipaters and other protection for temporary discharge
points to prevent erosion and damage to the downstream MS4, channel,
or watercourse;
(f)
Effective life of temporary stabilization measures in comparison
to length of time the disturbed area is anticipated to be without
construction activity; and
(g)
Inspection and maintenance procedures, at least monthly, to
ensure effectiveness of the stabilization measures until construction
resumes or final stabilization is established.
(7)
Final stabilization measures in the SWPPP shall be appropriate
for and include, but are not limited to, the following:
(a)
Soil type and susceptibility to wind and water erosion;
(b)
Slope steepness and its effect on erosion potential;
(c)
Structural measures to provide slope stability for any cut/fill
slope or natural slope disturb by construction that is steeper than
three horizontal on one vertical;
(d)
Permanent structures to convey stormwater around and across
slopes in a non-erosive manner;
(e)
For vegetative stabilization methods using live plantings (e.g., landscaping), inspection and maintenance procedures until stabilization is established and shown to be effective in satisfying the criteria for final stabilization. Vegetative stabilization methods using seed require 70% predevelopment plant coverage to achieve final stabilization. For landscaping requirements refer to § 350-507. A vegetative stabilization plan shall include:
[1]
Temporary controls (turf reinforcement mats, erosion control
blankets, etc.) with a minimum life of three years to stabilize the
surface until establishment of vegetation;
[2]
Seed mix appropriate for the climate and soil conditions;
[3]
Soil amendments and fertilizers as appropriate for soil conditions;
[4]
Annual (at a minimum) inspection and maintenance procedures
until criteria for final stabilization are met; and
[5]
An inspection report form in accordance with the permit conditions
for the State of New Mexico in the CGP; and
(8)
SWPPP revisions. The SWPPP shall be revised to provide different
or additional controls whenever a control is determined by the operator
or the County to be ineffective in controlling its targeted pollutant.
(9)
Notice of intent (NOI). All operators of construction activities
shall submit to the County a copy of the signed NOI and EPA's acknowledgement
of its receipt at least 14 days before commencing any soil-disturbing
activities at the construction site. A copy of the completed NOI shall
also be conspicuously posted near the main entrance of the construction
site. For linear projects, the NOI shall be posted at a publicly accessible
location near the active part of the construction project.
(10)
Operator changes. When the construction activity operator changes,
the new operator shall submit a revised SWPPP, signed certification
statement, and a copy of the new NOI to the County before starting
work at the site.
(11)
Notice of termination (NOT). All operators who have submitted
an NOI for construction activities shall submit to the County a copy
of the signed NOT within 30 days of one of the following conditions:
(a)
Final stabilization has been achieved on all portions of the
site for which the operator is responsible;
(b)
BMPs and other controls are in place and have passed to another operator who has submitted an NOI and SWPPP to the County, in accordance with the CGP and § 350-605G(10) through (11) of this section;
(c)
Coverage under an individual or alternative general NPDES permit
has been obtained; or
(d)
For residential construction only, the operator has established
temporary stabilization, including perimeter controls of the individual
lot, the lot has been transferred to the homeowner, and the operator
has given the homeowner written notification of the need for and benefits
of final stabilization.
(e)
The County will not accept a NOT without evidence of one of
the above conditions.
(12)
Appeal. An operator who submits a SWPPP for County review and
approval under this chapter and is denied approval may administratively
appeal a decision of the County Engineer to the BOCC. The appeal shall
be initiated by filing a written notice of appeal with the County
Engineer within 10 working days from the date of the final written
determination by the County Engineer. The notice of appeal shall cite
the factual basis for the appeal and the relief sought, and shall
be accompanied by relevant supporting documents and any required fee.
The BOCC may affirm, reverse, or modify the decision of the County
Engineer.
(13)
SWPPP and permit denial. The County may deny approval of a SWPPP
if it does not meet the requirements of this chapter or the CGP in
effect at the time the SWPPP is submitted to the County. In addition,
the County may deny approval of any County building permit, grading
permit, subdivision plat, site development plan, or any other County
permit, inspection, or approval necessary to commence or continue
construction, or to assume occupancy, in the absence of an approved
SWPPP required by this chapter, or whenever best management practices,
controls, and stabilization measures described in a SWPPP, or observed
upon a site inspection, are determined not to control and minimize
erosion, the discharge of sediment, or other materials and pollutants
associated with the construction activities.
(14)
Waivers. If the construction activity qualifies for an EPA waiver
of the CGP (refer to http://www.epa.gov/npdes/pubs/construction_waiver_form.pdf)
and is for a residential development, the County may waive the requirements
of this section; however, the construction site shall still comply
with the general and specific prohibitions. Specifically, the operator
shall ensure no harmful substances are introduced into the MS4, channels,
watercourses, water, or waters of the U.S. It is the operator's sole
responsibility to meet the requirements of the EPA waiver. To qualify
for the County waiver of this section, the operator shall submit a
copy of the EPA waiver certification and acknowledgement of its receipt
by the EPA to the County for review and acceptance. The County reserves
the right to require the construction activity to have a SWPPP even
if an EPA waiver is obtained. If the operator fails to meet the conditions
of a waiver, the operator shall be required to immediately comply
with this section. Failure to do so will constitute a knowing violation
of this section.
(15)
Flood control studies shall be performed by a qualified design engineer licensed within the State of New Mexico, and, if required, a completed drainage report shall be submitted to the County for approval (see § 350-605I below). The County will approve or require additional information or modifications to the report. Stormwater drainage reports, runoff reports and designs shall be approved before a grading permit is issued.
(16)
Analysis of any and all watershed areas affecting the proposed
site development and the design of flood control/drainage structures
shall be incorporated into the report.
(17)
Total surface runoff from the proposed improved site into existing
or future developments shall not exceed the runoff from the area of
land prior to development. The engineer may utilize retention/detention
ponds, swales, drainage channels, pumping facilities or any other
approved methods to restrict runoff to accomplish this task.
(18)
Surface and subsurface drainage shall not be altered or diverted
in any way that creates drainage or flooding to adjacent and/or downstream
properties.
(19)
Stormwater drainage improvements.
(a)
Construction plans and details for drainage structures shall
be included in the basic improvement plans for the proposed site development.
All drainage structures shall be designed to carry the one-hundred-year
stormwater runoff. All drainage ponds shall be designed to hold the
125% volume of the one-hundred-year storm runoff. All plans and details
for drainage structures shall be subject to review and approval by
the County.
(b)
The design engineer shall be responsible for showing all necessary supporting calculations, data and criteria on plans, specifications and if required, a drainage report with respect to flow capacities, structural soundness, public safety, etc. See § 350-605I below.
(c)
All drainage structures and construction methods shall conform
to the New Mexico Standard Specifications for Public Works Construction,
as amended. Drainage structures and construction methods shall also
conform to the NMDOT specifications for highway and bridge construction.
Drainage structures and construction details shall be clearly indicated
on the construction plans.
(d)
Drainage/flood control facility maintenance plans shall be submitted
as part of the drainage report.
(e)
All water containment structures which have water open to the
air shall empty either through percolation into the soil or through
outlet structures designed to ensure a controlled release of water
that will not cause flooding or erosion. An operation and maintenance
plan acceptable to the County shall be submitted for ponds that do
not empty within 72 hours.
(f)
Ponds with depths greater than three feet or slopes greater
than 4:1 shall be fenced.
H.
Grading and drainage plan. The purpose of the plan shall be to protect property from the effects of development. As required by this section, the grading and drainage plan shall address the control of drainage and erosion and shall calculate and analyze the measures necessary to adapt development to the existing soil characteristics and topography. This material should incorporate the terrain management, or grading, information necessary to address the requirements of the New Mexico Subdivision Act. The developer shall fulfill the proposals contained in the plan, and the plan shall be reviewed and approved by the appropriate reviewing agencies. All grading and drainage plans shall be certified by a professional engineer registered in the State of New Mexico and shall comply with § 350-604 above.
(1)
The requirement for grading permits may differ due to local
conditions of the land use, proposed site development, drainage patterns,
topography, soil conditions, soil type and other items. The principal
burden of designing a proper grading plan shall fall upon the landowner,
developer, contractor, or engineer concerned with the project. In
view of this circumstance, the following requirements have been developed
as an aid for operations covered by this article. Under no circumstances
should these conditions be construed to replace the basic requirements
of judgment, experience or competence that are a part of good engineering
and land development. The County, in order to assure that the correct
grading practices are followed as directed by this statement of purpose,
may impose any of the following requirements as part of the issuance
of a grading permit.
(3)
Soil erosion control. The requirements for soil erosion control measures depends largely upon the extent of the destructive and nuisance potentials due to erosion that may develop from the work to be performed. Thus, the need for erosion control measures is largely determined by prevailing winds, drainage patterns, soil characteristics and the proximity and potential hazards to downwind and downstream residences, businesses, thoroughfares and other facilities. See § 350-605D for erosion control plan requirements.
(4)
Earthwork for longer than 14 days. Where any project area is
to be exposed to the effects of wind or water for extended periods
of time, erosion control measures shall be continued and/or maintained
until natural growth comparable to that removed by the work has been
reestablished or until a stable, final development project has been
wholly completed.
(5)
Earthwork requirements. All permitted earthwork shall be designed
by a registered professional engineer licensed in the State of New
Mexico. An approved grading plan stamped and certified by a licensed
New Mexico professional engineer will generally govern in determining
the specific requirements of significant earthwork.
(a)
General.
[1]
Fill material will be free of material detrimental to construction
of stable fills.
[2]
Excavations will not be made close to property lines so as to
endanger adjoining property without providing support and protection
to prevent damage due to erosion, sliding or settlement.
[3]
Fills will not be placed where they can slide or wash onto the
property of others; nor will they be placed where they can cause encroachment
upon arroyos or other natural drainageways without provision of facilities
to assure the capacity of the drainageway as approved by the County.
[4]
Fill material placed above the top of an existing or proposed
surface with a slope steeper than three feet horizontal to one foot
vertical shall be set back from the top of the slope face at least
five feet.
[5]
Prior to placing fill on natural surfaces, all organic material
shall be removed and the natural surface shall be scarified to a depth
of 12 inches.
(b)
Compaction.
[1]
Load-bearing fills upon streets, lanes or public facilities
are to be located and shall comply with the requirements of the County
road standards as to the quality of fill materials, placement and
compaction. The plasticity index (PI) of structural fills shall not
exceed a value of 12 without specific recommendations from a New Mexico-registered
professional engineer.
[2]
Non-load-bearing fills shall be compacted to a minimum density
of 95% as per the American Society for Testing and Materials (ASTM
D-1557). Fills will be placed and compacted to minimize erosion and
produce a stable surface.
(6)
Other conditions. The following conditions may be imposed by
the County:
(a)
Flagmen may be required as part of the grading permit.
(b)
Any use of vibratory rollers shall be approved by the County.
(c)
The County shall be notified 24 hours in advance of any work;
such as placing curb, pavement, and storm sewer in County rights-of-way.
(d)
The County may impose hours of operation and truck routes to
be based on individual site locations, which shall be indicated on
the permit.
(e)
Limits on the amount and length of time materials may be stockpiled.
(7)
General design standards. Compliance with the following criteria
is essential to the proper preparation of a plan:
(a)
Runoff analysis shall take into consideration all contributing
runoff from areas outside the development. The analysis of storm runoff
from existing developed area outside the development shall be based
upon present land use and topographic features. Runoff from undeveloped
land outside the development shall be calculated using coefficients
appropriate for the current land use of the runoff source. When calculating
the runoff from land outside the development area, the land area included
shall be that area inclusive of the uppermost part of the watershed.
(b)
Flow patterns in undeveloped areas adjacent to the proposed
development shall be based on existing natural topographic features.
(c)
Average land slope in both developed and undeveloped areas may
be used in computing runoff.
(d)
Planning and design of drainage systems shall be such that flooding
problems are not transferred beyond the project's boundaries.
(e)
Outfall points shall be designed in such a manner that they
will not cause damage to areas downstream due to increased flooding.
Irrigation facilities shall not be used as outfall points.
(f)
Drainage easements or dedicated rights-of-way may be required where concentrated flow or ponding occurs. Acceptance of the rights-of-way shall be approved by the County; any dedication of drainage system components shall be agreed to and accepted by the County and included in the subdivision's disclosure statement per Article VIII.
(g)
Encroachment that impairs drainage easements or rights-of-way
shall be prohibited.
(h)
On-lot ponding shall be permitted on lots greater than 0.750
acre. For lots between 0.500 and 0.749 acre, on-lot ponding may be
permitted, provided the proposed on-lot slopes do not exceed 4% in
the developed area of the lot and the permeability of the soil allows
the pond to drain within 72 hours. For lots less than 0.500 acre in
size, alternative drainage plans on private lots may be approved as
part of an overall drainage plan. These alternative drainage plans
shall be certified by a professional engineer registered in the State
of New Mexico. The minimum depth of the pond shall be 18 inches. Secure
fencing shall be required if the depth of the pond exceeds three feet,
unless the pond is designed as an amenity with slopes less than 4:1.
Fencing requirements may be waived if an alternate drainage design
demonstrates safe conditions and is approved by the County. The ponds
shall be maintained by the property owners and shall be enforced through
any drainage maintenance agreement concerning drainage from the public
right-of-way (see sample forms in Appendix A).[1] The side slopes (rounded to the nearest whole number)
shall be treated with the applications found in Table 6.16, Treatment
Applications for Ponding Areas.
Table 6.16 Treatment Applications for Ponding Areas
| |
---|---|
Side Slope
|
Typical Treatment Required or Other Acceptable Applications
|
Side slope 2:1
|
Grouted rock, concrete, or wire-tied rip-rap
|
2:1 < Side slope < 3:1
|
Hand placed rip-rap
|
Side slope < 3:1
|
Permanent best management practices (BMPs), such as vegetation,
landscape rock, etc. are required
|
(i)
All ponding should be designed to complement the landscape and
return to native conditions.
(j)
Community ponding areas may be taken over by Doña Ana
County upon mutual agreement between the developer and the County.
The developer shall demonstrate that a proposed ponding area is in
good operational condition. Maintenance schedules shall be submitted
as well as support documentation indicating the source of water that
is routed to ponding areas. Design considerations shall take into
account location, depth, side slopes, erosion control, maintenance,
access, landscaping, and fencing. The proposed ponding areas shall
be reviewed and accepted by ESD and/or the Flood Commission prior
to moving forward to the BOCC. The ponds shall be offered for dedication
and considered for acceptance by the BOCC and shall be subject to
a one-year warranty period. The agreement shall be approved prior
to final plat approval.
(k)
The primary purpose of streets is the safe conveyance of vehicular
traffic. Any runoff carried by a street shall comply with the requirements
of Table 6.18, Street Capacity Criteria.
(8)
Wind erosion control shall be required per § 350-605D(4)(c).
I.
Drainage report. A drainage report shall be required for all developments
that meet any of the following criteria:
(1)
The entire development, or a portion thereof, lies within a
FEMA special or flood hazard area or other flood hazard areas as determined
by the DAC Office of the Flood Commission;
(2)
Grades within the area to be developed in excess of 4%; or
(3)
A major arroyo, stream, or channel exists within the area to
be developed.
(4)
Required calculations, analysis and documentation:
(a)
Peak flow from all off-site tributary drainage areas;
(b)
Peak flow within the proposed development for all on-site drainage
basins for pre- and post-development;
(c)
Closed sub-basin analysis, including identification of water
into or out of sub-basins;
(d)
Potential drainage problems that are anticipated within the
development and downstream from the development;
(e)
Effects of ten-year and one-hundred-year twenty-four-hour storm
events;
(f)
Routing and cumulative flows for ten-year (if applicable) and
one-hundred-year twenty-four-hour storms at all critical points in
the drainage system, which may include points of intersection, change
of flow, change of slope, change of structural elements, and any other
critical point in the drainage system;
(g)
Function, analysis and capacity calculations for all drainage
system components that are part of the development proposal, which
may include inlets, storm drains, channels, streets, culverts, ponds,
swales, dams, berms, etc.; and
(5)
Overall drainage area boundaries and drainage subarea boundaries
depicted on a map.
J.
Runoff analysis method.
(1)
Developments of less than three acres. Runoff analysis for developments
of less than three acres can be based on general runoff coefficients
for valley and mesa areas. The runoff coefficient is a value used
to approximate the amount of runoff a developer or home builder shall
retain on-site to maintain existing drainage characteristics. The
following simplified approach may be used, but other methods may also
be considered.
(c)
Calculate the impervious area of the lot to be developed in
square feet.
(d)
Find required storage volume by multiplying the impervious area
(square feet) by the runoff coefficient (inches) and a conversion
factor of one foot/12 inches.
[1]
Area x Runoff Coefficient x Conversion Factor = Runoff Volume.
(e)
Indicate on the construction plans how the required runoff volume
will be controlled on site. Include details on asphalt and lot grades,
walls and/or berms that will control or direct runoff, and method
of overflow of the storage area.
(f)
Acceptable types of drainage structure are listed below; however,
other methods may be acceptable upon approval by the County.
[1]
Open ponding. Open retention ponds are recommended in areas
that have good percolation of water into the soil. Open ponds offer
the maximum amount of storage for a given land area. The minimum depth
shall be 18 inches, and the pond shall be located a minimum of five
feet from adjacent property lines and 10 feet from any structures.
[2]
French drain. Acceptable in areas that have poor percolation
rates, i.e., areas where clay is present. A french drain shall be
used only to provide increased percolation rates for runoff. French
drains shall have an open pond above rock level with a minimum clearance
of 12 inches.
[3]
Underground storage. Underground storage is recommended in areas
with good percolation and limited space. Credit is given for the open
volume only; no credit is given for rock voids. No credit will be
given for "rock ponds." Some acceptable products include, but are
not limited to, perforated CMP, perforated HDPE, Rainstore©,
infiltrator systems, etc. Designs shall include a method to maintain
the structure's effectiveness.
(2)
Developments equal to or greater than three acres: Runoff analysis
for development equal to or greater than three acres shall be based
on the Soil Conservation Service (SCS) Method as modified for New
Mexico, or other method approved by the County. When utilizing the
SCS Method, the NRCS Type II-75 storm distribution (see Table 6.17,
NRCS Type II-75 Storm Distribution) shall be used. Other storm distributions
may be accepted by the responsible departments if valid written justification
is provided by the applicant's engineer. This storm distribution assumes
75% of the total rainfall occurs within the sixth hour of a twenty-four-hour
rainfall event. Furthermore, the following limitations apply to the
SCS Method:
(3)
Overland flow portions of time of concentration are to be calculated
for a maximum reach length of 300 feet.
Table 6.17 NRCS Type II-75 Storm Distribution
| |||
---|---|---|---|
Time
(hours)
|
Fraction of 24-hour Rainfall
(Type 11-75)
|
Time
(hours)
|
Fraction of 24-hour Rainfall
(Type 11-75)
|
0.00
|
0.0000
|
7.00
|
0.8740
|
1.00
|
0.0080
|
7.50
|
0.8875
|
2.00
|
0.0177
|
8.00
|
0.8977
|
3.00
|
0.0301
|
9.00
|
0.9122
|
4.00
|
0.0475
|
10.00
|
0.9923
|
4.50
|
0.0591
|
11.00
|
0.9318
|
5.00
|
0.0754
|
12.00
|
0.9392
|
5.25
|
0.0863
|
14.00
|
0.9524
|
5.50
|
0.1016
|
16.00
|
0.9640
|
5.75
|
0.1280
|
18.00
|
0.9743
|
6.00
|
0.7895
|
20.00
|
0.9836
|
6.25
|
0.8323
|
22.00
|
0.9922
|
6.50
|
0.8516
|
24.00
|
1.0000
|
6.75
|
0.8644
|
K.
Construction plans. A registered professional engineer licensed in
the State of New Mexico who has experience and demonstrated competence
in this area shall certify all construction plans. A traffic control
plan shall be submitted and approved by the Engineering Services Department
prior to issuance of a construction permit. The construction plans
shall be submitted on twenty-four-inch-by-thirty-six-inch sheets,
and shall contain at least the following:
(1)
General requirements. Construction plans shall include, at a
minimum:
(a)
Title sheet;
(b)
Copy of proposed subdivision plat, showing existing and proposed
easements and rights-of-way;
(c)
Copy of final grading and drainage plan;
(d)
Plans and profiles for all components of the storm drainage
system proposed to be constructed within and adjacent to the subdivision/development;
(e)
Details for all drainage system components as required to define
structural or construction methods and requirements;
(f)
General construction notes;
(g)
Detail sheets;
(h)
Traffic control plan, to include construction signing, permanent
signing and pavement markings; and
(i)
A subdivision schematic indicating proposed permanent roadway
signage.
(2)
Plan and profile details. Construction drawings shall include,
at a minimum:
(a)
North arrow and scale;
(b)
Subdivision/development limits and individual lot lines, existing
and proposed easements and rights-of-way;
(c)
All street and paving improvements, including street names,
and widths;
(d)
Existing and proposed utilities affected by the proposed construction;
(e)
Existing ground surface and proposed ground surface grades clearly
delineated;
(f)
Project benchmarks;
(g)
Information on proposed pipes and culverts, including:
[1]
Stationing;
[2]
Profile;
[3]
Size of pipes;
[4]
Grades of pipes;
[5]
Length between manholes or other access points;
[6]
Construction details, station numbers, invert elevations and
top elevations for all inlets and outlets, manholes, and all connections
to existing drainage systems; and
[7]
Construction notes, including pipe composition and specification
references as required; and
(h)
Details on proposed open channels, including:
[1]
Stationing;
[2]
Profile indicating grade of invert of channel, top of lining
(if any), and adjacent ground grade;
[3]
Typical cross sections;
[4]
Rip-rap details with rock gradation requirements;
[5]
Lining details;
[6]
Structural details; and
[7]
Construction notes and specification references as required.
(3)
Drainage maintenance agreement. This agreement defines the responsibilities
and requirements of the individuals or groups responsible for maintaining
all elements of the drainage system, using the sample format provided
Appendix A.[2] The agreement shall be substantially in the form provided
in the sample; however, it may be modified as needed to accommodate
the specific drainage system as required by the Flood Commission.
L.
Geotechnical analysis. A geotechnical analysis will be provided,
unless otherwise exempted by this article, to assess the properties
of soils within project areas, shall, following all applicable ASTM
standards, be submitted to ESD, and shall contain, at a minimum, the
following criteria:
(1)
A detailed description of the project area, including proposed
land use, terrain, slopes, drainage patterns and vegetation.
(2)
A detailed description of the geology found in the general area
of the project site.
(3)
An outline and description of the methodology and procedures
used in the sampling of soils within the project area.
(4)
A site vicinity map of appropriate scale indicating the location
of the project.
(5)
A site map of appropriate scale indicating the location of the
test borings.
(6)
A boring log for each test hole location showing the depth of
each soil sample retrieved, a visual description of each soil sample
retrieved, the method of soil sampling, the thickness of each soil
layer encountered, standard penetration test results and any other
applicable information gained during sampling.
(7)
A summary of the laboratory analysis of each soil sample collected,
to include gradation, Atterburg limits, moisture content, etc.
(8)
A summary of the soil classifications determined for each soil
sample.
(9)
A summary of the soil bearing capabilities found within the
project area, if applicable; results of percolation test rates within
the project area, if applicable.
(10)
Foundation recommendations for structures within the project
area, if applicable.
(11)
Pavement design recommendations within the project area, if
applicable.
(12)
Recommendations for earthwork practices within the project area,
to include compaction, soil blending, over excavation, benching, etc.
(13)
Recommendations for inspection and material testing frequencies
during the construction phases of the project.
(14)
Structures built on unacceptable materials shall require an
alternative design, to include geotextiles, geogrid, limestone stabilization
or other acceptable process approved by County Engineering Services.
M.
Driveway culverts and road drainage requirements. There are two systems
that will provide stormwater control in and along a roadway: curb
and gutter designs and roadway swales. Alternate systems are encouraged
and may be approved by the County Engineer. All systems shall be designed
to provide a four-foot shoulder/walking path that is not on the roadway
surface or in the stormwater runoff flow area necessary for a ten-year
storm event.
(1)
Curb and gutter. The developer may use curb and gutter to control
storm runoff flows; see the Design Drawings. In addition, swales behind
the curb shall be used to contain a minimum volume of stormwater equal
to the volume of increased runoff from the site due to development
of the roadway. Erosion control and energy dissipation measures shall
be designed and installed at the boundary of any development using
curb and gutter with outlets for stormwater flows onto an unlined
surface.
(2)
Roadway swales. Roadway swales may be used to convey and/or
store stormwater flows along the roadway, under the following conditions:
(a)
Swales shall be designed for velocities not to exceed those
listed in Table 6.24, Maximum Velocity of Unlined Channels and Swales.
(b)
Stormwater storage requirements for swales shall be based on
the fully developed stormwater flow conditions of the development.
Roadway swales with a longitudinal slope of less than 1/2% shall be
constructed within an easement outside the road right-of-way, and
shall be sized to contain a minimum volume that represents the increase
in stormwater runoff due to development. Swales shall also be designed
to control the increased runoff due to roadway development.
(c)
Conveyance capacities of swales shall be based on the developed flow and any existing or anticipated exterior flows entering the development. Swales shall be designed as channels per § 350-605N. Underground drainage systems may be used if the inlets will not present a maintenance problem and concentrated flows at any outlet will not cause any damage to adjacent lands. Swales for roadway gradients of 0.0051 foot per one foot or greater shall be analyzed and designed for conveyance of the maximum storm runoff (one-hundred-year storm) from the development site and any existing external flows routed through the development.
(d)
For swales that require conveyance of flow to maintain existing
drainage patterns, the driveway crossings shall be incorporated in
the roadway/swale drainage system. Driveway crossings may consist
of a minimum of a "dip section" with six-inch-thick concrete (concrete
used in the right-of-way shall have a minimum strength of 3,000 pounds
per square inch). Driveways subjected to nonresidential traffic shall
be designed and properly reinforced. The dip section shall be shown
to have adequate cross-sectional area and slope to convey the ten-year
storm. Other methods to convey storm runoff across driveways may be
used if the design is reviewed and approved by the County Engineer.
The depth for a dip section shall be a minimum of eight inches.
(e)
Ponds located on private property that are not designed to convey
storm runoff to another location are not required to be interconnected
through driveway crossings. They may interconnect, provided that no
landowner is required to "store" any additional stormwater on his/her
property, without the landowner's consent. (A purchaser of property
with stormwater storage requirements made by the developer of the
property as part of the development approval process shall be responsible
to meet the development conditions of stormwater drainage).
(3)
Storm drains and storm inlets. Storm drains and inlets shall
be of sufficient capacity to adequately convey the expected runoff
from the one-hundred-year twenty-four-hour storm. The storm drain
system and subsequent storm inlets shall commence at all locations
where the allowable street capacity is exceeded or at locations where
ponding of water is likely to occur. See Table 6.18, Street Capacity
Criteria.
Table 6.18 Street Capacity Criteria
| |||
---|---|---|---|
Street Type
|
Storm Type
| ||
10-Year, 24-Hour1
|
100-Year, 24-Hour1
| ||
Local
| |||
|
Roadway swales
|
Collected flow spread shall allow for 1 10-foot lane clear of
runoff2
|
Collected flow shall be contained within right-of-way and/or
easements
|
|
Cross flow
|
N/A
|
Cross flow not to exceed 12 inches deep above pavement surface3
|
|
Curb and gutter
|
Collected flow spread shall allow for 1 10-foot lane clear of
runoff2
|
Collected flow shall be contained within the curb and gutter;
cross flow not to exceed 6 inches deep above pavement surface or gutter
flow line3
|
Collector
|
Collected flow spread shall allow for 1 10-foot lane clear of
runoff. Crossing flow cannot exceed 6 inches deep above pavement surface
or gutter flow line3
|
Collected flow shall be contained within the curb and gutter;
cross flow not to exceed 6 inches deep above pavement surface or gutter
flow line3
| |
Arterial
|
Collected flow spread shall allow for 2 10-foot lanes clear
of runoff; no crossing flow allowed on surface
|
Collected flow within the curb and gutter cannot exceed 6 inches
deep above gutter flow line; no cross flow allowed at arroyos and
channel crossings; cross flow not to exceed 3 inches deep at street
intersections3
|
Notes:
| |
(1)
|
Flows exceeding these criteria shall be removed from the street
and conveyed by a storm sewer system or open channel system.
|
(2)
|
Flow collected in roadway swales shall be controlled in such
a way as not to threaten the integrity of street pavements.
|
(3)
|
Cross flow velocities shall be maintained at less than five
feet per second.
|
(a)
Minimum pipe diameter. The minimum allowable pipe size to be
used in storm drains shall be a minimum of 24 inches in diameter.
(b)
Minimum culvert cover. The minimum culvert cover shall be two
feet, but additional cover may be required by design.
(c)
Allowable pipe materials/applications for storm drains. PVC,
HDPE, RCP Class III, IV or V and CMP application is dependent on soil
conditions and pipe application. All pipes and conduits shall be designed
to withstand all anticipated structural loads. NMDOT standards shall
be the minimum used.
(d)
Allowable pipe materials for culverts. RCP and CMP applications
are dependent on soil conditions and pipe application. All pipes and
conduits shall be designed to withstand all anticipated structural
loads. NMDOT standards shall be the minimum used.
(e)
Manhole spacing. The maximum allowable spacing between manholes
or other provisions for clean-outs shall not exceed those listed in
Table 6.19, Allowable Manhole Spacing.
(f)
All pipe systems shall be pressure tight.
Table 6.19 Allowable Manhole Spacing
| |
---|---|
Pipe Diameter
(inches)
|
Maximum Allowable Spacing Between Manholes
(feet)
|
24 to 36
|
400
|
42 to 60
|
500
|
Greater than 60
|
750
|
Note: Additional manholes will be required with
a change in vertical or horizontal deflection greater than the manufacturer's
installation specifications.
|
(g)
Calculation flow capacities in drainage conduits. The capacities
of conduits shall be computed using Manning's formula with flow nomographs,
recognized accepted standards or computer analysis. The value of the
roughness coefficient (n) to be used shall not be less than those
specified in Table 6.20, Values for n for the Manning Formula. Included
in the table are roughness coefficients that can be used in open channel
flow calculations. The average full-flow velocity in conduits shall
not be less than two feet per second. See Table 6.20, Values for n
for the Manning Formula.
Table 6.20 Values for n for the Manning Formula
| ||
---|---|---|
Flow Condition
|
Roughness Coefficient (n)
| |
Conduits
|
Smooth metal
|
0.010
|
Plastic pipe, PVC, HDPE
|
0.012
| |
Ordinary concrete
|
0.013
| |
Concrete pipe
|
0.015
| |
Corrugated metal pipe
|
0.023
| |
Natural channels
|
Clean, straight, no pools
|
0.029
|
As above, with weeds and stones
|
0.035
| |
Winding, pools and shallows, clean
|
0.039
| |
Very weedy
|
0.040
| |
Lined channels
|
Smooth finish
|
0.015
|
Brick, dressed stone
|
0.016
| |
Smooth earth
|
0.018
| |
Unfinished
|
0.020
| |
Firm gravel
|
0.020
| |
Mortared stone
|
0.020
| |
Dry rubble or rip-rap
|
0.035
| |
Rough asphalt
|
0.016
| |
Smooth asphalt
|
0.013
|
Note: Or currently published values as approved
by ESD.
|
(h)
Storm drainage inlets. Storm drainage inlets may be a combination
curb/gutter or curb opening inlet or off-road sump inlet. Combination
curb/gutter inlets or off-road sump inlets shall be used at all points
where ponding or sump conditions exist. The theoretical capacity and
spacing of storm inlets will be analyzed using the criteria outlined
in this article. The allowable capacity will be determined using the
reduction factors listed in Table 6.21, Inlet Reduction Factors. These
reduction factors compensate for debris plugging, pavement overlaying,
variations in design assumptions and other factors that decrease capacities.
The size of outlet pipes from stormwater inlets shall be based upon
the theoretical capacity on the inlet, but in no case shall pipes
be smaller than 24 inches in diameter. See Table 6.21, Inlet Reduction
Factors.
Table 6.21 Inlet Reduction Factors
| |
---|---|
Inlet Type
|
Percentage of Theoretical Capacity Allowed
|
Combination curb and gutter opening with grate
|
65%
|
Curb opening only
|
85%
|
Grate only
|
50%
|
Notes:
| |
(1)
|
Computations for storm drain and inlet design capacities shall
be submitted as part of the storm drainage report.
|
(2)
|
The details of the proposed storm drain system, inlets and manholes
shall be addressed in the drainage report and shown on the construction
drawings.
|
(3)
|
Theoretical flow capacities shall be reduced by the reduction
factors outlined in this table to obtain design flow capacities.
|
(4)
Crossing structures and culverts.
(a)
Crossing structures and culverts shall be sized to comply with
the requirements of Table 6.18, Street Capacity Criteria, and shall
convey the one-hundred-year storm through the structure with additional
design that provides for overflow capacity in the event that the culverts'
capacity is reduced due to trash or debris accumulation. All drainage
structures shall be designed with emergency overflow that will help
convey the major storm event. In no case shall a crossing structure
or culvert have a diameter of less than 24 inches. In determining
the amount of overflow required, the following capacity credit in
Table 6.22, Capacity Credit for Structures, shall apply:
Table 6.22 Capacity Credit for Structures
| ||
---|---|---|
Cross-Section Area of Structure
|
Capacity Credit Percentage of Full Flow Capacity
|
Percentage of Major Storm Flow To Be Added to Culvert
Capacity or Considered as Overflow
|
Less than 20 square feet
|
0%
|
100%
|
20 square feet or greater
|
50%
|
50%
|
(b)
The emergency overflow onto streets shall be taken into account
when analyzing storm runoff and allowable street capacities for the
major storm. The following design criteria shall be used for all culvert
designs:
[1]
Culvert. All inlet and outlet structures shall be designed to
convey the flow of water and address traffic loading and debris at
all stages of flow.
[2]
Inlets. Culvert inlets shall be designed to minimize entrance
and friction losses. Inlets shall be either flared-end sections or
headwalls with wing walls. Projecting ends will not be acceptable.
Provisions shall be made to resist possible structural failure due
to hydrostatic uplift forces.
[3]
Outlets. Culvert outlets shall be designed to avoid sedimentation,
undermining the culvert or erosion of the downstream channel. Outlets
shall be either flared-end sections or headwalls with wing walls.
Additional outlet control in the form of rip-rap, channel shaping,
etc., may be required where excessively high discharge velocities
occur.
[4]
Slopes. Culvert slopes shall not allow silting, excessive velocities
or scour. The minimum slope of culverts shall be limited to 0.5%.
[5]
Headwater. The headwater-to-diameter ratios should not exceed
the criteria in Table 6.23, Recommended Maximum Headwater-to-Diameter
Ratios. Any ponding above culvert entrances is unacceptable. Such
ponding may cause property or roadway damage, culvert clogging, saturation
of fills, detrimental upstream deposits, or inundate existing or future
utilities or structures.
Table 6.23 Recommended Maximum Headwater-to-Diameter Ratios
| |
---|---|
Storm Frequency
|
HW/D
|
10-year
|
1.0
|
100-year
|
1.25
|
[6]
Tailwater. The height of tailwater at outlets shall have a headwater-to-diameter
ratio of less than 1.0.
[7]
Dip section and low water crossings shall be concrete and designed
in accordance with the criteria in Table 6.18, Street Capacity Criteria,
and shall provide for erosion protection at the edges of pavement.
(5)
Roadway drainage best management practices.
(a)
Description. Best practice will infiltrate stormwater into plantings
and soil, and safely release remaining water.
(b)
Methods. Best practice will filter stormwater through soil media
and plant roots, then release treated stormwater runoff into the landscape
(e.g. pasture, native vegetation areas, plantings, and permeable areas)
and storm drain system. Best practices should be coordinated with
EDS and CDD staff.
[Amended 11-14-2017 by Ord. No. 294-2017]
N.
Open channels. Channel capacities shall be computed using the Manning
formula for uniform flow. Open channels shall be designed for a one-hundred-year
storm with analysis showing the effects of the ten-year storm. Channels
shall have subcritical flow characteristics, be wide and natural in
appearance and functional. Analysis and proposed solutions for anticipated
erosion problems shall be in the drainage plan. Channels shall be
designed to avoid flows at or near critical depth.
(1)
Hydraulics. The type of channel cross sections shall be most
suited to the location and use. The drainage report and design hydraulics
of flow in channels shall include analysis of the hydraulics indicating
the following parameters for existing and proposed channels and drainageways:
(a)
Flow cross-section geometry for each different configuration
of proposed channel shape in critical areas and channels left in their
natural state;
(b)
Flow cross-sectional area;
(c)
Wetted perimeter;
(d)
Hydraulic radius;
(e)
Manning's roughness coefficient (n);
(f)
Flow velocity;
(g)
Design discharge;
(h)
Bed slope;
(i)
Froude number; and
(j)
Freeboard requirements.
(2)
Erosion. All channels shall be designed with the proper and adequate erosion control features and shall comply with § 350-605D.
(3)
Water surface profile. A water surface profile for the major
storm runoff shall be computed for all channels and clearly shown
on final drawings submitted for approval. Computations for the water
surface profile shall utilize standard backwater methods, taking into
consideration all losses due to velocity changes, drops, bridge and
culvert openings, and other obstructions. Computations shall be submitted
with the final design plan. The energy gradient line should also be
computed and shown on the final drawings.
(4)
Channels. Mild slope channels shall be classified as channels
whose slope maintains flows with a Froude number of less than 0.8.
Drops may be used to maintain this criterion. Unlined channels can
be used when the Froude number is less than 0.8. Drops may be used
to maintain this criterion. Unlined channels can be used when the
Froude number is 0.8 or less. Maximum velocities of unlined channels
shall follow the requirements in Table 6.24, Maximum Velocity of Unlined
Channels and Swales. Side slopes of 4H:1V shall be considered a normal
minimum. Any side slope steeper than this will require approval from
the County.
Table 6.24 Maximum Velocity of Unlined Channels and Swales
| ||
---|---|---|
Classification of Soils
| ||
Cover
|
Erosion Resistant (clay) Soil
(feet per second)
|
Easily Erosive (sandy) Soil
(feet per second)
|
No cover, dirt lines
|
4.0
|
2.5
|
*Buffalo grass, bluegrass, smooth brome, blue grama, native
grass mix
|
7.0
|
5.0
|
*Lespedeza, lovegrass, kudzu, alfalfa, crabgrass
|
4.5
|
3.0
|
Note: Table data assumes detailed soils analysis.
| |
*
|
Grass cover assumed to be a good stand and well maintained
|
(5)
Lined channels. Channels exhibiting hydraulic characteristics
that result in a Froude of 0.8 or more during the ten-year or one-hundred-year
storm will require stabilization in the form of a lining. These channels
are defined as those exhibiting characteristics that would require
lining of the channel to ensure structure stability, to achieve the
desired design life of the channel, and to protect areas adjacent
to the structure. Contributing factors in the analysis of channel
lining requirements include an urban setting, bed slope, flow rate,
soil type and stability, and any flow conditions that cause velocity
changes.
(6)
Lining materials. Lining material shall be composed of one of
the following:
(a)
Concrete of sufficient strength and thickness to support all
design loads, including maintenance equipment, with a minimum cross
section of concrete six inches thick, 3,000 pounds per square inch
minimum compression strength. Roughening of concrete surfaces is encouraged.
Roughening may be accomplished by use of suitable methods approved
by the County Engineer.
(b)
Asphalt of sufficient strength (including base materials) to
support all anticipated design loads, including maintenance equipment.
Asphalt lining shall be of a mix design that will resist damage due
to erosion for the design life of the lining, which shall be 20 years.
(c)
Rip-rap set in concrete or mortar shall have the rock size and
weight sufficient to resist displacement of the rock by the energy
present in the flow of the one-hundred-year storm. Rip-rap may be
stabilized by grouting, can be set in concrete, or may be wire-tired.
Standard gabions may be used to stabilize soil under some conditions.
(d)
Other material, such as soil cement, may be used when approved
by the County Engineer.
(7)
Depth of flow. Considering velocities involved and land area
needed for drainage easements, the depth of flow shall be kept to
a minimum. The maximum design depth for the one-hundred-year storm
runoff shall be four feet in open channels, unless otherwise authorized
by the County Engineer.
(8)
Freeboard. The design of channels shall take into account requirements
for freeboard to provide a factor of safety against splash and hydraulic
jump phenomenon.
(a)
For conditions of uniform flow, the minimum lined elevation
shall include freeboard above the flow surface of the one-hundred-year
storm and be calculated using the following equation:
Freeboard (in feet) = d/4 + 0.025*(v) *(d)1/3
|
Where d = depth of flow in feet (ft)
|
Where v = velocity of flow in feet per second (fps)
|
(b)
For conditions where the total energy content of the flow shall
be considered, such as bends, drops, abrupt changes in grade or areas,
convergence of flows, obstructions within the channel, and other conditions
that may produce a hydraulic jump, the minimum freeboard above the
flow surface of the major storm runoff shall be calculated using the
flowing equation:
Freeboard (in feet) = 0.5 + (v2/(2*g))*
|
Where g = gravitational constant 32.2 fps2
|
Where v = velocity of flow in feet per second (fps)
|
*Minimum freeboard under bridges shall be two feet.
|
O.
Detention and retention regional pond design.
(1)
Detention and retention regional pond design. The use of on-site
detention or retention is required for the purpose of limiting the
one-hundred-year storm runoff rates to historical levels. The type
of design for each facility is subject to approval by the County.
Ponding facilities shall adhere to the following:
(a)
Detention pond facilities shall be designed using a storage
outflow relationship for the facility and a flood hydrograph routing
procedure.
(b)
Off-site runoff entering the development may occur in the drainage
basin, and if this is the case, the analysis for the ponding facility
shall take the flows into account. Off-site runoff shall be analyzed
and may be routed around the ponding facility. However, entrance and
exit points of storm runoff shall not be altered.
(c)
For any ponding facility design, a soils report shall be included.
This report shall include, but shall not be limited to, soil boring
logs, water table elevations and soil classifications. Sufficient
and representative soil borings shall be required to characterize
the infiltration capacity of the soils located at the pond bottom.
(d)
An operation and maintenance plan acceptable to the County shall
be submitted for ponds that do not drain within 72 hours.
(e)
The banks of any pond shall be no steeper than a 4H:1V slope
unless an access ramp for vehicles is provided and measures are taken
to provide erosion protection of the banks. Any deviation from side
slope standards shall be justified by a geotechnical analysis and
shall be approved by the County Engineer.
(f)
All detention or retention facilities shall be provided with
a minimum twenty-foot access easement for operation and maintenance
of the facility. The minimum freeboard shall be one foot. The pond
shall be located a minimum of five feet from property lines and 10
feet from any structures.
(2)
The construction plans shall show the locations of all structures
and how the required volume will be controlled on site. Details on
walls and berms to control or direct runoff, asphalt and lot grades,
dimension and method of overflow of the storage area shall also be
depicted. The following are acceptable types of drainage structures:
(a)
Open ponds offer the maximum amount of storage for a given land
area and are recommended in areas having good percolation of water
into the soil. Open ponds shall have a minimum depth of 18 inches,
with the top of the pond located no closer than five feet to the property
lines and 10 feet to structures. An operation and maintenance plan
acceptable to the County shall be submitted for ponds that do not
drain within 72 hours. Pond bottoms shall not be located in poor percolation
rate layers such as clay soil types.
(b)
French drains are acceptable in areas with poor percolation
rates and shall only be used to provide increased percolation rates.
French drains shall have an open pond above the rock level with a
minimum depth of 12 inches.
(c)
Dry wells are generally used for drainage areas of one acre
or less and are designed exclusively to accept rooftop runoff from
residential and commercial buildings. They are similar to infiltration
trenches but smaller with inflow from pipe and commonly covered with
soil. The well shall be placed at a depth sufficient to contain the
required storage volume.
(3)
Detention pond best management practice.
(a)
Description. Best practice will combine detention ponds with
other site elements to reduce the area needed to fulfill detention
pond volume and storage requirements.
(b)
Method. Best practice will utilize active landscape features,
where applicable, to design areas required for retention/detention
basins, into multiple integrated features fulfilling total volume
requirements. Incorporate elements which work in combination with
required detention pond volume and storage. Integrate components of
existing site characteristics, topography, active landscape features,
building structures, and parking lot drainage. Best practices should
be coordinated with EDS and CDD staff.
[Amended 11-14-2017 by Ord. No. 294-2017]
P.
Drainage system operations and maintenance. Proper operations and
maintenance of storm drainage and flood control facilities, including
natural drainage systems such as arroyos, includes both cleaning and
minor repair to the facilities as well as completely rebuilding some
facilities that have, through weathering or lack of maintenance, been
rendered useless or present a threat to public safety. In order to
increase system efficiency, maintenance guidelines are outlined in
Table 6.25, Maintenance Guidelines, and shall be incorporated in the
drainage maintenance agreement (see sample form in Appendix A).[3] The drainage maintenance agreement shall be adopted by
operators of private drainage systems to establish maintenance procedures
of those systems. The agreement is to be signed and recorded as a
condition of final plat approval and shall be disclosed and acknowledged
by subsequent property owners.
Table 6.25 Maintenance Guidelines
| ||
---|---|---|
Facility
|
Maintenance, As Necessary
|
Inspection
|
Channels
|
May to October
|
Semiannual
|
Pump stations
|
May to October
|
Semiannual
|
Detention and retention facilities
|
May to October
|
After any major storm greater than 1 inch within a 24-hour period
|
Storm sewer systems
|
Annual
|
Biannual
|
Storm sewer inlets
|
After rainfall events or biweekly during rainy periods
|
Semiannual
|
Q.
As-built/record drawings. An as-built/record plan shall be submitted
after project completion to ensure that the construction complies
with the approved plans. The as-built/record plan shall be stamped
and certified by a licensed New Mexico professional engineer.
A.
Water and wastewater facilities.
(1)
Standards; review. All water and wastewater facilities shall meet the requirements of the American Water Works Association (AWWA), the New Mexico Standards for Public Works Construction (NMSPWC), the New Mexico Environment Department (NMED), the New Mexico Office of the State Engineer (OSE), and Doña Ana County's water and wastewater specifications; see Chapter 319, Wastewater Systems, and Chapter 324, Water Systems, where appropriate. If a proposed utility is to be owned and maintained by the County or any utility company, the design shall be reviewed and approved by the appropriate utility company.
B.
Water supply guidelines.
(1)
Water conservation measures.
(a)
The following water conservation measures are recommended for
housing units in all subdivisions:
(b)
All new construction shall conform to the requirements of the
International Building Code, International Residential Code, and Uniform
Plumbing Code, as adopted by Doña Ana County.
(c)
Low-water-use landscaping techniques applying the principles
of xeriscaping are highly recommended.
(2)
Quantification of annual water requirements. The following procedures
shall be used to quantify the maximum, annual water requirements for
all subdivisions:
(a)
The maximum annual water requirement for both indoor and outdoor
purposes, for each parcel in a residential subdivision, shall be 0.75
acre-feet per year, unless a detailed water demand analysis approved
by the State Engineer's Office justifies the use of a different figure.
The total annual water requirement for the subdivision in acre-feet
per year is computed by multiplying the number of parcels by 0.75.
(b)
The applicant may, at his/her option, prepare a detailed water
demand analysis using the step-by-step computational procedure presented
in the relevant State Engineer Technical Report.
(c)
A detailed water demand analysis shall be prepared for all nonresidential
subdivisions and all water uses not directly related to residential
uses within a mixed development subdivision. Annual water requirements
shall be estimated using the relevant State Engineer Technical Report.
(3)
Final plat approval requirements. In acting on the permit application,
the State Engineer shall determine whether the amount of water permitted
is sufficient in quantity to fulfill the maximum annual water requirements
of the subdivision, including water for indoor and outdoor domestic
uses.
(4)
Water conservation best management practice.
(a)
Description. Best practice will utilize passive water harvesting
to collect stormwater, which promotes water infiltration, stormwater
reduction, less complex erosion control and infrastructure systems,
and optimal landscaping. Utilizing harvested stormwater will provide
or offset landscape water needs.
(b)
Method. Best practice will include passive water harvesting
functions, which utilize gravity to direct the flow of stormwater
into active landscape features. Best practices should be designed
without additional tanks, piping, metering, pumps, or other infrastructure
associated with containment systems.
(c)
In certain configuration, additional infrastructure components
will be needed to route overflow water, convey water under roads or
parking lots, or for other purposes conducive to effective functioning
of the passive system. Best practices should be coordinated with EDS
and CD Department staff.
[Amended 11-14-2017 by Ord. No. 294-2017]
C.
Water quality; liquid and solid waste disposal.
(1)
Water quality documentation. For an applicant to document conformance
with the water quality requirements of these guidelines and the New
Mexico Subdivision Act, NMSA 1978, § 47-6-1 et seq., a water
quality documentation package shall accompany the preliminary plat
submission.
(a)
The water quality documentation package shall:
[1]
State the applicant's name and mailing address;
[2]
State the date the package was completed;
[3]
State the applicant's proposal for meeting the water quality
requirements of these guidelines;
[4]
Be accompanied by a copy of the applicant's disclosure statement
on water quality;
[5]
Be accompanied by the information listed in § 350-606C(1)(b), (c), or (d) of this section as applicable to the water supply proposal; and
[6]
Be accompanied by other relevant information as may be necessary
for the determination of compliance with the water quality requirements
of these guidelines.
(b)
If a new public water supply system (15 or more connections)
is proposed, the following information shall be submitted as part
of the water quality documentation package:
[1]
A water quality analysis of a representative water sample for
antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide,
fluoride, lead, mercury, nickel, nitrate, nitrite, selenium, thallium,
alkalinity, aluminum, calcium, chloride, color, copper, foaming agents,
hardness, iron, manganese, odor, pH, silver, sodium, sulfate, total
dissolved solids, turbidity, and zinc;
[2]
For areas where contamination of the proposed source water has
been documented, a water quality analysis of a representative water
sample for other water quality parameters may be required;
[3]
The location and description of the source of water sampled
for the water quality analysis;
[4]
An engineer's report and preliminary plans for the proposed
public water supply system; and
[5]
Maps identifying and showing the location of all identifiable
potential sources of contamination and the floodplain of all watercourses
and surface bodies of water within 1,000 feet of the proposed water
supply system source.
(c)
If a connection to an extension of an existing public water
supply system is proposed, the following information shall be submitted
as part of the water quality documentation package:
[1]
A water quality analysis of a representative water sample for
alkalinity, aluminum, calcium, chloride, color, copper, foaming agents,
hardness, iron, manganese, odor, pH, silver, sodium, sulfate, total
dissolved solids, turbidity, and zinc;
[2]
A statement of availability of water service signed by an official
of the existing public water supply system; and
[3]
An engineer's report and preliminary plans for the proposed
extensions to the existing water system.
(d)
If private water supply systems (individual wells, or cluster
wells serving fewer than 15 connections) are proposed, the following
information shall be submitted as part of the water quality documentation
package:
[1]
A water quality analysis of a representative water sample for
antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide,
fluoride, lead, mercury, nickel, nitrate, nitrite, selenium, thallium,
alkalinity, aluminum, calcium, chloride, color, copper, foaming agents,
hardness, iron, manganese, odor, pH, silver, sodium, sulfate, total
dissolved solids, turbidity, and zinc;
[2]
For areas where contamination of the proposed source water has
been documented, a water quality analysis of a representative water
sample for other water quality parameters may be required;
[3]
The location and description of the source of water sampled
for the water quality analysis;
[4]
Preliminary plans for the private water supply systems if the
system will serve more than one connection; and
[5]
Maps identifying and showing the location of all identifiable
potential sources of contamination and the floodplain of all watercourses
and surface bodies of water within the subdivision and within 500
feet of the proposed subdivision boundaries.
(e)
Documentation of approval for the construction or modification
of a public water supply system from the New Mexico Environment Department
will be required for final plat approval.
(2)
Liquid waste disposal documentation. For an applicant to document
conformance with the liquid waste disposal requirements of these guidelines
and the New Mexico Subdivision Act (see NMSA 1978, § 47-6-1
et seq.), a liquid waste disposal documentation package shall accompany
the preliminary plat submission.
(a)
The liquid waste disposal documentation package shall:
[1]
State the applicant's name and mailing address;
[2]
State the date the package was completed;
[3]
State the applicant's proposal for meeting the liquid waste
disposal requirements of these guidelines;
[4]
Be accompanied by a copy of the applicant's disclosure statement
on liquid waste disposal;
[5]
Be accompanied by the information required in § 350-606C(2)(b), (c), or (d) of this section as applicable to the applicant's liquid waste disposal proposal; and
[6]
Be accompanied by other relevant information required by the
State Environment Department as may be necessary to determine whether
there are sufficient liquid waste disposal facilities to fulfill the
requirements of the subdivision in conformity with state regulations
promulgated pursuant to the Environmental Improvement Act, NMSA 1978,
§ 74-1-1 et seq.; the Water Quality Act, NMSA 1978, § 74-6-1
et seq.; and the Solid Waste Act, NMSA 1978, § 74-9-1 et
seq.; and whether the applicant can fulfill the proposals contained
in his/her disclosure statement concerning water quality and concerning
liquid waste disposal facilities.
(b)
If the applicant proposes a new community liquid waste system,
the following information shall be submitted as part of the liquid
waste disposal documentation package:
[1]
An engineer's report and preliminary plans for the proposed
community liquid waste system;
[2]
Maps showing the location of all water supply sources and the
floodplain of all watercourses and surface bodies of water within
1,000 feet of the proposed liquid waste treatment and liquid waste
disposal site; and
[3]
Documentation of the filing of a notice of intent to discharge
with the New Mexico Environment Department in accordance with the
Water Quality Control Commission Regulations.
(c)
If the applicant proposes a liquid waste system, by connection
to and extension of an existing community liquid waste system, the
following information shall be submitted as part of the liquid waste
disposal documentation package:
(d)
If the applicant proposes a subdivision utilizing individual
liquid waste systems, the following information shall be submitted
as part of the liquid waste disposal documentation package:
[1]
Percolation rate for the soils present within the proposed subdivision,
and, if the general geologic characteristics of the area in which
the subdivision is located indicate that either the seasonal high
groundwater level or the surface of bedrock or other competent substrata
may be located within eight feet of the ground surface, a soils investigation
report (soil survey, soil borings to a minimum depth of eight feet,
soil test results and analysis of the soil survey, soil boring, and
soil tests) defining soil depth to bedrock, seasonal high water groundwater
table or other limiting soil layer. If a soils investigation is required,
soil borings shall be conducted within the property at a rate of one
boring per 10 acres or part thereof;
[2]
Maps showing the location of all water supply sources and the
floodplain of all watercourses and surface bodies of water within
the proposed subdivision and within 500 feet of the proposed subdivision
boundaries;
[3]
Preliminary plans for the individual liquid waste systems if
a system will serve more than one connection; and
[4]
Other relevant information required by the State Environment
Department as may be necessary for determination whether there are
sufficient liquid waste disposal facilities to fulfill the requirements
of the subdivision in conformity with state regulations promulgated
pursuant to the Environmental Improvement Act, NMSA 1978, § 74-1-1
et seq.; the Water Quality Act, NMSA 1978, § 74-6-1 et seq.;
and the Solid Waste Act, NMSA 1978, § 74-9-1 et seq.; and
whether the applicant can fulfill the proposals contained in the disclosure
statement concerning water quality and concerning liquid waste disposal
facilities.
(e)
Documentation of approval for the discharge from a community
liquid waste system from the New Mexico Environment Department will
be required for final plat approval.
(3)
Liquid waste disposal requirements. Conformance with the liquid
waste disposal requirements of this section is required for preliminary
plat approval.
(a)
Community liquid waste systems. Community liquid waste systems
shall be required for all subdivisions:
[1]
In which any lot created by the subdivision is less than 0.75
acre in size, unless detailed engineering studies and designs are
provided that meet the requirements for approval of a variance from
the Environment Department; or
[2]
Which create more than 100 lots, any of which is less than 1.5
acres in size.
[3]
A community liquid waste system shall be permitted, designed,
and constructed, by the time of first occupancy within the subdivision,
to comply with the Water Quality Control Commission regulations; and
be operated, maintained, and expanded as necessary to ensure that
the system will comply with the Water Quality Control Commission regulations.
[4]
The lot minimum sizes for individual liquid waste systems are
per Table 6.26, Lot Sizes for Individual Liquid Waste Systems, Minimum
Lot Size*.
(b)
Individual liquid waste systems. Individual liquid waste systems
shall be located, installed, operated, and maintained in a manner
which will not cause a hazard to public health or degrade any body
of water.
[1]
Individual liquid waste systems shall not be installed:
[a]
Where an existing community liquid waste system
has been designed and constructed for use within the subdivision;
[b]
In subdivisions or on lots with sizes less than
shown in Table 6.26, Lot Sizes for Individual Liquid Waste Systems
Minimum Lot Size*;
[c]
At less than the setback distances shown in Table
6.27, Setback Distances for Individual Liquid Waste Systems;
[d]
Consisting of privies (outhouses) or cesspools;
and
[e]
Consisting of holding tanks if an individual water
supply system is to be used.
[2]
The disclosure statement for the subdivision shall contain a
description of the means of liquid waste disposal for the subdivision.
[3]
Prior to certificate of occupancy approval for a residence or
business, the applicant for certificate of occupancy shall demonstrate
the installation of an individual liquid waste disposal system in
accordance with a permit approved by the Environment Department, or
connection to a community liquid waste system, if available.
Table 6.26 Lot Sizes for Individual Liquid Waste
Systems, Minimum Lot Size*
| ||||
---|---|---|---|---|
Community water system
|
0.75 acre(2)
|
0.75 acre(2)
|
1.0 acre
|
(3)
|
Individual water supply
|
0.75 acre(2)
|
1.0 acre
|
1.25 acre
|
(3)
|
Percolation rate (minutes per inch)
|
5 to 15
|
16 to 30
|
31 to 60
|
Less than 5 or more than 60
|
Soil depth(4)
|
More than 7 feet
|
More than 7 feet
|
More than 7 feet
|
Less than 7 feet
|
Slope (percent)
|
Less than 8%
|
Less than 8%
|
8% to 25%
|
More than 25%
|
Design flow
|
375 gallons/day(5)
|
(5)
|
(5)
|
(5)
|
Notes:
| |
(1)
|
In the use of this table, the minimum allowable lot
size is to be based upon the largest minimum lot size determined by
any one of the limiting characteristics listed in the table.
|
(2)
|
Lots smaller than 0.75 acre in size shall be provided
with a) service from a community liquid waste system, or b) detailed
engineering studies and designs meeting the requirements for variance
approval from the Environment Department.
|
(3)
|
Any lots with any of these characteristics shall be
provided with individual liquid waste disposal systems based upon
detailed engineering studies and designs approved by the Environment
Department or be provided with alternative means of liquid waste disposal
|
(4)
|
Soil depth is measured from the ground surface to
any one of the following: a) seasonal high groundwater level; b) bedrock;
or c) the upper surface of any limiting soil layer.
|
(5)
|
The minimum lot size required for individual liquid
waste systems based upon design flow (375 gallons per day minimum)
shall be computed as follows: Lot Size (acres) = Total Design Flow
(gallons per day)/500, except where detailed engineering studies and
designs have been approved for a variance from the Environment Department.
|
*
|
Pending NMED review and approval
|
Table 6.27 Setback Distances for Individual Liquid Waste
Systems
| ||
---|---|---|
|
Required Minimum Setback Distance
(feet)
| |
Object
|
Treatment Unit
|
Disposal System
|
Lot line
|
5
|
5
|
Individual water supply system source
|
50
|
100
|
Public water supply system source
|
100
|
200
|
Edge of watercourses, except canals and arroyos
|
50
|
100
|
Edge of unlined canals and arroyos
|
15 + depth of channel
|
25 + depth of channel
|
Edge of lined canals
|
10 + depth of channel
|
10 + depth of channel
|
Public lakes
|
50(a)
|
100(a)
|
Notes:
| |
(a)
|
Setback distance to artificially controlled lakes and reservoirs
is measured from the closest projected shoreline at the maximum controlled
water level.
|
(b)
|
All components of individual liquid waste systems shall be constructed
so as to not be affected by floodplains.
|
(4)
Solid waste disposal documentation. For an applicant to document
conformance with the solid waste disposal requirements of these guidelines
and the New Mexico Subdivision Act, NMSA 1978, § 47-6-1
et seq. A solid waste disposal documentation package shall accompany
the preliminary plat submission.
(a)
A solid waste documentation package shall:
[1]
State the applicant's name and mailing address;
[2]
State the date the package was completed;
[3]
State the applicant's proposal for meeting the solid waste disposal
requirements of these guidelines;
[4]
Be accompanied by a copy of the applicant's disclosure statement
on solid waste disposal;
[5]
Be accompanied by the information required in § 350-606C(4)(b) of this section as applicable to the applicant's solid waste collection and disposal proposal; and
[6]
Be accompanied by other relevant information required by the
State Environment Department as may be necessary to determine whether
there are sufficient solid waste disposal facilities to fulfill the
requirements of the subdivision in conformity with state regulations
promulgated pursuant to the Environmental Improvement Act, NMSA § 74-1-1
et seq.; the Water Quality Act, NMSA 1978, § 74-6-1 et seq.;
and the Solid Waste Act, NMSA 1978, § 74-9-1 et seq. and
whether the applicant can fulfill the proposals contained in the disclosure
statement concerning water quality and concerning liquid waste disposal
facilities.
(b)
The disclosure statement for the subdivision shall contain a
description of the means of solid waste disposal for the subdivision,
including the following information:
[1]
For subdivisions in which solid waste collection service is
available, the disclosure statement shall include a statement of availability
of solid waste collection and disposal service signed by an official
of the solid waste collection service.
A.
Access roads; water supplies and fire hydrants; plans.
(1)
Access roads to all developments shall meet the provisions of this chapter, and shall be improved and maintained in accordance with Chapter 195, Fire Prevention.
(2)
Water supplies and fire hydrants shall be located, positioned
and constructed in accordance with the current Doña Ana County
adopted fire code. Such equipment shall be installed and maintained
to meet fire flow, be compatible with Fire Department equipment and
shall be approved by the County Fire Chief's office.
(3)
The fire protection plans shall be submitted along with the
preliminary plat and shall be stamped and certified by a licensed
New Mexico professional engineer, indicating that the fire plans meet
the specifications of the Doña Ana County adopted fire code.
A letter from the local water district stating that the water supply
and fire hydrants shall be maintained by that local water district
shall be submitted with the plans.