A.
Appropriate sections from Chapter 324, Subdivision and Land Development, of the Code of the Municipality of Monroeville, and other applicable local ordinances shall be followed in preparing the SWM site plans.
B.
The Municipality shall not approve any SWM site plan that is deficient
in meeting the requirements of this chapter. At its sole discretion
and in accordance with this article, when an SWM site plan is found
to be deficient, the Municipality may either disapprove the submission
and require a resubmission or, in the case of minor deficiencies,
the Municipality may accept submission of modifications.
C.
The following items shall be included in the SWM site plan:
(1)
Provisions for permanent access or maintenance easements for all
physical SWM BMPs, such as ponds and infiltration structures, as necessary
to implement the operation and maintenance (O&M) plan.
(2)
The following signature block for the Municipality:
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"[Municipal official or designated plan reviewer (§ 319-28)], on this date (signature date), has reviewed and hereby certifies that the SWM site plan meets all design standards and criteria of the Municipal Ordinance No. 2541,[1] except where waivers have been granted as noted on the
plan. The review is based on a survey and plan prepared by others
and assumes that all information is correct and valid as submitted."
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[1]
Editor's Note: This is a reference to a prior version of this
ordinance.
(3)
The overall stormwater management concept for the project.
(4)
For all regulated activities not eligible for exemptions pursuant to § 319-6 of this chapter, the applicant shall submit a stormwater management plan and report prepared and sealed by a professional engineer or landscape architect licensed in the Commonwealth of Pennsylvania, which shall contain, but not be limited to, the following. Final copies of all plans, specifications and reports shall also be submitted to the Municipality in Adobe PDF format.
(a)
A location map of the watershed within which the project is
proposed (a United States Geological Survey quadrangle map is sufficient)
with existing and proposed development areas shown.
(b)
Maps and drawings, in accordance with Chapter 324, Subdivision and Land Development, showing all existing natural and constructed drainage facilities affecting the subject property.
(c)
Hydrologic (watershed) and water feature boundaries, including
all areas flowing to the proposed project, existing streams (including
first-order and intermittent streams), springs, lakes, ponds, or other
bodies of water within the project area.
(d)
Existing and proposed topographical information with elevations
to verify the location of all ridges, streams, etc. Two-foot contour
intervals are required within the project's boundaries and for proposed
off-site improvements; for slopes greater than 15%, five-foot contours
are acceptable.
(f)
Soils data with hydrologic soil group, estimated permeability
in inches per hour, and location and results of all soil tests and
borings (if needed).
(g)
One-hundred-year flood elevations for any floodplains on or
within 100 feet of the property.
(h)
Existing and proposed ground cover and land use. The total area
and percent impervious cover shall be noted.
(i)
A wetland delineation report for the project site with a location
map identifying wetland areas if necessary.
(j)
A plan of the proposed stormwater drainage system, including
runoff calculations, stormwater management practices to be applied
both during and after development, and the expected project time schedule.
(k)
The design computations for all proposed stormwater drainage
systems, including storm sewer pipes, inlets, runoff control measures
and culverts, drainage channels, and other features, facilities, and
stormwater management practices.
(l)
A grading plan, including all areas of disturbance of the subject
activity. The total area of disturbance shall be noted in square feet
and acres. Topographic contours showing the existing and proposed
final contours at an interval of two feet; in areas having slope of
greater than 15%, a five-foot contour interval may be used.
(m)
A plan of the erosion and sedimentation procedures to be utilized,
as prepared for and submitted to the approval authority.
(n)
The effect of runoff volumes and peak flows on adjacent properties
and on any other stormwater collection system that may receive runoff
from the project site and specifics of how erosion and flooding impacts
to adjacent properties will be avoided or otherwise mitigated.
(o)
An operation and maintenance plan consistent with the requirements of Article V of this chapter. The plan should clearly explain how the proposed facilities operate and the junctions they serve.
(p)
The name of the development, the name and address of the property
owner and applicant, and the name and address of the individual or
firm preparing the plan.
(q)
A North arrow, submission date, graphic scale and revision dates,
as applicable, shall be included on each page of all plans submitted.
(r)
Complete delineation of the flow paths used for calculating
the time of concentration for the predeveloped and post-developed
conditions.
(s)
Construction details sufficient to completely express the intended
stormwater design components consistent with this chapter.
(t)
A listing of all permits required for the site, providing the
status of the permit application(s) and approval(s).
(u)
For any sites with existing stormwater management facilities
or BMPs, the nature and condition of such facilities must be discussed
in the stormwater management plan narrative. If the existing facilities
are proposed to remain intact and function as all or part of the facilities
required for the project, the following information must be included
in the stormwater management plan:
[1]
Inspections and/or certifications that the existing facilities
are sized and capable of operating as required, including:
[a]
Surveys of all pertinent elevations associated
with the facility, including but not limited to inverts or channel
bottoms, outlet controls, embankments, and receiving streams or structures;
[b]
Internal conditions of all underground pipes and
structures, including the use of photographs or video for documentation;
[c]
Design calculations from the facilities' original
construction, if available;
[d]
Operation and maintenance records, if available.
[2]
Plans and descriptions of any alterations proposed to the facilities.
[3]
Runoff and design calculations.
(v)
A post-development drainage map delineating the area tributary
to each receiving feature or facility (inlet, BMP, swale, roadway,
etc.).
(w)
Subsurface facilities hydraulically connected to a PennDOT drainage
facility, and/or new or modified subsurface stormwater facilities
in a PennDOT right-of-way draining the highway and/or adjacent properties
shall be identified. The long-term operation and maintenance of such
facilities shall be in conformance with the current requirements of
PennDOT's Highway Occupancy Permit program.
(x)
A justification, acceptable to the designated plan reviewer,
must be included in the SWM site plan if BMPs other than green infrastructure
methods and LID practices are proposed to achieve the volume, rate,
and water quality controls under this chapter.
A.
Purpose. On large previously developed[1] the Municipality may permit or require a master stormwater
management mitigation plan (MSMMP) to be developed for the entire
site or project which will be implemented incrementally by a series
of more detailed stormwater management plans and designs developed
in accordance with the MSMMP.
[1]
Editor's Note: So in original.
B.
Goals. The intent of the MSMMP is to guide the development or redevelopment
of a large project or site, including the retrofitting of stormwater
management, by managing the site as a whole instead of as individually
distinct pieces. The overriding goals of the MSMMP are:
C.
Criteria.
(1)
In order to qualify for an MSMMP, the site or project must include more than one principal structure as defined by Chapter 359, Zoning, and exceed 10 acres at the date of application.
(2)
Because sites and projects can cross property lines, the Municipal
Engineer will determine what area the site or project encompasses.
(3)
The Municipal Engineer may require or permit projects outside of
these criteria to employ an MSMMP or may deny use of an MSMMP to projects
that meet the criteria based on the Municipal Engineer's professional
judgment.
D.
Master stormwater management mitigation plan requirements.
(1)
The MSMMP must be prepared and sealed by a professional engineer
or landscape architect licensed in the Commonwealth of Pennsylvania.
(2)
The predevelopment assumptions for the MSMMP will be those which
exist at the date of the last approved stormwater management plan
for the site; should one exist otherwise, it will be that which exists
at the date of application. Said predevelopment assumptions shall
remain unchanged for the MSMMP throughout the life of the MSMMP.
(3)
The Municipal Engineer must approve the geographical scope of the
plan due to the fact that projects or developments, whether existing
or proposed, can spread across multiple properties or can encompass
relatively small portions of a large property.
(4)
The MSMMP shall contain the following:
(a)
The name of the development, the name and address of the property
owner and applicant, and the name and address of the individual or
firm preparing the plan.
(b)
A North arrow, submission date, graphic scale and revision dates,
as applicable, shall be included on each page of all plans submitted.
(c)
A location map of the watershed within which the project is
proposed (a United States Geological Survey quadrangle map is sufficient)
with the project area shown.
(d)
Maps and drawings, in accordance with Chapter 324, Subdivision and Land Development, showing all existing natural and constructed drainage and stormwater management facilities affecting the subject property.
(e)
Hydrologic (watershed) and water feature boundaries, including
all areas flowing to the project, existing streams (including first-order
and intermittent streams), springs, lakes, ponds, or other bodies
of water within the project area.
(f)
Existing topographical information with elevations to verify
the location of all ridges, streams, etc. Two-foot contour intervals
are required within the project's boundaries and for proposed off-site
improvements; for slopes greater than 15%, five-foot contours are
acceptable.
(h)
Soils data with hydrologic soil group, estimated permeability
in inches per hour, and location and results of all soil tests and
borings (if needed).
(i)
One-hundred-year flood elevations for any floodplains on or
within 100 feet of the property.
(j)
Existing ground cover and land use. The total area and percent
impervious cover shall be noted.
(k)
A wetland delineation report for the project site with a location
map identifying wetland areas if necessary.
(l)
Design calculations and maps used to calculate the predevelopment peak runoff rates from the site in accordance with Article IV of this chapter.
(m)
Design calculations and maps used to calculate the two-year, twenty-four-hour design storm runoff volume to be managed in accordance with Article IV of this chapter.
(n)
Identification of any areas on-site currently negatively impacted
by stormwater runoff (such as erosion gullies below outfalls, displaced
erosion protection, areas of frequent flooding or ponding, malfunctioning
detention facilities or BMPs, etc.) as well as a plan to remedy those
issues.
(o)
Complete delineation of the flow paths used for calculating
the time of concentration for the predeveloped conditions.
(p)
For any sites with existing stormwater management facilities
or BMPs, the nature and condition of such facilities must be discussed
in the MSMMP narrative. If the existing facilities arc proposed to
remain intact and function as all or part of the facilities required
for the project, the following information must be included in the
MSMMP:
[1]
Inspections and/or certifications that the existing facilities
are sized and capable of operating as required, including:
[a]
Surveys of all pertinent elevations associated
with the facility, including but not limited to inverts or channel
bottoms, outlet controls, embankments, and receiving streams or structures;
[b]
Internal conditions of all underground pipes and
structures, including the use of photographs or video for documentation;
[c]
Design calculations from the facilities' original
construction, if available;
[d]
Operation and maintenance records, if available.
[2]
Plans and descriptions of any alterations proposed to the facilities.
[3]
Runoff and design calculations.
(q)
Phasing. The maximum number of phases the MSMMP can encompass
shall be determined by calculating the greater of the following criteria
(based upon the existing conditions of the parcel at the time of initial
MSMMP application) not to exceed eight phases nor be less than two
phases:
(5)
Master stormwater management mitigation plan implementation.
(a)
The MSMMP shall be designed to reduce the site peak runoff rates
to the prescribed predevelopment rates and mitigate and treat the
two-year, twenty-four-hour runoff volume difference via a prescribed
number of phases as previously defined with each phase making either
equal progress toward those goals or by "front-loading" the phases
if desired so that progress is maximized in the first phase and diminishes
through later phases.
(b)
Each phase shall make the required progress towards meeting the overall site goals listed in item § 319-18D(5)(a) while also accounting for its own individual impacts.
(c)
Phases shall be triggered by initiation of a regulated activity
or elapsing of five years since the commencement of the prior phased.
(d)
Each phase shall develop a stormwater management plan in accordance with § 319-17 that must show clearly how the phase will mitigate the impacts of the changes proposed in the phase as well as how the phase will meet its incremental progress goals for the overall site in accordance with the MSMMP.
(6)
Master stormwater management mitigation plan lifecycle.
(a)
The MSMMP shall be in full force until its prescribed number
of phases have been completed.
(b)
The MSMMP shall remain in full force regardless of change in
ownership of the involved property (properties) or facilities. The
landowner shall record in the office of the Allegheny County Department
of Real Estate a declaration in a form satisfactory to the Municipal
Solicitor, setting forth the responsibilities of the landowner to
complete the MSMMP. The declaration shall be perfected to run with
the land and be binding upon the landowner and any successors in interest
until the MSMMP's completion.
(c)
Should the Municipality's stormwater management regulations
or other applicable regulations change while the MSMMP is in effect,
the MSMMP must be revised so that only the remaining phases must comply
with the changes.
