The town has prepared these drainage regulations and design standards in order to expedite the development process and maintain the quality of development, as well as the protection of life and property, within the town’s jurisdiction. It is intended that this chapter clearly display the town’s expectations from applicants and applicants’ engineers and present a process that is consistent throughout the town. In so doing, applicants realize an expedited process which ultimately makes development less expensive, less time consuming, and less confining, without sacrificing quality development or the health, welfare and safety of the citizens of Taos.
(Ordinance 97-5 adopted 1997)
A. 
The town will continue to serve a role in development with regard to education of the process, filing of submitted documents, and review of the technical information submitted. The town will make no acceptance, written or implied, of the validity of an individual drainage plan. In reviewing and commenting upon the drainage plans submitted, the town only accepts these documents for filing purposes. The town will continue to review the technical information submitted; however, the applicant and the applicant’s engineer are solely responsible for the integrity of the plan submitted and the conformance to the regulations in place at the time. Any submittal made by an applicant or applicant’s engineer which does not fully comply with the conditions set forth in these regulations will be the full responsibility and liability of the applicant, even if the town accepts the plan for filing without comment.
B. 
If a drainage plan is submitted and omits or ignores any part of these regulations, and the town accepts the plan for filing without commenting on these omissions, this will not be construed as the town’s approval of a waiver of the conditions. All conditions stated in these drainage regulations will remain in effect. Any portion of these drainage regulations which are not addressed in an individual drainage submittal will remain the full responsibility and liability of the applicant. The only waiver which will be granted shall be those given in writing by an authorized representative of the town.
(Ordinance 97-5 adopted 1997)
A. 
The design, construction and maintenance of all drainage control, flood control and erosion control facilities within the town and its extraterritorial areas shall be performed in accordance with procedures, criteria and standards in accordance with the policies established in this chapter.
B. 
The storm drainage ordinance shall be the administrative manual providing details and supporting information to the land use development code. (See title 16 of this code.)
C. 
All construction activities within the jurisdiction of the town shall conform to the requirements of the code administrator and this chapter.
1. 
Individual residential development.
Complete the residential land use application preliminary information form, which can be found in the “forms” section of the ordinance codified in this chapter and on file in the town clerk’s office. Submit the completed form to the planning department along with a “site plan”, as defined herein, which displays all applicable information from the residential land use application preliminary information form. The planning department will review this information and inform the applicant if a drainage plan will be required. The code administrator reserves the right to enact the drainage policies on any site, or exclude any site from these policies.
2. 
Commercial development.
A drainage plan, including all items on the checklist, will be required for all commercial development.
3. 
Multi-lot or subdivision development.
A drainage plan, including all items on the checklist, will be required for all multi-lot or subdivision development.
Note: Any proposed development which does not fall into one of the above listed categories will follow the guidelines listed for individual residential development.
In addition, any construction (regardless of size) within one hundred fifty feet (150') from the centerline of an established arroyo shall require a drainage plan prepared by a professional engineer, unless otherwise approved by the code administrator.
D. 
Grading, cut, fill or importation of material in excess of five hundred (500) cubic yards or grading of any area of one acre or more shall conform to drainage control, flood control and erosion control policies and to standards, criteria and procedures established by this chapter.
E. 
Requests for the platting of land for the purpose of subdivision or development shall be accompanied by appropriate drainage control, flood control and erosion control information.
F. 
A development review fee in the amount set forth in the fee schedule in appendix A of this code shall be paid at the time of submittal to the town which assists in the payment of expenses accrued due to review of the proposed development. All commercial and multi-lot developments, or developments where special complex circumstances may warrant, shall pay the development review fee. If required, additional fees may be transferred to the applicant, on a time and material basis only, for more complex reviews and/or site visits.
(Ordinance 97-5, sec. 1-1, adopted 1997; Ordinance adopting 2023 Code)
As used in this chapter:
Design storm.
A storm which deposits a stated amount of precipitation within a stated period of time over a defined area, and which is used in calculating storm runoff and in designing drainage control, flood control, and erosion control measures.
Detention pond.
A pond designed for the volume of the 100-year 24-hour design storm, and which has outfall piping to drain the pond in less than twenty-four (24) hours at a rate not to exceed the historical discharge rate.
Development site.
The site of proposed development.
Drainage easement.
Public right-of-way dedicated to the town for the purpose of handling storm drainage.
Drainage plan.
A detailed plan, prepared and stamped by a registered professional engineer, in graphical format with a detailed grading plan addressing on-site and off-site drainage control, flood control, and erosion control issues for development sites.
Energy grade line (EGL).
A calculated value used to define the limits of a drainage easement established by the channel analysis of the defined watercourse.
Erosion control.
Treatment measures for the prevention of damages due to soil movement and deposition during a rainstorm.
Floodway.
The channel of a river, arroyo, or other watercourse and adjacent land areas that must be reserved in order to safely discharge the 100-year design storm runoff.
HEC-2 or HECRAS.
Standard computer programs which employ one-dimensional, step-back water calculations to estimate energy losses along a channel.
Peak discharge.
The maximum rate of the storm water runoff resulting from the design storm.
Project design swale (also referred to as swale, drainage ditch, berm, barrow ditch, or bar ditch).
A constructed swale used to convey storm water runoff to ponds, or to return runoff to historical drainage paths.
Retention pond.
A pond designed for the volume of the 100-year 24-hour design storm without any release.
Site plan.
A plan, drawn to scale, showing uses and structures proposed for a parcel of land as required by the code. It includes, as required by the code, lot lines, streets, building sites, reserved open space, buildings, major landscape features, both natural and artificial, and the locations of proposed utility lines.
Watercourse.
Any river, creek, arroyo, canyon, draw, wash, or any other channel having a definite bank and bed with visible evidence of the occasional flow of water.
(Ordinance 97-5, sec. 1-2, adopted 1997)
A. 
Intent and purpose.
It is the purpose of the terrain management regulations to: ensure sound and orderly development of the natural terrain; protect life and property from the dangers of flooding and the hazard of improper cuts and fills; minimize erosion and destruction of the natural landscape; protect the scenic character of Taos from the visual blight of indiscriminate cuts and fills and devegetation resulting from extensive grading; and otherwise protect public health, safety and welfare.
B. 
General provisions.
The terrain management regulations listed in this section are applicable to and binding upon development in the town and its extraterritorial planning and platting jurisdiction.
C. 
Natural topography performance standards.
1. 
General provisions.
a. 
Each lot shall have a building site of not less than two thousand (2,000) square feet and said building site shall have a natural slope less than twenty percent (20%) and which can be developed in accordance with the terrain management performance standards. Buildings shall be constructed on the building site.
b. 
Natural topography submittals for all commercial and multi-lot sites shall be certified by a New Mexico licensed land surveyor and shall specify date and method of surveys and compliance with natural map accuracy standards, unless otherwise approved by the code administrator.
2. 
A natural topography plan shall be submitted indicating the following:
a. 
All areas with a natural slope twenty percent (20%) or greater shall be clearly marked by shade, or tone, or color at the same scale required for preliminary subdivision plat.
b. 
Ground elevations on the tract shall conform to the United States Geological Survey datum and shall be plotted according to the following method:
(1) 
For lands that slope more than approximately twenty percent (20%), elevation contours shall be drawn at not more than five foot (5') intervals.
(2) 
For lands that slope less than approximately twenty percent (20%), elevation contours shall be drawn at not more than two foot (2') intervals.
(Ordinance 97-5, sec. 1-3, adopted 1997)
A. 
General provisions.
1. 
The basis of drainage shall be the 100-year 24-hour frequency rainstorm.
2. 
Grading and drainage plans shall have the following engineer’s certification:
I hereby certify that I am a Registered Professional Engineer in the State of New Mexico. To the best of my knowledge, information, and belief, this grading and drainage plan was prepared in general conformance with the Storm Drainage Ordinance 97-05, and is in compliance with applicable laws, codes, and ordinances. I personally inspected the site, and the topography shown on this plan is representative of the site.
This statement shall be placed on the first page of the grading and drainage plan along with the engineer’s signed and dated seal.
3. 
The peak discharge of storm water resulting from the development shall not exceed the peak discharge calculated prior to the development. All developed runoff shall be detained on the site so to not create adverse downstream conditions (increase of peak rate of discharge and/or volume).
4. 
The design, construction and maintenance of dams, levees, and diversions that fall within the jurisdiction of the state engineer of the State of New Mexico shall meet or exceed standards established by the state engineer.
5. 
Provisions for storm drainage shall be designed to safely retain or detain storm water or adequately carry and discharge accumulated runoff into drainage channels, storm sewers or other natural watercourses. Storm drainage facilities shall have sufficient carrying capacity to accept runoff from the development in addition to that originating upstream.
6. 
Detention ponds shall be designed to detain the volume generated from the site for a 100-year 24-hour design storm. Detention facilities may be used to include retention capacity for a portion of the pond volume. Detention ponds shall be designed and constructed to empty in twenty-four (24) hours or less.
7. 
Retention ponds shall be designed to retain the volume generated from the site for the 100-year 24-hour design storm.
8. 
All detention and retention facilities shall have a designated overflow spillway. The overflow spillway shall be capable of discharging the runoff entering the ponding facility for the 100-year 24-hour design storm.
9. 
All detention and retention facilities shall be constructed on private property. Any impact to town property and/or town facilities will require consideration and approval of town council.
10. 
All detention and retention facilities shall have a private deed restriction and/or public dedication easement dedicated to the town unless otherwise authorized by the code administrator.
11. 
Where considered necessary by the code administrator, the applicant shall be required to design and construct berm ditches along the top of cut slopes in order to intercept the tributary drainage above the cut slope. The design for these berm ditches shall be submitted with the final plat.
12. 
Existing watercourses shall not be disturbed. Any proposed excavation, fill, or channel improvements shall be reviewed and approved by the code administrator and/or town council.
13. 
All floodways shall be dedicated as drainage easements or drainage right-of-way.
14. 
On any application for land subdivision, the code administrator or planning commission may require the submittal of detailed hydrologic data indicating the water surface elevations for a 100-year flood, to be shown for sections of the drainage channel at intervals of no greater than one hundred feet (100').
15. 
All drainage plans and reports shall be prepared by an actively registered professional engineer in the State of New Mexico and approved by the code administrator. The approval of the code administrator (or any town employee, agent, commission or council, elected of appointed official, member of a commission, officer or retained professional) notwithstanding, the applicant, his/her/its heirs, assigns, grantees or successors in interest shall have no claim or cause of action against the code administrator (or any town employee, agent, commission or council, elected or appointed official, member of a commission, officer or retained professional) because of the granting of any permit. In addition, the applicant, his/her/its heirs, assigns, grantees or successors in interest shall save and hold harmless the town, its employees, agents, commission or councils, elected or appointed officials, members of commissions, officers or retained professionals from any and all claims, causes of actions, lawsuits, claims in arbitration, judgments, arbitration awards, and any other costs, expenses or damages, including, but not limited to, the town’s attorney fees and legal expenses, arising out of the granting of any permit.
16. 
The Soil Conservation Service’s method for determining rainfall depths shall be used to base all drainage design for the site. The quantities for the runoff shall be measured in volume V (cf) and discharge Q (cfs). These quantities shall be determined for the development site for existing and proposed conditions.
17. 
A surveyed public drainage easement shall be required for any watercourse traversing the site with ten (10) cfs or more of public waters or twenty (20) cfs of private waters. An HEC-2 or HEC-RAS analysis of the watercourse shall be submitted with the grading and drainage plan. The watercourse analyzed shall have no less than five (5) cross-sections which represent the characteristics of the channel. The energy grade line shall be plotted along with the drainage easement on the plan to verify the easement limits.
18. 
The maintenance of drainage facilities which serve private property is the responsibility of the developer and/or owner.
19. 
All commercial development and subdivisions shall submit as-constructed grading and drainage plans prior to final inspection. The code administrator may request as-constructed grading and drainage plans for any development within the town’s planning and platting jurisdiction.
20. 
Drainage requirements will be waived where a drainage report was previously approved prior to this chapter. Drainage requirements for all existing development will be waived until addition or alteration of the development is proposed.
21. 
It is the responsibility of the owner to coordinate all applicable development with NMED.
B. 
Use of streets for drainage and flood control purposes.
1. 
Channel crossing structures shall be provided on all arterial and collector streets to safely pass the 100-year design storm runoff from major arroyos assuming a fully developed watershed.
2. 
The surface streets may only be used for transport of runoff if designed in accordance with a storm drainage system, to the extent such use does not interfere with the safe transportation of people and vehicles. A minimum of twelve feet (12') of roadway shall be above the surface water elevation for the 100-year design storm for each direction of traffic. It is understood that the town has storm drainage facilities in certain areas. However, if discharge to town facilities is considered, the allowed use and required fee will be determined by the code administrator and/or town council prior to construction of the proposed improvements.
3. 
The 100-year design storm runoff shall not exceed a depth of 0.7 foot at any point within the street right-of-way, or 0.2 foot above the top of curb, in the street nor enter private property from a street, except in recorded drainage or flood control easements or right-of-way (or historic channels and watercourses where easements or right-of-way cannot be obtained).
4. 
The discharge of nuisance waters to public streets shall not be allowed. Streets shall be protected from damages to the pavement surface and from the safety hazards created by surface flow of nuisance waters across them.
5. 
All developed sites within the town’s jurisdiction shall be served by at least one access that shall be an all-weather facility designed for the 100-year frequency storm.
(Ordinance 97-5, sec. 1-4, adopted 1997)
A. 
General provisions.
A grading plan shall be submitted to the code administrator for approval.
1. 
All proposed grading shall be indicated on the grading plan by showing existing and proposed contours.
2. 
Grading operations shall conform to the grading plan. The developer shall provide a record survey after the completion of construction to verify compliance with the approved grading plan.
3. 
Cut or fill slopes for roads shall not exceed fifteen feet (15') in height.
4. 
Cut slopes for building sites shall not exceed fifteen feet (15') in height, unless a structural alternative acceptable to the code administrator is provided; but in no case shall the height of the cut exceed the height of the building.
5. 
The horizontal measurement for an exposed, unstabilized surface of the cut slope shall be graded not to exceed two to one (2:1) slopes, unless a structural alternative acceptable to the code administrator is provided, or unless it can be demonstrated by the grading plan that existing soils will naturally accommodate a steeper slope.
6. 
The horizontal measurement for an exposed, unstabilized surface of a fill slope shall be graded not to exceed three to one (3:1) slopes, unless a structural alternative acceptable to the code administrator is provided.
7. 
A soils engineering report as defined herein shall be provided for all subdivisions.
8. 
Soils described as having severe limitations for their intended use shall be clearly delineated on the grading plan.
B. 
Grading plan.
1. 
Cut or fill slopes shall be clearly shown on the grading plan and differentiated by shading, tone, color or line weight.
2. 
The grading plan shall show the ratio of horizontal to vertical measurement for cut and fill slopes.
3. 
The grading plan shall show existing and final contours to be achieved by the grading.
4. 
Areas of severe soils for the intended use shall be clearly shown on the grading plan.
(Ordinance 97-5, sec. 1-5, adopted 1997)
A. 
General provisions.
1. 
The faces of cut and fill slopes, or graded areas which are shown on the grading plan as subject to erosion, shall be prepared and maintained to control against erosion. The protection for cut and fill slopes and graded areas shall be constructed according to a time schedule approved by the code administrator.
2. 
Where structures are proposed as an erosion control method and a choice of alternative materials exists, the preference shall be given to the more natural material which shall be approved by the code administrator.
3. 
Where vegetation is proposed as an erosion control method for cleared or graded land, the new vegetation shall be maintained until established to adequately prevent erosion of cut slopes, fill slopes, or graded areas.
4. 
The applicant or his agent shall notify the code administrator when the erosion control structures are ready for final inspection. Final approval shall be granted by the code administrator when the erosion control structures have been completed in accordance with the approved erosion control plan.
5. 
The code administrator may inspect graded areas where vegetation is proposed as an erosion control measure to verify that such revegetation conforms to the submitted erosion control plan.
6. 
Where drought resistant grasses are utilized for erosion control, written specifications shall be submitted to the code administrator indicating the type of grass, the preparation of the seed bed, and the maintenance schedule.
B. 
Erosion control plan.
An erosion control plan shall be submitted indicating the following:
1. 
Detailed plans showing the location of all erosion control structures, and a time schedule for installation of said erosion control structures;
2. 
Location, type and amount of plant materials to be used for erosion control, and the month and year that all vegetation proposed for erosion control will be planted.
(Ordinance 97-5, sec. 1-6, adopted 1997)
A. 
A detailed grading and drainage plan shall be submitted to the town meeting the policies and criteria outlined in the land use development code, title 16 of this code. The this [sic] provides standards for development within the town’s jurisdiction.
B. 
It is recommended that the developer schedule a predesign meeting with the code administrator prior to application submittal.
C. 
The following items shall appear on grading and drainage plan. More information may be required depending on the site and proposed development. These basic items do not guarantee approval of the submitted grading and drainage plan. There may be additional issues to address prior to approval for each different plan:
1. 
Town application (provided in “forms” section of the ordinance codified in this chapter and on file in the town clerk’s office) and application fee, if applicable;
2. 
Engineer’s seal, signed and dated;
3. 
Surveyor seal, signed and dated, if applicable;
4. 
Engineer’s certification;
5. 
Floodway map, showing proximity to the established floodplain if within one thousand feet (1,000') of the development site;
6. 
Off-site topography map of upstream basins contributing flows to the site, one inch equals five hundred feet (1" = 500') or better;
7. 
Vicinity map;
8. 
Legal description, boundary survey, and address of the site;
9. 
North arrow;
10. 
Scale;
11. 
Fencing statement: states if fencing is/is not proposed, and how it impacts drainage through the site;
12. 
Location of well and septic system, if applicable;
13. 
Lot setback requirements per title 16 of this code;
14. 
Site access per title 16 of this code;
15. 
Utility easements;
16. 
Drainage easements: HEC-2 analysis of five (5) or more cross-sections at no more than fifty foot (50') intervals. The limits of the easement will be established by the energy grade line (EGL). The cross-sections, EGL, and limits of the easement must be plotted on the plan;
17. 
Building layout: finish floor elevations for all buildings;
18. 
Distinguish between existing and proposed development;
19. 
Distinguish between existing and proposed contours at no more than two foot (2') intervals;
20. 
Distinguish between existing and proposed hydraulic structures;
21. 
Hydrologic analysis:
a. 
Precipitation data: SCS method as shown with example in the ordinance codified in this chapter and on file in the town clerk’s office;
b. 
On-site land treatments (existing and proposed) see the ordinance codified in this chapter and on file in the town clerk’s office and refer to example in “forms” section;
c. 
Off-site upstream basin delineation with land treatments for a fully developed scenario;
d. 
State all assumptions for the hydrologic analysis;
e. 
Hydrologic analysis:
(1) 
100-year 24-hour flow rate (existing and proposed): see the ordinance codified in this chapter and on file in the town clerk’s office and refer to example in “forms” section;
(2) 
100-year 24-hour volume (existing and proposed): see the ordinance codified in this chapter and on file in the town clerk’s office and refer to example in “forms” section;
f. 
Ponding:
(1) 
Detention ponds: 100-year 24-hour volume and empty in twenty-four (24) hours;
(2) 
Retention ponds: 100-year 24-hour volume and empty in ninety-six (96) hours;
(3) 
Spillways: designed for the 100-year 24-hour flow rate;
(4) 
Pond covenant: private drainage/access easement dedicated to the town;
g. 
Details and calculations for all hydraulic structures;
h. 
Include input and output for all computer generated results;
22. 
Erosion protection: as per basis of proposed design;
23. 
Reference to all supplemental reports, calculations, and attachments on the plan;
24. 
Road maintenance agreement: agreement with the town to develop site access according to standards for access gained from unimproved (not maintained by the town) roadways;
25. 
Please submit three (3) copies of twenty-four inch by thirty-six inch (24" x 36") plans and supplemental material to the code administrator for review. Please allow twenty (20) working days for grading and drainage review.
(Ordinance 97-5, sec. 1-7, adopted 1997)