(A)
The design, construction, and maintenance of all drainage, natural, and erosion control facilities within the City of Elephant Butte shall be performed in accordance with procedures, criteria, and standards formulated by the City Engineer and in accordance with the policies established by this chapter.
(B)
All construction activities within the jurisdiction of the City of Elephant Butte shall conform to the requirements of the City Engineer with respect to drainage and erosion control. Original construction and modifications and or additions to existing structures or facilities constituting less than 500-square feet in plain view are excluded.
(1) Construction, grading, or paving on any lot within the jurisdiction of the City of Elephant Butte shall not increase the damage potential to upstream, downstream, or adjacent properties or public facilities. Damages shall be defined as those caused by flooding from the 100-year design and all smaller storms and from erosion and sedimentation resulting from the 10-year design storm and all smaller storms.
(2) Any grading within or adjacent to a major water course shall provide for erosion control and the safe passage of the 10-year design storm runoff during the construction phase.
(3)
Grading, cut, fill or importation of materials in excess of 500-cubic yards or grading of any area of 1 acre or more shall conform to drainage and erosion control policies and to standards, criteria, and procedures established by the City Engineer. A grading permit, issued by the City Engineer, shall be required for projects involving more than 500-cubic yards of material or 1 acre or more in area. Applications for development of areas known to have been sanitary landfills shall be accompanied by a report which discusses potential health and soil mechanics problems and their solutions. The reports shall be prepared by a registered New Mexico professional engineer, competent in soil mechanics and related health hazards.
(4) Paving or repaving an area larger than 1,000 square feet shall require a paving permit. Applications for a paving permit shall be accompanied by a drainage plan, except for repaving of existing paved areas in which no grading is planned.
(5) The City Engineer shall not issue a grading or paving permit unless the proposed grading or paving is in compliance with the policies and standards of this subchapter or other criteria established as good practices by the industry or the City Engineer.
(C) The city may participate with the private sector, other public bodies, and agencies operating within the jurisdiction of this policy, in order to accomplish the goals and implement the policies adopted in the subchapter. This includes, but shall not be limited to, the development and adoption of master plans, participation in the construction of projects, and exercising control through the planning, platting, zoning, and permitting processes. Projects involving city funding shall be prioritized, funded and scheduled within the guidelines of the CIP and with CIP projects.
(D) It shall be the responsibility of the City Engineer to produce, approve, make, and retain records of all drainage plans, drainage reports, design analysis, design drawings, as-built drawings, and maintenance schedules related to all drainage control, flood control, and erosion control facilities constructed within city rights-of-way or easements.
(E) Applications for all land use changes shall address drainage and erosion control in terms of the interactions of these parameters with other requirements and needs produced by the proposed land use changes.
(F) Requests for the platting of land for the purpose of subdivision or development shall be accompanied by appropriate drainage and erosion control information.
(G) Storm drainage is a critical element in the planning and development of the city and the following measures are to be taken to insure controlled drainage.
(1) The City Engineer shall not approve any plan or report pertaining to proposed construction, platting, or other development where the proposed activity or change in the land affected would result in downstream capacity being exceeded.
(2) Downstream capacity is determined based on the assumption of fully developed watersheds. This assumption prevents “the first come, first served” approach where downstream development unduly constrains upstream development. Parameters used in the determination of downstream capacity include, but are not limited to:
(a) Channel-stability;
(b) Crossing hydraulic capacity;
(c) Retention pond capacity;
(d) Hydraulic capacity of street, drainage ditches, or channels;
(e) Public safety: and
(f) Maintenance constraints.
(3) Planned public storm drainage facilities are assumed as in place in determining downstream capacity, only if construction funds are available and design has progressed to the point where capacity can be ascertained.
(H) Temporary facilities are only allowed and/or required on a case by case basis as determined by the City Engineer. The level of protection provided by temporary facilities shall be determined by considering:
(1) The likelihood and consequences of a failure;
(2) Length of time until permanent facilities will be in place: and
(3) The acceptance of maintenance responsibilities and legal liabilities.
(I) Requests for approval of development and/or platting proposals to the City Engineer shall be accompanied by drainage and erosion control information and/or commitments. The particular nature, location and scope of the proposed development defines the degree of detail. One or more of the following levels of submittal may be required based on the following:
(1) Conceptual grading and drainage plan. A graphic representation of existing and proposed grading, drainage and erosion control information. The information should be of sufficient detail to determine project feasibility. The purposes of this plan are to check the compatibility of the proposed development within grading, drainage, flood hazard, and erosion control constraints as dictated by on-site physical features as well as adjacent properties, streets, alleys, and channels. Modifications to the Comprehensive Plan and the development of area plans, sector plan, site development plans, and landscaping plans on tracts of 5 acres or more are appropriate applications of conceptual grading and drainage plans.
(2) Drainage plans. A detailed presentation required for approval of small, simple development approvals. Drainage plans are prepared in combination with the detailed grading plan and address both on-site and off-site drainage and erosion control issues. Drainage plans are required for building permits, site development plans, and landscaping plans for developments involving less than 5 acres.
(3) Drainage report. A drainage report is a comprehensive analysis of the drainage and erosion control constraints and impacts resulting from a proposed planning, development, or construction project. Drainage reports are required for subdivisions containing more than 10 lots or constituting 5 acres or more, platting or construction within a designated flood hazard area and for any platting or development adjacent to a major arroyo.
(4) Erosion control plan. An erosion control plan is usually incorporated into the drainage plan or drainage report. Erosion control plans address all phases of each project from initial grading through and including final occupancy. Phased projects require special attention. All construction projects, both public and private, within the jurisdiction of this chapter, unless specifically excluded, require an approved erosion control plan prior to start of construction.
(J) Drainage control considerations shall specifically address safety, convenience, and economics for both private property and public facilities.
(K) Design criteria is as follows:
(1) The Elephant Butte 10-year design storm is the 10-year, 24-hour SOS TYPE 11-60 rainfall distribution such that the 1 hour rainfall is set at 60% of the 24-hour rainfall.
(2) All detention and retention basins shall be designed in accordance with the New Mexico State Engineers requirements with respect to maximum retained volumes and evacuation times.
(3) Design circumstances may require that other design storms be considered. The source for rainfall data are current NOAA publications. When the need for other design storms is apparent, the City Engineer will provide requirements concerning appropriate storms, frequencies, and durations.
(L) The City Engineer shall, within 6 weeks after the submission of a written request for the approval of a plat, development plan, drainage submittal, or exemption, approve or deny the request and mail a copy of his or her decision to the applicant. If the request is denied, the reasons for the denial shall be stated in writing. Appeal of the decisions is as provided for in § 154.47 of this chapter.
(M) Grading or paving permits issued by the City Engineer or approvals by the City Engineer of drainage plans, erosion control plans or other improvement plans within the context of this chapter shall expire by limitation and become null and void if the work or improvements authorized is not commenced within 12 months of the approvals. In the event the authorized work or improvement is suspended or abandoned for a period of 8 months after the work or improvement is commenced, the permit or approval shall expire and become null and void. Before the work or improvement is recommenced re-submittals must be made for approval by the City Engineer.
(Ord. 77, passed 1-5-2005; Am. Ord. 194, passed 12-16-2020)