N.M. Admin. Code § 19.8.20.2012

Current through Register Vol. 36, No. 1, January 14, 2025

Section 19.8.20.2012 - HYDROLOGIC BALANCE: STREAM CHANNEL DIVERSIONS

A. Diversions from perennial and intermittent streams within the permit area shall be approved by the director, if he finds that the diversions comply with:

(1) the requirements of Subsection A of 19.8.20.2025 NMAC and Subsection A of 19.8.20.2011 NMAC;

(2) local, state and federal statutes and regulations; and

(3) The diversion will not impair water quantity and quality and will not adversely affect related environmental resources of the stream.

B. When streamflow is allowed to be diverted, the stream channel diversion shall be designed, constructed, and removed in accordance with the following:

(1) The longitudinal profile of the stream, the channel, and the flood-plain shall be designed and constructed to remain stable and to prevent, to the extent possible using the best technology currently available, additional contributions of suspended solids to streamflow or to runoff outside the permit area. These contributions shall not be excess of requirements of state or federal law. Erosion control structures such as channel lining structures, retention basins, and artificial channel roughness structures shall be used in diversions only when approved by the director as being necessary to control erosion. These structures shall be approved for permanent diversions only where they are stable and will require infrequent maintenance.

(2) The combination of channel, bank, and flood-plain configurations shall be adequate to pass safely the peak runoff of a 10-year, 24-hour precipitation event for temporary diversions, a 100-year, 24-hour precipitation event for permanent diversions, or larger events specified by the director. However, the capacity of the channel itself should be at least equal to the capacity of the unmodified stream channel immediately upstream and downstream of the diversion.

C. The design and construction of all stream channel diversions of perennial and intermittent streams shall be certified by a qualified registered professional engineer as meeting the performance standards of 19.8.20 NMAC and any design criteria set by the director.

D. When no longer needed to achieve the purpose for which they were authorized, all temporary stream channel diversions shall be removed and the affected land regraded and revegetated, in accordance with 19.8.20.2007, 2008, 2054 through 2058, and 2060 through 2066 NMAC. At the time diversions were removed, downstream water treatment facilities previously protected by the diversion shall be modified or removed to prevent overtopping or failure of the facilities. The requirement shall not relieve the person who conducts the surface coal mining operations from maintenance of a water treatment facility otherwise required under 19.8.20 NMAC or the permit.

E. When permanent diversions are constructed or stream channels restored, after temporary diversions, the operator shall:

(1) restore, enhance where practicable, or maintain natural riparian vegetation on the banks of the stream;

(2) establish or restore the stream to a longitudinal plan and profile, gradient and cross-section, including aquatic habitats (usually a pattern, of riffles, pools, and drops rather than uniform depth) that approximate premining stream channel characteristics.

N.M. Admin. Code § 19.8.20.2012

11-29-97; 19.8.20.2012 NMAC - Rn, 19 NMAC 8.2.20.2012, 9-29-2000