New Mexico Administrative Code › Title 19 - NATURAL RESOURCES AND WILDLIFE › Chapter 8 - COAL MINING › Part 20 - PERFORMANCE STANDARDS - SURFACE COAL MINING OPERATIONS › Section 19.8.20.2011 - HYDROLOGIC BALANCE: DIVERSIONS AND CONVEYANCE OF OVERLAND FLOW AND SHALLOW GROUND WATER FLOW AND EPHEMERAL STREAMS

Current through Register Vol. 35, No. 13, July 16, 2024
Overland flow, including flow through litter, and shallow
				  ground water flow from undisturbed areas, and flow in ephemeral streams, may be
				  diverted away from disturbed areas by means of temporary or permanent
				  diversions, if required or approved by the director as necessary to minimize
				  erosion, to reduce the volume of water to be treated, and to prevent or remove
				  water from contact with acid-forming or toxic-forming materials. The following
				  requirements shall be met for all diversions and for all collection drains that
				  are used to transport water into water-treatment facilities and for all
				  diversions of overland and shallow ground water flow and ephemeral
				  streams.
A. All diversions shall be
				designed, constructed and maintained to minimize adverse impacts to the
				hydrologic balance within the permit and adjacent areas, to prevent material
				damage outside the permit area and to assure the safety of the
				public.
B. Temporary diversions
				shall be constructed to safely pass the peak runoff from a 2-year, 24-hour
				precipitation event or a larger event as specified by the director.
C. To protect fills and property and to avoid
				danger to public health and safety, permanent diversions shall be constructed
				to safely pass the peak runoff from a 10-year, 24-hour precipitation event, or
				larger as specified by the director. Permanent diversions shall be constructed
				with gently sloping banks that are stabilized by vegetation. Asphalt, concrete,
				or other similar linings shall be used only when approved by the director to
				prevent seepage or to provide stability.
D. Diversions shall be designed, constructed,
				and maintained in a manner which prevents additional contributions of suspended
				solids to streamflow and to runoff outside the permit area, to the extent
				possible using the best technology currently available. Appropriate sediment
				control measures for these diversions may include, but not be limited to,
				maintenance of appropriate gradients, channel lining, revegetation, roughness
				structures, and detention basins.
E. No diversion shall be located so as to
				increase the potential for land slides. No diversion shall be constructed on
				existing land slides, unless approved by the director.
F. When no longer needed, each temporary
				diversion shall be removed and the affected land regraded, topdressed, and
				revegetated in accordance with 19.8.20.2007, 2008, 2054 through 2059, and 2060
				through 2066 NMAC.
G. Diversion
				design shall incorporate the following.
(1)
				Channel lining shall be designed using standard engineering practices to pass
				safely the design velocities. Rip rap shall be required where necessary to
				control erosion.
(2) Freeboard
				shall be no less than 0.3 feet. Protection shall be provided for transition of
				flows and for critical areas such as swales and curves. Where the area
				protected is a critical area as determined by the director, the design
				freeboard may be increased.
(3)
				Energy dissipators shall be installed when necessary at discharge points, where
				diversions intersect with natural streams and exit velocity of the diversion
				ditch flow is greater than that of the receiving stream.
(4) Excess excavated material not necessary
				for diversion channel geometry or regrading of the channel shall be disposed of
				in accordance with 19.8.20.2034 through 2037 NMAC.
(5) Topdressing shall be handled in
				compliance with 19.8.20.2004 through 2008 NMAC.