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.
H. Diversions shall not be constructed or
operated to divert water into underground mines without the approval of the
director under
19.8.20.2023
NMAC.
