Section 69-05.2-16-06 - Performance standards - Hydrologic balance - Diversion of overland flow Overland flow, including flow through litter, shallow ground water flow from undisturbed areas, and flow in ephemeral streams, may be diverted from disturbed areas by temporary or permanent diversions, if required or approved by the commission. The following requirements must be met for diversions and collection drains used to transport water into treatment facilities and for diversions of overland and shallow ground water flow and ephemeral streams:
1. Temporary diversions must be constructed to pass safely the peak runoff from a ten-year, twenty-four-hour precipitation event, or a larger event as specified by the commission. A two-year recurrence interval may be used for designing collection drains used to transport water into treatment facilities if: a. The diversion will be used for less than one year; or b. The commission determines that the design integrity of the water management plan is maintained during a ten-year, twenty-four-hour design storm. 2. Permanent diversions must be constructed to pass safely the peak runoff from a ten-year, twenty-four-hour precipitation event; however, where necessary to protect fills and property and to avoid danger to public health and safety, permanent diversions must be constructed to pass safely the peak runoff from a one-hundred year, twenty-four-hour precipitation event, or a larger event as specified by the commission. Permanent diversions must be constructed with gently sloping banks stabilized by vegetation. Asphalt, concrete, or other similar linings may be used only when approved by the commission to prevent seepage or to provide stability. 3. Diversions must be designed, constructed, and maintained to prevent 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 maintenance of appropriate gradients, channel lining, revegetation, roughness structures, and detention basins. 4. No diversion shall be located to increase the potential for landslides. No diversion shall be constructed on existing landslides, unless approved by the commission. 5. When no longer needed, each temporary diversion must be removed and the affected land reclaimed. The operator shall reestablish ephemeral stream channels to a longitudinal profile and cross section that approximate premining channel characteristics. 6. Diversion design must incorporate the following: a. Design channel lining using standard engineering practices to pass safely the design velocities. b. Freeboard must be no less than three-tenths of a foot [9.14 centimeters]. Design freeboard may be increased where the area protected is a critical area as determined by the commission. c. Protection for transition of flows and for critical areas such as swales and curves. d. Install energy dissipators 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. e. Dispose of excess excavated material not necessary for diversion channel geometry or channel regrading according to chapter 69-05.2-18. f. Handle suitable plant growth material in compliance with 69-05.2-15. 7. Diversions may not be constructed or operated to divert water into underground mines or an abandoned surface mine without commission approval under section 69-05.2-16-18. N.D. Admin Code 69-05.2-16-06
Effective August 1, 1980; amended effective May 1, 1990; January 1, 1993.General Authority: NDCC 38-14.1-03
Law Implemented: NDCC 38-14.1-24