Section Env-Wq 1506.12 - Sediment Control Methods: Temporary Stormwater DiversionTemporary stormwater diversion shall comply with the following:
(a) When necessary to minimize release of sediment-laden runoff prior to stabilization of the site and the permanent stormwater management system components, sediment-laden water shall be diverted and stored in temporary diversion practices such as sediment basins or trenches;(b) Subject to (c), below, temporary diversion practices shall be stabilized prior to receiving runoff;(c) Temporary diversion channels with a gradient of 2 percent or greater shall be stabilized, however channels with a slope of less than 2% shall be stabilized only if erosion is observed;(d) The area draining to each temporary diversion practice shall be less than 5 acres;(e) Temporary diversion channels shall convey, and temporary basins and trenches shall contain, the 2-year, 24 hour design storm without overtopping the banks;(f) The bed slope of diversion channels shall have a positive grade to assure drainage;(g) Where diversions carry concentrated flows, energy dissipation methods shall be implemented to disperse flow into areas downstream of the disturbed area;(h) If erosion of temporary diversion practices occurs during construction, corrective action shall be taken to stabilize the basin, channel, and berm; and(i) Diversion basins and trenches shall be cleared of sediment whenever sediment accumulates.N.H. Code Admin. R. Env-Wq 1506.12
(See Revision Note #1 at chapter heading for Env-Wq 1500) #9343, eff 1-1-09
Amended by Volume XXXVII Number 32, Filed August 10, 2017, Proposed by #12342, Effective 8/15/2017, Expires 8/15/2027.