Section Env-Wq 1511.07 - Stable Channel Calculations and Design, Benching(a) When runoff from panels will not discharge as sheet flow pursuant to Env-Wq 1511.05, channel design calculations in accordance with the National Engineering Handbook, Part 654 Stream Restoration Design, Chapter 8 Threshold Channel Design, available as noted in Appendix B, shall be submitted when: (1) Flow paths exceed 300 feet for slopes of 8% or greater, but less than 15%; and(2) Flow paths exceed 100 feet for slopes above 15%.(b) The plans shall show protective lining of concentrated flow paths as necessary when calculated velocities exceed the velocities for a vegetated surface, as determined with the reference in (a) above.(c) When panels are placed on slopes greater than 25%, the slopes shall be terraced and benched as required by Env-Wq 1508.21.N.H. Admin. Code § Env-Wq 1511.07
Derived from Number 41, Filed October 12, 2023, Proposed by #13758, Effective 9/28/2023, Expires 9/28/2033 (see Revision Note #4 at chapter heading for Env-Wq 1500).