Section Env-Wq 1507.05 - Channel Protection Requirements(a) The purpose of this section is to protect channels, downstream receiving waters, and wetlands from erosion and associated sedimentation resulting from urbanization within a watershed.(b) The combined flow to a single water body from a project site shall meet one of the following criteria: (1) The 2-year, 24-hour post-development peak flow rate generated from the proposed disturbance shall be equal to or less than the 2-year, 24-hour pre-development peak flow rate and: a. The 2 year, 24-hour post-development storm volume, directed to the nearest water body has not increased over the pre-development volume by more than 0.1 acre-feet;b. The 2-year, 24-hour post-development peak flow rate directed to the nearest water body is less than 2 cfs; orc. The area directly discharges into a fourth order or greater river, a pond or lake greater than 10 acres, or tidal water;(2) The 2-year, 24-hour post-development peak flow rate shall be less than or equal to 50 percent of the 2-year, 24-hour pre-development peak flow rate; or(3) The 2-year, 24-hour post-development peak flow rate shall be less than or equal to the 1-year, 24-hour pre-development peak flow rate.(c) When determining "equal to or less than", allowances shall be made for scientific uncertainty and mathematical rounding.N.H. Code Admin. R. Env-Wq 1507.05
(See Revision Note #1 at chapter heading for Env-Wq 1500) #9343, eff 1-1-09; (See Revision Note #2 at chapter heading for Env-Wq 1500) amd by #9817-A, eff 12-1-10
Amended by Volume XXXVII Number 32, Filed August 10, 2017, Proposed by #12342, Effective 8/15/2017, Expires 8/15/2027.