Section Env-Wq 1507.03 - Pollutant Discharge Minimization Requirements(a) Except as required by (b) through (d) below, the stormwater treatment practices described in Env-Wq 1508.03 through Env-Wq 1508.12 shall be acceptable methods for minimizing pollutant discharges to surface waters of the state, provided that the requirements of this section are met along with all method-specific criteria.(b) Except as required by (c) below, any project that would result in a discharge of stormwater within one-quarter mile of a surface water of the state impaired for phosphorus, or within one-quarter mile of a lake or pond, shall include stormwater treatment practice(s) that:(1) Meet the requirements of Env-Wq 1508.07;(2) Meet the requirements of Env-Wq 1508.06 or Env-Wq 1508.08, with the additional requirement that the filter media must be amended with 5% water treatment residuals or 0.5% iron filings;(3) Have pollutant removal efficiencies equal to or greater than (1) or (2) above; or(4) Demonstrates by a pollutant loading analysis that there will be no increase in phosphorus loading to the surface water of the state as a result of the project.(c) Any project that would result in a discharge of stormwater within one-quarter-mile of a Class A surface water or within the watershed of a surface water that is an Outstanding Resource Water (ORW) as defined in Env-Wq 1708.04(a) shall include stormwater treatment practice(s) that meet the requirements of Env-Wq 1508.06 with the additional requirement that the filter media must be amended with 5% water treatment residuals or 0.5% iron filings.(d) Any project that would result in a discharge of stormwater within one-quarter mile of a surface water of the state impaired for nitrogen shall include stormwater treatment practice(s) that meet the requirements of Env-Wq 1508.05 or Env-Wq 1508.06.(e) Stormwater treatment practices shall be accessible for proposed maintenance activities.(f) Infiltration rates for designing stormwater treatment practices shall be determined in accordance Env-Wq 1504.14.(g) Stormwater treatment practices shall meet the water supply well setback criteria identified in Env-Wq 1508.02.(h) Subject to (i) below, stormwater treatment practices shall be designed for the water quality volume (WQV) or water quality flow (WQF), as applicable, calculated in accordance with Env-Wq 1504.10 and Env-Wq 1504.11, respectively.(i) For redevelopment, as defined by Env-Wq 1502.53, except where the project solely consists of activities performed under Env-Wq 1503.03(a) or (b): (1) Stormwater treatment practices for stormwater runoff from existing impervious cover shall be designed for 30 percent or greater of the WQV or WQF, as applicable; and(2) Stormwater treatment practices for pervious areas being converted to impervious cover shall be designed for the WQV or WQF, as applicable.(j) Pollutant loading analysis shall be performed as follows:(1) Load export rates for total nitrogen and total phosphorus shall be as provided in the New Hampshire Small MS4 General Permit, Appendix F; and(2) Pollutant removal efficiencies for total nitrogen and total phosphorus shall be as provided in the New Hampshire Small MS4 General Permit, Appendix F.N.H. Admin. Code § Env-Wq 1507.03
(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.Amended by 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).