N.H. Code Admin. R. Env-Wq 1506.04

Current through Register No. 25, June 20, 2024

Section Env-Wq 1506.04 - Sediment Control Methods: Silt Fences

The use of silt fences shall comply with the following:

(a) Fences shall be used in areas where erosion will occur only in the form of sheet erosion and there is no concentration of water in a channel or other drainage way above the fence;

(b) The maximum contributing drainage area above the fence shall be less than ¼-acre per 100 linear feet of fence;

(c) The maximum length of the slope above the fence shall be 100 feet;

(d) The maximum slope of the area above the fence shall be 2:1;

(e) Fences shall be installed as follows:

(1) Fences shall follow the contour of the land as closely as possible;

(2) The ends of the fence shall be flared up-slope;

(3) The base of the fence shall be:

a. Folded such that not less than 4 inches of the fence is placed along the bottom of a trench that is excavated at least 4 inches deep into the ground, with the soil compacted over the embedded fabric; or

b. If site conditions include frozen ground, ledge, or the presence of heavy roots, embedded in a minimum thickness of 8 inches of ¾-inch stone;

(4) Support posts shall be sized and anchored according to the manufacturer's instructions; and

(5) Adjoining sections of the fence shall be overlapped by 6 inches, folded and stapled to a support post;

(f) Fences shall be inspected and maintained immediately after each rainfall and at least daily during prolonged rainfall; and

(g) Sediment that accumulates at the fence shall be removed with sufficient frequency to prevent the depth of the sediment from reaching one-third the height of the fence.

N.H. Code Admin. R. Env-Wq 1506.04

(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.