New Hampshire Code of Administrative Rules
Env - Department of Environmental Services
Subtitle Env-Wq - Water Quality and Quantity Programs
Chapter Env-Wq 1500 - ALTERATION OF TERRAIN
Part Env-Wq 1506 - METHODS FOR EROSION AND SEDIMENT CONTROL DURING TERRAIN ALTERATION ACTIVITIES
Section Env-Wq 1506.10 - Sediment Control Methods: Temporary Sediment Trap

(a) The trap shall be installed as close to the disturbed area or source of sediment as possible;

(b) The maximum contributing drainage area to the trap shall be less than 5 acres;

(c) Except as required by Env-Wq 1511.07 for solar arrays, the minimum volume of the trap shall be 3,600 cubic feet of storage for each acre of drainage area;

(d) The side slopes of the trap shall be 3:1 or flatter, and shall be stabilized immediately after their construction;

(e) The outlet of the trap shall be a minimum of one foot below the crest of the trap and shall discharge to a stabilized area;

(f) The trap shall be cleaned when 50 percent of the original volume is filled; and

(g) The materials removed from the trap shall be properly disposed of and stabilized.