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 1505 - REQUIREMENTS TO PROTECT WATER QUALITY DURING TERRAIN ALTERATION ACTIVITIES
Section Env-Wq 1505.06 - Cold Weather Site Stabilization
Current through Register No. 13, March 27, 2025
(a) To adequately protect water quality during cold weather and during spring runoff, the additional stabilization techniques specified in this section shall be employed during the period from October 15 through May 1.
(b) Subject to (c), below, the area of exposed, unstabilized soil shall be:
(c) The allowable area of exposed soil may be increased if a winter construction plan is developed by a qualified engineer or a CPESC specialist and submitted to the department for approval as a request to waive the one-acre limit.
(d) Subject to (f) and (g), below, all proposed vegetated areas having a slope of less than 15% that do not exhibit a minimum of 85% vegetative growth by October 15, or that are disturbed after October 15, shall be seeded and covered with 3 to 4 tons of hay or straw mulch per acre secured with anchored netting or tackifier or with at least 2 inches of erosion control mix meeting the criteria of Env-Wq 1506.05(b).
(e) Subject to (f) and (g), below, all proposed vegetated areas having a slope of 15% or greater that do not exhibit a minimum of 85% vegetative growth by October 15, or that are disturbed after October 15, shall be seeded and covered with a properly installed and anchored erosion control blanket or with at least 4 inches of erosion control mix meeting the criteria of Env-Wq 1506.05(b).
(f) Anchored hay mulch or erosion control mix that meets the criteria of Env-Wq 1506.05(b) shall not be installed over snow greater than one inch in depth.
(g) Erosion control blankets shall not be installed over snow greater than one inch in depth or on frozen ground.
(h) All proposed stabilization in accordance with (d) or (e), above, shall be completed within a day of establishing the grade that is final or that otherwise will exist for more than 5 days.
(i) All ditches or swales that do not exhibit a minimum of 85% vegetative growth by October 15, or that are disturbed after October 15, shall be stabilized temporarily with stone or erosion control blankets appropriate for the design flow conditions, as determined by the owner's engineering consultant.
(j) After October 15, incomplete road or parking areas where active construction of the road or parking area has stopped for the winter season shall be protected with a minimum 3-inch layer of base course gravels meeting the gradation requirements of NHDOT Standard Specification for Road and Bridge Construction, 2016, Table 304-1, Item No. 304.1, 304.2, or 304.3, available as noted in Appendix B.
