North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 04 - SEDIMENTATION CONTROL › Subchapter B - EROSION AND SEDIMENT CONTROL › Section 04B .0132 - DESIGN STANDARDS FOR THE UPPER NEUSE RIVER BASIN (FALLS LAKE WATERSHED)

Current through Register Vol. 39, No. 2, July 15, 2024
In addition to any other requirements of State, federal, and
				  local law, land-disturbing activity in the watershed of the drinking water
				  supply reservoir that meets the applicability requirements of Session Law
				  2009-486, Section 3.(a), shall meet all of the following design standards for
				  sedimentation and erosion control:
(1)
				Erosion and sedimentation control measures, structures, and devices shall be
				planned, designed, and constructed to provide protection from the runoff of the
				25-year storm that produces the maximum peak rate of runoff as calculated
				according to procedures set out in the United States Department of Agriculture,
				Natural Resources Soil Conservation Service's "National Engineering Field
				Handbook 630 for Conservation Practices" or according to procedures adopted by
				any other agency of the State or the United States.
(2) Sediment basins shall be planned,
				designed, and constructed so that the basin will have a settling efficiency of
				at least 70 percent for the 40-micron size soil particle transported into the
				basin by the runoff of the two-year storm that produces the maximum peak rate
				of runoff as calculated according to procedures in the United States Department
				of Agriculture, Natural Resources Soil Conservation Service's "National
				Engineering Field Handbook 630 for Conservation Practices" or according to
				procedures adopted by any other agency of the State or the United
				States.
(3) Newly constructed open
				channels shall be planned, designed, and constructed with side slopes no
				steeper than two horizontal to one vertical if a vegetative cover is used for
				stabilization unless soil conditions permit steeper side slopes or where the
				side slopes are stabilized by using mechanical devices, structural devices, or
				other ditch liners sufficient to restrain accelerated erosion. The angle for
				side slopes shall be sufficient to restrain accelerated erosion, as determined
				by the Division, based on soil conditions.
(4) For an area of land-disturbing activity
				where grading activities have been completed, temporary or permanent ground
				cover sufficient to restrain erosion shall be provided as soon as practicable,
				but not later than seven days after completion of grading. For an area of
				land-disturbing activity where grading activities have not been completed,
				temporary ground cover shall be provided as follows:
(a) For an area with no slope, temporary
				ground cover shall be provided for the area if it has not been disturbed for a
				period of 14 days.
(b) For an area
				of moderate slope, temporary ground cover shall be provided for the area if it
				has not been disturbed for a period of 10 days. For purposes of this Item,
				"moderate slope" means an inclined area, the inclination of which is less than
				or equal to three units of horizontal distance to one unit of vertical
				distance.
(c) For an area of steep
				slope, temporary ground cover shall be provided for the area if it has not been
				disturbed for a period of seven days. For purposes of this Item, "steep slope"
				means an inclined area, the inclination of which is greater than three units of
				horizontal distance to one unit of vertical distance.