(a) Permanent soil stabilization. All areas of final grade must be permanently stabilized within seven days of reaching final grade. This is usually accomplished by using seed and mulch, but special measures are sometimes required. Permanent stabilization must be specified and performed as listed in Table 3 below:
TABLE 3: PERMANENT STABILIZATION
Area Requiring Permanent Stabilization | Time Frame to Apply Erosion Controls |
Any area that will lie dormant for one year or more. | Within 7 days of the most recent disturbance. |
Any area within 50 feet of a watercourse and at final grade. | Within 2 days of reaching final grade. |
Any area at final grade. | Within 7 days of reaching final grade within that area. |
(1) For slopes steeper than 3:1, erosion control netting, placement of seed and mulch with tackifier, retaining walls, and/or other comparable method shall be utilized. All drainage ditches shall be designed and stabilized with rock riprap, sod, or erosion control matting, as appropriate. If failures occur within these created channels, immediate repair and/or revised design is required. Soil stabilization measures should be selected to be appropriate for the time of year, site conditions, and estimated length of use should include the use of the addition of topsoil, erosion control matting, rock riprap, and/or retaining walls. Permanent seeding should be done March 1 to May 31 and August 1 to September 30. Dormant seeding can be done from November 20 to March 15. At all other times of the year, the area should be temporarily stabilized until a permanent seeding can be applied.
(2) A permanent vegetative cover shall be established on denuded areas not otherwise permanently stabilized. Permanent vegetation shall not be considered established until an 80% ground cover is achieved that is mature enough to control soil erosion satisfactorily and to survive severe weather conditions.
(b) Temporary soil stabilization. Temporary soil stabilization is the most effective BMP during construction. The goal of temporary stabilization is to provide cover, quickly. This is accomplished by seeding with fast growing grasses then covering with straw mulch. Apply only mulch between November 1 and March 31. To minimize costs of temporary stabilization, leave natural cover in place for as long as possible. Only disturb areas where work is anticipated within the next 21 days. Temporary soil stabilization is required and NOT an option. Temporary stabilization must be specified and performed as listed in Table 4 below:
TABLE 4: TEMPORARY STABILIZATION
Area Requiring Temporary Stabilization | Time Frame to Apply Erosion Controls |
Any disturbed area within 50 feet of a watercourse and not at final grade. | Within 2 days of the most recent disturbance, if that area will remain idle for more than 21 days. |
For all construction activities, any disturbed area, including soil stockpiles, that will be dormant for more than 21 days but less than one year, and not within 50 feet to a watercourse. | Within 7 days of the most recent disturbance within the area. |
Disturbed areas that will be idle over the winter. | Prior to November 1. |
NOTE: Where vegetative stabilization techniques may cause structural instability or are otherwise unobtainable, alternative stabilization techniques must be employed. These techniques may include mulching, erosion matting, or placement of stone. | |
(c) Soil stockpiles. Soil stockpiles shall be stabilized with temporary seed and mulch or have perimeter silt fencing place to prevent soil loss. All stockpiles shall be located at least 100 feet from all watercourses, drainage ways, wetlands and site drainage exit points.
(Ord. 15-O-2820, passed 5-19-2015)