931 BROADWAY TEUTSCH STUDENT HOUSING 2018-03-07

CITY OF EVERETT STORMWATER MANAGEMENT MANUAL Table 3.10 Geotextile Standards for Silt Fences Polymeric Mesh AOS (ASTM 0.60 mm maximum for film woven (#30 sieve). 0.30 mm D4751) maximum for all other geotextile types (#50 sieve). 0.15 mm minimum for all fabric types (#100 sieve). Water Permittivity (ASTM D4491) 0.02 sec' minimum Grab Tensile Strength (ASTM 180 Ibs. Minimum for extra strength fabric. D4632) 100 Ibs minimum for standard strength fabric. Grab Tensile Strength (ASTM 30% maximum D4632) Ultraviolet Resistance (ASTM 70% minimum • D4355) . 6. Standard strength fabrics shall be supported with wire mesh, chicken wire, 2 x 2-inch wire, safety . fence, or jute mesh to increase the strength of the fabric. Silt fence materials are available that have synthetic mesh backing attached. 7. Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum of six months of expected usable construction life at a temperature range of 0°F to l 20°F. 8. 100 percent biodegradable silt fence is available that is strong, long lasting, and can be left in place after the project is completed, if permitted by local regulations. 9. The contractor shall install and maintain temparary silt fences at the locations shown in the plans. The silt fences shall be constructed in the areas of clearing, grading, or drainage prior to starting those activities. A silt fence shall not be considered temporary if the silt fence must function beyond the life of the contract. The silt fence shall prevent soil carried by runoff water from going beneath, through, or over the top of�the silt fence, but shall allow the water to pass through the fence. 10. The minimum height of the top of silt fence shall be 2 feet and the maximum height shall be 2.5 feet above the original ground surface. 1 1. The geotextile shall be sewn together at the point of�manufacture, or at an approved location as determined by the engineer,to form geotextile lengths as required. All sewn seams shall be located at a support post. Alternatively, two sections of silt fence can be overlapped, provided the contractor can demonstrate, to the satisfaction of the engineer, that the overlap is long enough and • that the adjacent fence sections are close enough together to prevent silt laden water from ' escaping through the fence at the overlap. . 12. The geotextile shall be attached on the up-slope side of the posts and support system with staples, _ wire, or in accordance with the manufacturer's recommendations. The geotextile shall be attached to the posts in a manner that reduces the potential for geotextile tearing at the staples, wire, or other connection device. Silt fence back-up support for the geotextile in the form of a wire or plastic mesh is dependent on the properties of the geotextile selected for use. If wire or plastic back-up mesh is used, the mesh shall be fastened securely to the up-slope of the posts with the geotextile being up-slope of the mesh back-up support. 13. The geotextile at the bottom of the fence shall be buried in a trench to a minimum depth of 4 inches below the ground surface. The trench shall be backfilled and the soil tamped in place over the buried portion of the geotextile, such that no flow can pass beneath the fence and scouring cannot occur. When wire or polymeric back-up support mesh is used,the wire or polymeric mesh shall extend into the trench a minimum of 3 inches. Volume 1!— Construction Stormwater Pollution Prevention 3-55