1515 132ND ST SE 2022-01-20 - Laserfiche WebLink

Design and Installation Specifications . Use in combination with sediment basins or other BMPs. . Maximum slope steepness (normal (perpendicular) to fence line) 1 H:1 V. . Maximum sheet or overland flow path length to the fence of 100 feet. . Do not allow flows greater than 0.5 cfs. . The geotextile used shall meet the following standards. All geotextile properties lis- ted below are minimum average roll values (i.e., the test result for any sampled roll in a lot shall meet or exceed the values shown in Table II-4.2.3 Geotextile Stand- ards (p.370)): Table II-4.2.3 Geotextile Standards 0.60 mm maximum for slit film woven (#30 sieve). Polymeric Mesh AOS 0.30 mm maximum for all other geotextile types (#50 sieve). (ASTM D4751) 0.15 mm minimum for all fabric types (#100 sieve). Water Permittivity 0.02 sec-1 minimum (ASTM D4491) Grab Tensile Strength 180 lbs. Minimum for extra strength fabric. (ASTM D4632) 100 Ibs minimum for standard strength fabric. Grab Tensile Strength 30%maximum (ASTM D4632) Ultraviolet Resistance 70% minimum (ASTM D4355) . Support standard strength fabrics with wire mesh, chicken wire, 2-inch 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. . 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 120°F. . One -hundred percent biodegradable silt fence is available that is strong, long last- ing, and can be left in place after the project is completed, if permitted by local reg- ulations. . Refer to Figure II-4.2.12 Silt Fence (p.369) for standard silt fence details. Include the following standard Notes for silt fence on construction plans and specifications: 2014 Stormwater Management Manual for Westem Washington Volume ll - Chapter 4 - Page 370