7500 HARDESON RD 2021-06-09 - Laserfiche WebLink

Design and Installation Specifications . Use in combination with sediment basins or other BMPs. . Maximum slope steepness (normal (perpendicular)to fence line) 1H:1V. . Maximum sheet or overland flow path length to the fence of 100 feet. 1 • Do not allow flows greater than 0.5 cfs. . The geotextile used shall meet the following standards. All geotextile properties lis- I 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)): I Table UI-4. .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-I minimum (ASTM D4491) Grab Tensile Strength 180 lbs. Minimum for extra strength fabric. ' (ASTM D4632) 100 lbs 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 I 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- I ulations. . Refer to Figure 11-4.2.12 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 Western Washington Volume Il-Chapter 4 -Page 370