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1 <br />� i <br />1 <br />1 <br />1 <br />1 <br />1 <br />A separation geotextile shall be placed under the spalls to prevent fine sediment from <br />pumping up into the rock pad. The geotextile shall meet the following standards: <br />Grab Tensile Strength (ASTM D4751) <br />200 psi min. <br />Grab Tensile Elongation (ASTM D4632) <br />30% max. <br />Mullen Burst Strength (ASTM D3786-80a) <br />400 psi min. <br />AOS (ASTM D4751) <br />20-45 (U.S. standard sieve size) <br />• Consider early installation of the first lift of asphalt in areas that will paved; this can <br />be used as a stabilized entrance. Also consider the installation of excess concrete <br />as a stabilized entrance. During large concrete pours, excess concrete is often <br />available for this purpose. <br />. Fencing (see BMP C103: High Visibility Fence (p.269)) shall be installed as neces- <br />sary to restrict traffic to the construction entrance. <br />. Whenever possible, the entrance shall be constructed on a firm, compacted sub - <br />grade. This can substantially increase the effectiveness of the pad and reduce the <br />need for maintenance. <br />• Construction entrances should avoid crossing existing sidewalks and back of walk <br />drains if at all possible. If a construction entrance must cross a sidewalk or back of <br />walk drain, the full length of the sidewalk and back of walk drain must be covered <br />and protected from sediment leaving the site. <br />Maintenance Standards <br />Quarry spalls shall be added if the pad is no longer in accordance with the spe- <br />cifications. <br />. If the entrance is not preventing sediment from being tracked onto pavement, then <br />alternative measures to keep the streets free of sediment shall be used. This may <br />include replacement/cleaning of the existing quarry spalls, street sweeping, an <br />increase in the dimensions of the entrance, or the installation of a wheel wash. <br />. Any sediment that is tracked onto pavement shall be removed by shoveling or <br />street sweeping. The sediment collected by sweeping shall be removed or sta- <br />bilized on site. The pavement shall not be cleaned by washing down the street, <br />except when high efficiency sweeping is ineffective and there is a threat to public <br />safety. If it is necessary to wash the streets, the construction of a small sump to con- <br />tain the wash water shall be considered. The sediment would then be washed into <br />the sump where it can be controlled. <br />. Perform street sweeping by hand or with a high efficiency sweeper. Do not use a <br />non -high efficiency mechanical sweeper because this creates dust and throws <br />soils into storm systems or conveyance ditches. <br />2014 Stormwater Management Manual for Westem Washington <br />Volume 11 - Chapter 4 - Page 271 <br />