2320 RAILWAY AVE INTERWEST CONSTRUCTION INC 2023-06-12

INTER WEST — EVERETT CONTRACTOR'S YARD INTERIM FILL PROJECT ' CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN Sitts & Hill Engineers, Inc. Job Number 17,733 A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM D4751) 200 psi min. Grab Tensile Elongation (ASTM D4632) 30% max. Mullen Burst Strength (ASTM D3786-80a)400 psi min. AOS (ASTM D4751) 2045 (U.S. standard sieve size) Consider early installation of the first lift of asphalt in areas that will paved; this can be used as a stabilized entrance. Also consider the installation of excess concrete as a stabilized entrance. During large concrete pours, excess concrete is often available for this purpose. Fencing (see BMP C103: High Visibility Fence (p.269)) shall be installed as neces- sary to restrict traffic to the construction entrance. Whenever possible, the entrance shall be constructed on a firm, compacted sub - grade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. Construction entrances should avoid crossing existing sidewalks and back of walk drains if at all possible. If a construction entrance must cross a sidewalk or back of walk drain, the full length of the sidewalk and back of walk drain must be covered and protected from sediment leaving the site Maintenance Standards Quarry spalls shall be added if the pad is no longer in accordance with the spe- cifications. If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include replacement/cleaning of the existing quarry spalls, street sweeping, an increase in the dimensions of the entrance. or the installation of a wheel wash. Any sediment that is tracked onto pavement shall be removed by shoveling or street sweeping. The sediment collected by sweeping shall be removed or sta- bilized on site. The pavement shall not be cleaned by washing down the street, except when high efficiency sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, the construction of a small sump to con- tain the wash water shall be considered. The sediment would then be washed into the sump where it can be controlled. Perform street sweeping by hand or with a high efficiency sweeper. Do not use a non -high efficiency mechanical sweeper because this creates dust and throws soils into storm systems or conveyance ditches. 2014 Stormwater Management Manual for Western Washington Volume ll - Chapter 4 - Page 271 SITTS & HILL ENGINEERS, INC. 26 ' TACOMA, WASHINGTON