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11, <br />r <br />1 <br />Approved as Equivalent <br />Ecology has approved products as able to meet the requirements of BMP C105: Stab- <br />ilized Construction Entrance / Exit. The products did not pass through the Technology <br />Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to <br />accept this product approved as equivalent, or may require additional testing prior to con- <br />sideration for local use. The products are available for review on Ecology's website at <br />http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html <br />BMP C106: Wheel Wash <br />Purpose <br />Wheel washes reduce the amount of sediment transported onto paved roads by motor <br />vehicles. <br />i <br />Conditions of Use <br />When a stabilized construction entrance (see BMP C105: Stabilized Construction <br />Entrance / Exit (p.270)) is not preventing sediment from being tracked onto pavement. <br />. Wheel washing generally is enerall an effective BMP when installed with careful attention <br />to topography. For example, a wheel wash can be detrimental if installed at the top <br />of a slope abutting a right-of-way where the water from the dripping truck can run <br />unimpeded into the street. <br />. Pressure washing combined with an adequately sized and surfaced pad with dir- <br />ect drainage to a large 10-foot x 10-foot sump can be very effective. <br />. Discharge wheel wash or tire bath wastewater to a separate on -site treatment sys- <br />tem that prevents discharge to surface water, such as closed -loop recirculation or <br />i <br />upland land application, or to the sanitary sewer with local sewer district approval. <br />. Wheel wash or tire bath wastewater should not include wastewater from concrete <br />washout areas. <br />Design and Installation Specifications <br />Suggested details are shown in Figure II-4.1.2 Wheel Wash (p.276). The Local Per- <br />mitting Authority may allow other designs. A minimum of 6 inches of asphalt treated base <br />(ATB) over crushed base material or 8 inches over a good subgrade is recommended to <br />pave the wheel wash. <br />Use a low clearance truck to test the wheel wash before paving. Either a belly dump or <br />lowboy will work well to test clearance. <br />Keep the water level from 12 to 14 inches deep to avoid damage to truck hubs and filling <br />the truck tongues with water. <br />2014 Stormwater Management Manual for Western Washington <br />Volume /I - Chapter 4 - Page 274 <br />