3322 BROADWAY COMPASS HEALTH 2025-10-03

Element 9: Control Pollutants (2.1.9) The site is located inside a Critical Aquifer Recharge Area, as defined by the City of Sammamish. Therefore, pollutants must be contained as much as possible to prevent contaminated runoff, The following pollutants are anticipated to be present on -site: Table 1— Pollutants Pollutant (and source, if applicable) Fuel, Oils and Lubricants Construction waste Concrete waste Chemicals such as fertilizers and pesticides List and describe BMPs: BMP C151 Concrete Handling: Process water and slurry resulting from concrete work will be prevented from entering the waters of the state by implementing concrete handling measures. Tool and equipment cleaning will be done inside a designated concrete washout area (BMP C154). Poured concrete must be covered with plastic to prevent direct runoff from rainfall causing washout. BMP C152 Saw cutting and Surfacing Pollution Prevention: While saw cutting proper steps must be taken to ensure the slurry and does not enter the storm system (concrete saw and vacuum combination system, sandbags, etc.). BMP C153 Material Delivery, Storage and Containment: All chemicals shall have cover, containment, and protection provided on site. Such that leaks from pollutant containers are captured and prevented from mixing the site runoff and infiltrating (for example a tub with plastic covering). BMP C154 Concrete Washout Area: A contained, and controlled area shall be provided for the purpose of cleaning concrete tools and chutes such that the dirty water does not enter a clean runoff system. All pollutants, including waste materials and demolition debris, which occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well organized, and free of debris. If required, BMPs to be implemented to control specific sources of pollutants are discussed below.