Environment & Sustainability | Environmentally Critical Areas
in the Western Washington Stormwater Manual (2005), or other technical guidance as approved by the City. d. To prevent groundwater contamination, storm water infiltration may be prohibited for all or a portion of a site that includes use of hazardous substances. 2. Groundwater Quality Protection Standards. The following provisions shall apply to development in all CARA classes: a. Activities may only be permitted in a critical aquifer recharge area if the proposed activity will not result in a significant increased risk of contamination of drinking water supplies; b. The City shall impose development conditions when necessary to prevent degradation of groundwater. Conditions to permits shall be based on known, available and reasonable methods of prevention, control and treatment; and c. The proposed activity must comply with the water source protection requirements and recommendations of the Federal Environmental Protection Agency, State Department of Ecology, State Department of Health, and the Seattle-King County health district. 3. Regulation of Facilities Handling and Storing Hazardous Materials Regulated by the State Department of Ecology. a. New and existing commercial and industrial land uses and activities located in Class 1 and Class 2 CARAs shall submit a hazardous materials inventory statement with a development proposal.
b. Report Requirement. Commercial and industrial land uses and activities that involve the use, storage, transport or disposal of hazardous materials as regulated by the state of Washington, in quantities equal to or greater than 20 gallons or the equivalent of 200 pounds, located in Class 1 and Class 2 CARAs, shall submit a critical areas study in accordance with SDC 21.03.020K.3. including, as necessary, a hydrogeologic critical area assessment report, spill containment and response plan and/or groundwater monitoring plan, except for the following uses/activities: i. Retail sale of containers five gallons or less in size, where there are less than 500 total gallons; and
ii. Hazardous materials of no risk to the aquifer.
c. A hydrogeologic critical area assessment report, when required by subsection 3.b. of this section, shall be prepared by a qualified professional to determine potential impacts of contaminants on the aquifer. The report shall include the following site- and proposal- related information, at a minimum: i. Information regarding geologic and hydrogeologic characteristics of the site including the surface location of all CARA classes located on site or immediately adjacent to the site and permeability of the unsaturated/vadose zone;
ii. Groundwater depth, flow direction and gradient;
iii. Data on wells and springs within 1,300 feet of the project area;
88 | Title 21: Sammamish Development Code
Effective | January 1, 2022
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