7400 HARDESON RD 2018-01-02 MF Import

S.6 PUBLIC WATER SIJPPLIES 8.6.1 Threshold The analysis in the Water System Plan projected the overall future peak-hour demand for the area at 2.7 gpm/acre (approximately 4,000 gpa/day peak flow), and assumed fire flow requirements of approxima[ely 3,500 gpm for commercial and industriaUmanufacturing uses. Based upon the proposed design of the water system, any development using more than 2.7 gpm/acre has the potential to affect water pressure on other sites. Additiunal analysis will be required for development proposals with a peak hour demand above 2.7 gpm/acre and/or a fire flow requirement of 3,500 gpm or greater. The additional analysis may be as simple as calculations completed by the Public Works Department prior to a pre-application meeting on a specific development proposal. The additional analysis must determine how the proposal's water demand will affect the entire water supply and distribution system. Projects with no additional major improvements needed and no adverse cumulative impacts on the water supply and distribution system aze covered by this analysis. The 2.7 gpm/acre is an overall average peak hour demand assumed for planning in large azeas such as the study area. However, there will undoubtedly be site-specific proposals with larger demand. For example, large irrigation systems can exceed 50 gpm/acre demand. Other land uses with demands much lower than 2.7 gpm/acre, such as warehouses, are assumed to occur to offset the higher demand land uses, resulting in an overall azea wide average of 2.7 gpm/acre. The impacts of construction of the new water line to service development west of Japanese Gulch were not covercd in the EIS. Additional SEPA analysis is required to review altemative routes for the line which wili minimize the impacts of the proposal. 8.6.3 Mitigation 111easures 1. Looped water mains may be required for some sites to meet fire flow requirements and to protect water quality. Pressure reducing valves may be requircd when �ooped systems are constructed. (SEYA Public Services and Utilities Policies) 2. Developments must construct improvements necessary to provide a water pressure of 40-80 psi under normal operating conditions as required by Public Works. (SEPA Public Services and Utilities Policies) 3. Recycling of runoff water &om bus or truck washing facilities is required. (SEPA Public Services and Utilities Policies) 4. New water system facilities must avoid environmentally sensitive areas to the maximum extent possible. Where �vater lines must be constructed through enviro�unentally sensitive areas, best management practices must be followed. (Sce the mitigation measures discussed in Section 4) (SEPA Earth, Water, and Plant and Animal Policies) 19 �