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<br />7A - ATTACHMENT NO.3 <br />Saltworks Proposal- Water Group Summary Report (22 January 2010) Page 16 <br /> <br />gpd/seat, gpd/feet of street frontage, etc.). For ease in calculation and <br />because these land use types/sizes may change as the Saltworks project <br />progresses through the City review process, these land uses have been <br />aggregated into one category with a demand factor representative of an <br />average demand factor that was used for similar building uses in the Stanford <br />in Redwood City project. This demand factor is 0.55 gpd/sqft. <br /> <br />· Schools - 9 gpcd. The current adopted Attachment Q water demand factor <br />for schools is 35 gpcd. City staff indicated that this value likely includes both <br />indoor and outdoor demand, and has not been evaluated by the City for some <br />time. Historic and present indoor and outdoor water use data for some <br />elementary schools in Redwood City were provided to the water team by City <br />staff (note: the Saltworks project proposes 4 elementary and 1 middle school, <br />so the elementary school water use data were deemed most appropriate for <br />this analysis). Based on these data, about 26 percent of the school water <br />use was estimated to be indoor use and the remaining 74 percent was <br />outdoor use, resulting in the 9 gpcd demand factor used for this analysis. <br />The demand calculation is based on five proposed schools at 800 students <br />and 40 employees each, for a total of 4,200 persons. <br /> <br />For these land use types, the City assumes that 20 percent of indoor water use would be <br />served by recycled water for toilet flushing, and the remaining 80 percent served by <br />potable water. <br /> <br />Based on the revised Attachment Q demand factors described above, the total indoor <br />water demand for these land uses is as follows: <br /> <br />· Office (1 million square feet) - 67 AFY <br />· Retail/Restaurant/Community Facilities (190,000 square feet) - 117 AFY <br />· Schools (4,200 people) - 43 AFY <br />· Total C&llndoor Demand - 227 AFY <br /> <br />2.3.3 Landscape Irrigation Demand <br /> <br />Redwood City uses one demand factor to estimate outdoor landscaping water demand: <br />3.5 cubic feet of water per square foot of landscape per year (cuftlyr). Based on the <br />areas of outdoor landscaping provided in the DMB Demand Report (described <br />previously in Section 2.2.3), the total landscaping water demand for the Saltworks <br />project using the Attachment Q methodology (which includes green roofs) is 1,396 AFY. <br />Green roof water use is not well documented in industry literature nor is there a factor for <br />it in Attachment Q, so the in-ground landscaping demand factor was used for this <br />analysis. <br /> <br />Similar to the DMB demand analysis, the Attachment Q analysis assumes that all <br />outdoor water demands will be served by recycled water, which is consistent with the <br />City's Recycled Water Use Ordinance. <br /> <br />2.3.4 System Losses <br />Redwood City does not assign an Attachment Q value for system loss but incorporates it <br />into the demand factors. <br /> <br />9 <br />