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<br />7A - ATTACHMENT NO.3 <br />Saltworks Proposal- Water Group Summary Report (22 January 2010) Page 14 <br /> <br />2.2.4 Green Roof Demand <br /> <br />The use of green roofs is planned for a portion of the buildings within the Saltworks <br />project. A green roof is a building rooftop landscaped with vegetation. Green roofs <br />within the Saltworks project were assumed by DMB to be composed of approximately 50 <br />percent high water use plantings and 50 percent low water use plantings, and that up to <br />25 percent of the rooftop area for the residential sector (including the residential/mixed <br />use buildings) may be green roofs. Based on the methodology and results presented in <br />the DMB Demand Report, the anticipated water demand for green roofs is 110 AFY. <br />Green roofs are assumed by DMB to be irrigated with recycled water or other non- <br />potable supplies. <br /> <br />2.2.5 System Losses <br /> <br />The DMB Demand Report includes an assumption for system losses. These losses are <br />estimated for both the potable and recycled water distribution system, and are assumed <br />to be 5 percent of the total demands in both water categories. DMB states that the 5 <br />percent factor is a conservative estimate, and that it is based on the City's potable water <br />system loss estimate of 4 percent reported in its 2005 UWMP. Based on this factor, <br />DMB estimates the total system loss demand for the Saltworks project at 120 AFY. <br /> <br />2.2.6 OMS Water Demand Summary <br /> <br />Based on the information in the preceding sections, the total water demand for the <br />Saltworks project as presented in the DMB Demand Report is as follows: <br /> <br />· Total Indoor Demand - 1,430 AFY (72 percent potable, 28 percent recycled) <br />· Total Outdoor Demand - 960 AFY (100 percent recycled) <br />· Total System Losses - 120 AFY (42 percent potable, 58 percent recycled) <br />· Total Water Demand - 2,510 AFY (43 percent potable, 57 percent recycled) <br /> <br />The DMB Demand Report includes discussion of the significant and complex <br />enforcement measures required to sustain the project demand at the DMB projected <br />levels. Pre-construction and pre-sale actions could include design guidelines, <br />covenants, conditions and restrictions, resale requirements and City staff for inspection <br />and enforcement. Post-sale tactics could include permits for any changed condition on <br />site, assignment of site-specific water budgets and fines for exceeding these budgets, <br />interface at time of sale, and ongoing City staff involvement. <br /> <br />2.3 Redwood City Attachment Q-Based Water Demand <br /> <br />Projections <br /> <br />Redwood City bases its water demand projections on the adopted Redwood City <br />Engineering Standards. The water demand projections criteria are identified within <br />Volume 3, Part VII (Water System Design Criteria), subsection B (Water Demand <br />Projection) of the City's Engineering Standards. This subsection specifies that average <br />day water demand projections for new buildings are to be calculated using "Attachment <br />Q," which is the City's Water Demand Projection Worksheet. Attachment Q calculations <br />are typically used by the City in its preparation of Water Supply Assessments (WSA) for <br />projects that meet the criteria for a WSA. The Saltworks project meets these criteria. <br /> <br />7 <br />