55C - WATER SUPPLY ASSESSMENT FOR MAINPLACE

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City of Santa Ana MainPlace Mall Transformation Water Supply Assessment 4.6 Project Water Demand The City of Santa Ana uses the following factors to determine water usage: • Single Family: 130 gpd/capita Multiple Family: 120 gpd/capita High -Rise Residential: 110 gpd/capita • Commercial Recreational (hotels/motels): 180 gpd/room • Commercial: 2,500 gpd/acre (Includes office and retail uses) • Industrial: 3,500 gpd/acre • Open Space / Parks / Landscape Areas: 3,000 gpd/acre Due to the nature and density of the Project, and the uncertainty of residential unit mix, per capita averages and per acre averages are less feasible to use for calculations. Also, since the commercial development on -site is more intense than a typical commercial site, as defined in the Santa Ana zoning ordinance, the commercial water demand factor should be adjusted. For the residential component of the Project, a demand factor of 190 gpd per multi -family unit is used in lieu of the City's standard per capita usage rate because the number of residents that would occupy units on the project site is unknown. The 190 gpd per multi -family unit demand factor is consistent with the demand factors in the MWDOC Orange County Water Reliability Study. The commercial water usage rate per acre is typically based on an assumed Floor Area Ratio (FAR). The City of Santa Ana General Plan Land Use Element identifies a baseline FAR for commercial development of 0.5. Because the City's typical FAR assumption does not reflect the commercial development intensity on the site, an "equivalent" Project acreage has been calculated based on the Project's proposed commercial (retail plus office) square footage. The adjusted (increased) acreage was multiplied by the 2,500 gpd/acre typical generation rate to account for the water usage associated with this level of project intensity. The existing mall square footage was subtracted from the equivalent acreage calculation because the existing mall's water usage and projected use was previously included in the baseline UWMP demands and is therefore not an additional demand. The equivalent acreage calculation is as follows: Total Retail: 1,400,000 sf total—1,113,000 sf existing mall = 287,000 additional sf Total Office: 750,000 sf Total Commercial Space: 750,000 sf+ 287,000 sf = 1,037,000 sf Equivalent Acreage: 47.6 acres Kimleyvftrn 55 Page 120