2006 Water Comprehensive Plan - City of Bellevue
2006 Water Comprehensive Plan - City of Bellevue
2006 Water Comprehensive Plan - City of Bellevue
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Table 4-4b shows total demand forecasts adjusted to include future conservation. Table 4-5shows the additional average day demand savings which are projected to result from futureconservation.Table 4-5Conservation <strong>Water</strong> Savings Over 2003 ADD Levelsby Operating Area(all values in mgd)Operating Area 2011 2025 2040 (build-out)West <strong>Bellevue</strong> 0.44 0.61 0.71East <strong>Bellevue</strong> 0.48 0.48 0.49South <strong>Bellevue</strong> 0.21 0.22 0.23Total 1.13 1.31 1.44Note: no conservation adjustments have been made to wheeled/wholesale customer water useVARIATIONS IN DEMAND<strong>Water</strong> demand variations occur throughout the day and can be shown on a diurnal demand curvewhich plots the percentage <strong>of</strong> daily demand versus time. Figure 4-1 is taken from <strong>Bellevue</strong>’s1992 <strong>Comprehensive</strong> <strong>Plan</strong> and illustrates how water use varies over a 24-hour time period in<strong>Bellevue</strong>, based on maximum day demand (MDD) conditions. Usage patterns for two majoruser groups are shown: residential and commercial. A city-wide composite usage pattern isalso shown. The curves for residential and commercial users are based on hourly demands as aratio to 24-hour MDD within each respective group. Therefore, the peak hour-to-MDD ratioamong residential users only is higher (almost 2.0) than for the composite curve, which isapproximately 1.80. <strong>Bellevue</strong>'s pattern <strong>of</strong> use is similar to that <strong>of</strong> other communities on theEastside.Table 4-6 compares planning numbers for <strong>Bellevue</strong> with those identified by other Eastside communitiesin their most recent water comprehensive plans. As part <strong>of</strong> the work on <strong>Bellevue</strong>’s1992 <strong>Comprehensive</strong> <strong>Plan</strong>, a limited amount <strong>of</strong> data was obtained from spot checks <strong>of</strong> isolatedareas. This data showed that <strong>Bellevue</strong> has experienced peak-hour to MDD peaking factors <strong>of</strong>1.50 to 1.87. The continuing implementation <strong>of</strong> conservation measures since that time may haveresulted in a slight reduction in this peaking factor since 1992. In general, water usage patternsare not thought to have changed significantly from those used in the 1992 <strong>Plan</strong>. The <strong>City</strong> istherefore continuing to use a peaking factor <strong>of</strong> 1.80, which represents the magnitude <strong>of</strong> theevening peak with respect to the MDD, in its hydraulic analysis <strong>of</strong> the water system.4-12
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