Agenda - 04-29-2004-2a - Laserfiche WebLink

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THE IMPORTANCE OF WATER REUSE AS A WATER SUPPLY STRATEGY The graph below illustrates the effects of the planned water reuse system on OWASA's total raw water demand; i e, on the need to withdraw water from die Cane Creek/University Lake /Stone Quarry reservoir system The solid diamonds represent actual raw water demand since 1980; the dashed line is the "expected" demand curve previously reported in OWASA's 2001 Comprehensive Water and Sewer Master Platt, the solid green and red lines are the revised demand projections (with and without reuse) based on more recent forecasts, including detailed University development plans that were not available in 2001. The solid black step- shaped lines represent the capacity of OWASA's reservoir system under existing and future stages of development and under estimated 30 -year recurrence and drought -of- record (2002) conditions the capacity under "Existing System" is the estimated combined 30 -year safe yield of Cane Creek Reservoir, University Lake, and the existing Stone Quarry Reservoir with existing raw water pumping and transmission capacities. The capacity of "Quarry Pump Improvements" shows the estimated combined 30 -year safe yield of Cane Creek Reservoir, University Lake, and existing Stone Quarry Reservoir with existing raw water transmission capacities and the planned upgrade of the Stone Quarry Reservoir pumping station. This new pump station will allow us to more effectively use the supply available from the existing Stone Quarry Reservoir. The capacity under "3 BG Quarry" shows the estimated combined 30 -year safe yield of Cane Creek Reservoir, University Lake, and the enlarged Stone Quarry Reservoir (capacity of 3 billion gallons) with proposed long -term raw water pumping and transmission capacities. The green and red stars indicate the dates at which average demands are expected to equal the system capacity under 30 -year drought conditions — with and without reuse, The horizontal distance between the stars illustrates that reuse can defer the need for an additional water supply source, such as Jordan Lake, by approximately 10 to 12 years. With increased water conservation and reuse, under most hydrologic conditions OWASA's existing water supply sources may be adequate to meet the projected demand for water between now and the time the expanded Stone Quarry Reservoir comes on -line in the mid- 2030s. 20 I 1101' m 16 C- 14 O U) 12 C 0 10 F= Raw Water Supply, Demand, and Potential Deficits Under 30 -Yr Safe Yield and Drouqht- of- Record Conditions Existing! Quarry Pump Improvements 3 BG Quarry 70 -Yr Safe Yield With Reuse Without Reuse -' "' Master Plan "Expected Growth" Drou�tit -- 30 -Yr Safe Yield _ 2002 Drauaht ..✓'- _ Jw"- &�+ .lordan Lake (or other supply alternative) Needed When Avg Day Demand =30-yr Safe ®� moo Yield A 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045