2006 Water Comprehensive Plan - City of Bellevue

Table 8-1aSummary of Storage EvaluationWest Operating AreaWEST OPERATING AREAProjected Current Projected Projected ProjectedDemand 6-Year Demand 20-Year Demand Buildout DemandYR 2003 YR 2011 YR 2025 YR 2040Demand Summary (gpd) (1)Equivalent Residential Units (ERUs) 29,068 33,414 39,171 45,344 40,321Projected Demand, Current consumption patterns (gpd) (2)Average Day 7,487,849 8,300,000 9,730,000 11,263,391 10,015,701Maximum Day 16,850,000 18,716,667 21,942,500 25,340,000 22,532,989Peak Hour 28,982,000 32,192,667 37,741,100 43,584,800 38,756,742Available Storage (gal) (4)Pikes Peak 550 1,000,000 1,000,000 1,000,000 1,000,000 1,000,000Meydenbauer 1,200,000 1,200,000 1,200,000 1,200,000 1,200,000Woodbridge 397 Standpipe 2,000,000 2,000,000 2,000,000 2,000,000 2,000,000Clyde Hill 465 Standpipe 750,000 750,000 750,000 750,000 750,000Clyde Hill 390 4,000,000 4,000,000 4,000,000 4,000,000 4,000,000Clyde Hill 335 Round 1,000,000 1,000,000 1,000,000 1,000,000 1,000,000Clyde Hill 335 Square 500,000 500,000 500,000 500,000 500,000Cherry Crest 3,000,000 3,000,000 3,000,000 3,000,000 3,000,000Total Available Storage (gal) 13,450,000 13,450,000 13,450,000 13,450,000 13,450,000Storage EvaluationMulti-Source Credit w/ new source 11,088,000 11,516,667 14,742,500 18,140,000 15,332,989Existing SourceRequired Standby Storage (gal) (5) 5,813,547 6,682,770 8,372,000 9,068,753 8,943,402Required Equalizing Storage (gal) (6) 3,370,000 3,743,333 4,388,500 5,068,000 4,506,59820-percent of Maximum Day DemandRequired Fire Flow Storage (gal) (7) 1,650,000 1,650,000 1,650,000 1,650,000 1,650,000Total Required Storage (gal) (8) 10,833,547 12,076,103 14,410,500 15,786,753 15,100,000Storage Surplus/(Deficiency) Existing Source (gal) (10) 2,616,453 1,373,897 (960,500) (2,336,753) N/ANotes:Maximum ERUwith ExistingFacilities) (11)(1) Residential ERUs are calculated based on number of households and 2.8 persons/SFU for current conditions and 2.7 persons/SFU for future conditions. Non-residential flows areconverted to equilvalent ERUs.(2) Projected demands are provided by or interpolated from estimates provided by City of Bellevue staff.(3) Not used.(4) It is assumed that the entire storage volumes are available.(5) Required standby storage is equal to the larger of 200 gallons per ERU or 2 time ADD minus multi-source credit.(6) Required equalizing storage based on larger of 20% of the maximum day demand or the DOH equation (PHD-Source) (gpm) * 150 minutes.(7) Fireflow storage based on largest fireflow the system can reasonably be expected within this area. Based on 5,500 gpm for 5 hrs.(8) Bellevue's system improvement plans include maintaining supply source adequate to meet MDD.(9) Not used.(10) Storage Surplus/(Deficit) is equal to the total available storage minus total required storage minus smaller of fire flow and standby storage.(11) Calculation of Maximum number of ERUs available assuming no new source or storage. If MDD is greater than source, calculation of storage continues assuming no new source hasbeen installed.8-10