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Background. 2010 Spokane River Forum Water Demand Presentations Idaho Future Demand Study Draft Results presentation Spokane County Water Demand Model presentation of project goals, objectives, concepts. Presentation Overview. Spokane County Water Demand Model Idaho Future Demand Study
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Background • 2010 Spokane River Forum Water Demand Presentations • Idaho Future Demand Study Draft Results presentation • Spokane County Water Demand Model presentation of project goals, objectives, concepts.
Presentation Overview • Spokane County Water Demand Model • Idaho Future Demand Study • Study Compatibility
Spokane County Water Demand Model • Segregated by Water Use Sector • each subsector has a unique submodel, or way of calculating water demand
Spokane County Water Demand Model • Segregated Spatially • 487 separate forecast units • A unique water demand calculation is done for each forecast unit
Spokane County Water Demand Model • Segregated in monthly increments
Spokane County Water Demand Model • Disaggregated Model • In each forecast unit(487) there is a calculation for each submodel (13) for each month 12 • 75,972 water demand calculations per year Each forecast unit can have different inputs into each sub model Water demand calculation for each month
Spokane County Water Demand Model • Developed and runs in Excel 2007 • Series of interconnected spreadsheets and formulas
Spokane County Water Demand Model • Single Family Residential Model • Collected 20 years of data from 15 Water Systems: • monthly per connection water use from water systems, • weather data • demographic data • Time Series-Cross Sectional Regression • How does water use vary due to variables that are fixed such as home size. • How does water use vary due to variables that change with time such as weather.
Spokane County Water Demand Model • Single Family Residential Model • Split into two models: • Indoor water use model • Outdoor water use model that adds water to indoor use May through October • Indoor model: • Water use is a function of household income • Outdoor model • Water use is a function of home value, temperature, precipitation, and lot size.
Spokane County Water Demand Model Single Family Residential Model - Example Indoor model r2 = 0.55 Outdoor model r2 = 0.74
Spokane County Water Demand Model Annual Public Water System Use: Modeled vs. Reported Reported in millions of gallons per year
Spokane County Water Demand Model • Impact of weather on water use
Spokane County Water Demand Model • Demand from SVRP Aquifer from Spokane County
Spokane County Water Demand Model • Demand from SVRP Aquifer Reported in billions of gallons per year
Spokane County Water Demand Model • Monthly Demand from SVRP Aquifer from Spokane County 156 CFS difference
Spokane County Water Demand Model no conservation no conservation no conservation • Conservation and Weather • Conservation efforts can be masked by changes in weather
Idaho Future Demand Study • Includes an estimate of current and future use by water use sector on an annual basis: • Public Water Systems • Self Supplied Domestic • Self Supplied Commercial & Industrial • Agriculture • Separates Irrigation and Non-Irrigation Use
Idaho Future Demand Study • Evaluates consumptive vs. non consumptive use • Range of population & employment growth scenarios • Detailed analysis of conservation scenarios • Evaluation of potential climate change impacts
WA & ID Study Compatibility • Water Use by Sector Values in annual acre feet Values are total use
WA & ID Demand • Aquifer Total Demand Idaho scenario – medium growth & no conservation
WA & ID Demand • Additional Work that would enhance compatibility • Idaho: • evaluate demand on a monthly basis • Washington: • Utilize model to: • Develop alternate conservation scenarios • Develop alternate growth scenarios • Estimate consumptive/non consumptive use