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Eastern San Joaquin Groundwater Basin Groundwater Management Plan
<br /> Table 2-4 Future Urban Water Demands
<br /> "1996" Water Use/ Net Increase
<br /> Current Current Land 4 Future Land Future
<br /> City s Acre in Demand
<br /> Demand Use(acres) (af/ac) Use(acres) Demand (af) (af)
<br /> (af)
<br /> Escalon 1,400 932 1.5 2,106 3,200 1,800
<br /> Lathrop' 2,900 3,409 0.85 13,254 11,300 8,400
<br /> Lodi 16,600 6,071 2.7 9,650 26,400 9,800
<br /> Manteca 11,200 5,056 2.2 14,140 31,300 20,100
<br /> Ripon 3,500 1,764 2.0 6,676 13,200 9,700
<br /> Stockton 2 47,000 29,746 1.6 61,353 96,900 49,900
<br /> Total 82,600 241,100 146,600
<br /> Source:San Joaquin County Water Management Plan Volume I
<br /> Notes:
<br /> 1. Lathrop water use per acre is lower than the remainder of the cities because their developments are less dense than
<br /> other cities.The city's future projections indicate that their water use per acre will increase to 1.4 ac-ft/ac.To maintain
<br /> consistency,the water use per acre has been calculated as if it will stay the same over time. It is difficult to predict how
<br /> development patterns will change,and the error that could be associated with this assumption is less than 0.5 percent
<br /> of the future County demand.
<br /> 2. The demand for the city of Stockton only reflects the water use within city limits. Water providers for the Stockton area
<br /> also provide significant water to the urban areas outside of the city limits. Total water deliveries for the Stockton urban
<br /> area are approximately 62,000 ac-ft.
<br /> 3. Current year represents"1996". Individual city water usage data is based on information gathered during the
<br /> development of the San Joaquin County Water Management Plan,2001.
<br /> 4. Water usage on a per acre basis is used to simulate groundwater withdrawals in the Camp Dresser&McKee
<br /> developed DYNFLOW Groundwater Model for Eastern San Joaquin County.
<br /> The estimated and projected water demands presented are based on the following
<br /> assumptions:
<br /> 1. Drastic changes in cropping patterns will not change drastically.
<br /> 2. Applied water demands include evapotranspiration, system losses, tailwater drainage,
<br /> and percolation to groundwater.
<br /> 3. Applied water demands do not include conveyance losses or off-farm demands. The
<br /> applied water demand is the information necessary for the groundwater model, which
<br /> also takes into account the differences in consumptive use for each parcel of land.
<br /> Urban areas have different consumptive use than agricultural areas, and consumptive
<br /> use also varies between different types of crops. Therefore, the applied water demand
<br /> will usually be less than the diversion amounts maintained by each district.
<br /> The decrease of 132,000 of of agricultural water use can be compared to an increase in urban
<br /> water use of 146,000 af. In terms of net demand, this is not a significant change. This similarity
<br /> in demand is due to an approximate one-to-one conversion rate between urban and agricultural
<br /> use for each acre. The usage rates for agricultural and urban water use are similar, with urban
<br /> water use slightly higher per acre. Most land around urban areas is currently farmed; thus, in
<br /> order for the urban areas to expand, agricultural land would be converted at an approximate
<br /> one-to-one ratio. Because each acre of new urban land results in 1 less acre of agricultural
<br /> land, and the water use figures are similar, the water demands are projected to remain
<br /> essentially constant throughout the planning period.
<br /> Northeastern San Joaquin County Section 2
<br /> Groundwater Banking Authority 75 Hydrogeology
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