2008-11-03_REVISION - M1999098 - Laserfiche WebLink

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Ms. Joanna Williams RE: WW Farms Expansion SWSP Request April 22, 2008 Page 3 of S calibrated coefficients for the high altitude .locations.. Locally calibrated coefficients for the plains 'areas (east . of the . foothills) were developed through calibration with the ASCE Standardized Equation, due to the lack of lysimeter data in this area. The "Upper -Plains" region includes Greeley, Fort Collins and Fort Lupton because they. are all similar in location and elevation. The "Lower Plains" region includes .Sterling because it.has a noticeably lower, elevation and different location. In general, the ASCE Standardized method may produce a greater seasonal. potential consumptive use. in certain locations with certain. crops (i.e. with alfalfa; grass pasture, and small grains). In other areas, the modified Blaney-Criddle equation with TR-21 coefficients may produce higher potential consumptive use (i.e. dry beans, sugar beets, and corn. grain). We. assumed 50% of the return flows- were surface and 50% subsurface. We used a Glover, stream- depletion analysis, the Alluvial Water Accounting System (AWAS) model," "and the. parameters summarized in the table below. The subsurface return flows were lagged back to. the Cache la Poudre River. Parameter Value Distance from property to river 4,210 ft Distance from river to impermeable boundary 11,440 ft Transmissivi 180,000 d/ft Specific Yield 0.2. Table 3 summarizes the consumptive use analysis for the 2.5 Whitney Ditch shares that were used on Mr. Orr's property. The total net consumptive use available for the dry-up of this 24 acre property is 37.3 acre-feet. OPERATION OF THE PLAN During,the first year of active mining there will be approximately 19.6 acre-feet of depletions of which 17.69 acre-feet are lagged and owed to the .stream system. Dewatering will likely occur to cover these initial depletions. However, to show that we have enough water to cover a worst- case scenario, we are not showing that credit. Table 4 shows that the 2.5 shares of.the Whitney Ditch more than cover the depletions from April to September. However, return flow obligations accrue from October to March and are owed to the stream system along with the-site lagged depletions. These depletions will occur during the winter when the calling rights are downstream. Therefore, the excess South Platte Replacement water from the CoSSP will cover the depletions as shown. on Table 4. We propose to use any combination of the following South Platte Replacement sources to cover the winter depletions and they include but are not limited to: • 295 acre-feet of effluent from the City of Westminster in the form of a perpetual lease, with 19.94 acre-feet dedicated to the Teti Pit augmentation plan (Table 4 shows the remaining balance). River Resource ' Amendment to Permit M1999098 112C Page G14 of, G37