2015-07-09_HYDROLOGY - M1977439 - Laserfiche WebLink

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Upper Poudre Combined SWSP Page 4 of 11 June 26, 2015 alluvial aquifer boundary condition: the distance (X) from the centroid of the exposed ground water surface to the river; the width (W) of the aquifer on the side of the river where the pit is located; the transmissivity (T); and the specific yield (S). The Glover parameters used for each site are shown in Table C below. Table C - Glover Parameters Site Name X (ft) W (ft) T (gpd/ft) S Home Office Pit 1,000 6,500 160,000 0.2 Overland Ponds Pit 2,000 3,000 160,000 0.2 North Taft Hill Expansion Site 1,600 2,900 1 160,000 1 0.2 The estimated consumptive use and lagged stream depletions due to past and projected evaporation and operational losses at the subject sites will total 89.74 acre-feet for this plan period as shown on the attached Table 5. Lagged depletions due to past evaporation and operations at the two Treiber Lakes and three Lamb Lakes are replaced under the Partners Combined SWSP. Dewatering The Home Office Pit has not had any active dewatering since MMM took over the site in 2012. The North Taft Hill Expansion Site will be continuously dewatered throughout this plan period. For the purposes of this SWSP, you have assumed the site to be in a steady state condition where dewatering accretions equal the lagged depletions. All dewatering from the North Taft Hill Expansion Site will be pumped to the unlined 30.9 -acre pre -81 pond just south of the site. The pond has the ability to overflow directly to the Cache la Poudre River. A totalizing flow meter has been installed on the pump and monthly meter readings are reported on the submitted accounting for this plan. All water spilled from the pond is also metered. As long as the dewatering operations are constant the North Taft Hill Expansion Site may continue to operate assuming steady state conditions. Once dewatering ceases or is reduced in its flow, lagged depletions will impact the river. At least three years prior to a modification in dewatering operations, the Applicant must provide a plan showing how lagged post -pumping depletions will be replaced in the proper time and amount. The post pumping analysis shall use the meter data from the dewatering totalizing flow meter. All cells of the Overland Ponds Site were fully lined by September 2014, therefore dewatering at the site has ceased. All dewatering water pumped from the Overland Ponds Site was delivered to an unlined pond just north of the site (Treiber Pond B) where it was allowed to infiltrate into the alluvial aquifer. A totalizing flow meter was installed on the pump and monthly meter readings were included in the submitted accounting for this plan. AWAS was used to lag the resulting recharge accretions from the unlined pond to the Cache la Poudre River. The following parameters were used in the model with the alluvial aquifer boundary condition: a distance (X) from the centroid of the pond to the river of 700 feet; a width (W) of the aquifer of 3,000 feet; a transmissivity (T) of 160,000 gallons per day per foot; and a specific yield (S) of 0.2. The monthly lagged dewatering depletions from the Overland Pond site are calculated and compared to the monthly lagged dewatering recharge accretions from Treiber Pond B. Any shortages must be replaced as depletions under this SWSP. Replacements Replacements for this combined plan will come from credits associated with 13.175 out of 15.175 shares owned by MMM in the Taylor Et Gill Ditch. In the event that the yield from the 13.175 shares is less than projected, MMM may supplement their replacement supplies with other sources, subject to the Division Engineer's approval.