2017-03-02_HYDROLOGY - M1977436 - Laserfiche WebLink

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youth Platte Combined Replacement Plan Page 5 of 19 March 1, 2017 Depletions The depletions resulting from evaporation, water lost in mined product, dust control and concrete batching at each site are shown in Table C below: Table C - DeDletion Summary (all amounts in acre-feet) ° Evaporation is replaced by the City of Longmont under their augmentation plan decreed in water court case no. 09CW271. e Lagged Dewatering Depletions, as shown in the table, are from past dewatering operations that have ceased but continue to impact the stream system. `This SWSP request assumed 15.0 acres of ground water would be exposed for the entire plan period. d So long as the pit is continuously dewatered, the water returned to the stream system is considered to be adequate to offset depletions attributable to the dewatering. A stream depletion model using either the Glover method, or Stream Depletion Factor (SDF) method was used to calculate the lagged depletions to the river. The Glover method uses four aquifer input parameters for each site as follows: 1) X - distance (ft) from centroid of exposed ground water to river, 2) W - distance (ft) from the aquifer boundary through the well to the river channel, 3) T - transmissivity of the alluvial aquifer (in gallons per day per foot) between the well and the river, and 4) S - specific yield (0.2 was used for all wells). The parameters used in the model for each site are listed in Table D below. Table D - Aquifer Characteristics Site Name T (gal/day/ft) X (ft) W (ft) OF (days) Jeronimus Pit 100,000 1,600 Lagged Hazeltine Pit 100,000 1,200 Water Lost in Dust Concrete - Lagged Dewatering Total Site Name Evaporation Mined Product Control Batching Total Depletions Depletions Lagged 7,400 - Distel Pit 50,000 700 5,300 - Tull Pit 50,000 Impacting Depletions W.W. Farms Pit 120,000 900 8,750 - F -Street Pit 120,000 2,600 the Rive Jeronimus Pit 15.00 0 0 0 15.00 16.06 0 16.06 Hazeltine Pit 40.18` 0 1.98 0 42.16 41.43 Od 41.43 Brighton Pit 13.67 0 0 0 13.67 15.59 3.40 18.99 Tucson South Pit 5.47 0 0 0 5.47 5.47 0 5.47 Wattenberg Pit 14.65 54.48 (1,851,000 tons) 1.98 0 71.10 70.73 Od 70.73 Platte Valley Pit 200.43 0 10.61 7.51 218.5 218.30 0 218.30 Distel Pit 0& 0 1.54 3.31 4.85 4.47 0.23 4.70 Tull Pit 2.58 20.63 (701,000 tons) 0.99 0 24.20 14.58 Od 14.58 W.W. Farms Pit 100.44 0 0.99 2.30 103.73 108.08 0 108.08 F -Street Pit 1 71.79 1 0 0 0 71.79 71.79 0 71.79 Total I-- -- -- -- 570.47 1 570.13 ° Evaporation is replaced by the City of Longmont under their augmentation plan decreed in water court case no. 09CW271. e Lagged Dewatering Depletions, as shown in the table, are from past dewatering operations that have ceased but continue to impact the stream system. `This SWSP request assumed 15.0 acres of ground water would be exposed for the entire plan period. d So long as the pit is continuously dewatered, the water returned to the stream system is considered to be adequate to offset depletions attributable to the dewatering. A stream depletion model using either the Glover method, or Stream Depletion Factor (SDF) method was used to calculate the lagged depletions to the river. The Glover method uses four aquifer input parameters for each site as follows: 1) X - distance (ft) from centroid of exposed ground water to river, 2) W - distance (ft) from the aquifer boundary through the well to the river channel, 3) T - transmissivity of the alluvial aquifer (in gallons per day per foot) between the well and the river, and 4) S - specific yield (0.2 was used for all wells). The parameters used in the model for each site are listed in Table D below. Table D - Aquifer Characteristics Site Name T (gal/day/ft) X (ft) W (ft) OF (days) Jeronimus Pit 100,000 1,600 23,000 - Hazeltine Pit 100,000 1,200 23,000 - Brighton Pit - - - 10 Tucson South Pit 75,000 1,600 4,600 - Wattenberg Pit 80,000 1,200 5,500 - Platte Valley Pit 150,000 1,400 7,400 - Distel Pit 50,000 700 5,300 - Tull Pit 50,000 4,900 9,300 W.W. Farms Pit 120,000 900 8,750 - F -Street Pit 120,000 2,600 5,000 - Office of the State Engineer 1313 Sherman Street, Room 821, Denver, CO 80203 P 303.866,3581 www. water. state.co. us of. Co y � + 't4E J876 41