2022-06-29_HYDROLOGY - M2015030

• Permit No: M2015030
• IBM Index Class Name: Hydrology
• Doc Date: 6/29/2022
• Doc Name: Substitute Water Supply Plan
• From: DWR
• To: DRMS
• Email Name: ECS
• Email Name: MAC
• Media Type: D
• Archive: No

Chavers Mining Resources Substitute Water Supply Plan 2022 Page 3 of 8
June 27, 2022
Dust Control
The estimated water used for dust suppression per year total 1.25 acre-feet per year or 0.52 acre-feet
for the period of August 1, 2022 through December 31, 2022, as shown in Table 3, column 3.
Mined Product
In addition to the evaporation, water is lost with the mined product removed from the mine site. The
Applicant projects that they will produce 700,000 tons of gravel for each year. Gravel mined will be in a
dewatered state and will be washed, therefore the groundwater lost with the mined product during this
period is estimated at 4 percent by weight. The water lost with the mined product is projected to total
20.61 acre-feet per year or 8.21 acre-feet for the period of August 1, 2022 through December 31,
2022, as shown in Table 3, column 2.
Concrete Production
As mentioned above, the water used for concrete production will be provided by the alluvial well (permit
no. 80120-F). Assuming 30 gallons of water/cubic yard and 154,000 cubic yards of concrete production,
the estimated water used for concrete production is 14.18 acre-feet per year or 6.28 for the period of
August 1, 2022 through December 31, 2022, as shown in Table 3, columns 4 and 5.
Total Consumptive Use: Evaporative and Operational Depletions
Annual depletions include evaporative losses of 7.93 acre-feet per year for the pump basin and
dewatering trench, evaporative losses of 8.12 acre-feet per year for the wash ponds, 20.61 acre-feet of
water lost with the mined product, 1.25 acre-feet of water used for dust control, and 14.18 acre-feet of
water used for concrete production.
Depletions for the period of August 1, 2022 through December 31, 2022 include evaporative losses of 3.0
acre-feet per year for the pump basin and dewatering trench, evaporative losses of 3.09 acre-feet per
year for the wash ponds, 8.21 acre-feet of water lost with the mined product, 0.52 acre-feet of water
used for dust control, and 6.28 acre-feet of water used for concrete production.
The total annual consumptive use at this site is 52.09 acre-feet per year and the total consumptive
use is 21.1 acre-feet per year for the period of August 1, 2022 through December 31, 2022.
Lagged Depletions
The IDS AWAS stream depletion model was used to determine the lagged depletions from evaporation,
operational losses, and the alluvial well to the South Platte River. The model parameters used are shown
in Table A below.
Table A. IDS AWAS Model Parameters
Boundary Distance from Transmissivity Specific Distance from
Well Name Condition boundary to stream (gpd/ft) Yield well to stream
ft ft
A ,repate Mining Alluvial Aquifer 7,500 85,000 0.2 575
Aggregate Processing Alluvial Aquifer 7,500 85,000 0.2 1,275
Concrete Production Alluvial Aquifer 7,500 85,000 0.2 1,045
Annual lagged depletions are as follows: 28.43 acre-feet associated with the evaporation from the pump
basin and dewatering trench and mined aggregate (row 2, Table A above), 9.04 acre-feet associated with
the evaporation from the wash pond and dust control (row 3, Table A above), and 13.73 acre-feet