2019-04-24_HYDROLOGY - M2006003

• Permit No: M2006003
• IBM Index Class Name: Hydrology
• Doc Date: 4/24/2019
• Doc Name: Substitute Water Supply Plan
• From: DWR
• To: Civil Resources, LLC
• Email Name: ECS
• Email Name: MAC
• Media Type: D
• Archive: No

Mr. Andy Rodriguez, P.E.
Beltway's Brighton Combined SWSP
April 24, 2019
Page 2 of 6
reservoirs from any source, including precipitation and groundwater inflows, shall be removed
by the applicant. The water may be removed from within the lined area and returned to the
stream system through surface flow or groundwater recharge without need for replacement,
so long as the operator does not put the water to beneficial use.
The Applicant holds through the Division of Mining Reclamation and Safety bonds in the
amounts of $974,000.00 for the Parker-Dersham Pit and $711,750.00 for the Baseline Pit
which can be used to line the respective pits in the unforeseen event, or events, which would
lead to the abandonment of the Pits.
Depletions
The Applicant has stopped mining at the Parker-Dersham and Baseline Pit sites are fully
reclaimed and awaiting germination of planted seed. The southwest corner of the
Parker-Dersham Pit site and the Dersham property has been reclaimed and taken over by the
City of Aurora, and the remaining portion of the Parker-Dersham Pit site located in the
northwest corner has been backfilled.
The depletions from past mining operation were lagged to the South Platte River using the
SDF method. The construction of the slurry wall at the Baseline Resource site affects the
timing of the lagged impacts on the South Platte River. The applicant previously prepared a
numeric model to account for this effect. According to the model, the SDF for the
evaporative loss was estimated to be 205 days and the SDF for the plant well is estimated to
be 176 days. The lagged depletions from the SDF modeling show 85 % of the depletion have
been replaced and the remaining 15% of lagged depletions (105.88 acre-feet) occur until
2080. However when using IDS AWAS stream depletion modeling to determine the lagged
depletions using transmissivity (T) of 150,000 gallons per day per foot, specific yield (SY) of
0.15, distance from the South Platte River to the edge of the alluvium (W) of 5,065 ft and
distance from the centroid of the exposed surface water areas to the South Platte River (X) of
2,020 ft, showed lagged depletions to the South Platte River ended in 2018. Therefore we
will accept the Applicant's proposal to replace the total remaining lagged depletions from the
SDF method of 105.88 acre-feet in the next three years as shown in Table 1 below and column
1 of attached Table 3.
Table 1. Replacement Table
Replacements
The proposed source of replacement for this pit is nontributary groundwater pumped from an
existing Laramie -Fox Hills aquifer well and fully consumable effluent leased from the City of
Aurora.
Jan
Feb
Mar
Apr
May
June
Jul
Aug
Sept
Oct
Nov
Dec
Total
2019
2.68
2.42
2.28
2.33
2.53
2.81
3.17
3.22
3.59
3.59
3.43
3.15
35.2
2020
2.68
2.42
2.28
2.33
2.53
2.81
3.17
3.22
3.59
3.59
3.43
3.15
35.2
2021
2.68
2.42
2.28
2.33
2.53
2.81
3.17
3.22
3.59
3.59
3.43
3.15
35.2
Replacements
The proposed source of replacement for this pit is nontributary groundwater pumped from an
existing Laramie -Fox Hills aquifer well and fully consumable effluent leased from the City of
Aurora.