_PERMIT FILE - M1995035 ‎(10)‎

• Permit No: M1995035
• IBM Index Class Name: Permit File
• Section_Exhibit Name: EXHIBIT G WATER INFORMATION
• Media Type: D
• Archive: No

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Groundwater
Test holes in the deposit and groundwater lakes north of the Wellington Downs site indicate the
alluvial groundwater aquifer is encountered at average depth of 10 feet below the surface. In order
to mine the entire deposit dry, it will be necessary for Connell to dewater.
Connell has located two discharge points. When excavating at the south end of the property they
will discharge into Mallard Creek, south of County Road 4 36. While excavating on the north end
of the property they will pump water into a culvert which discharges into the Box Elder Ditch, east
of 1-25. These proposed discharge points are located in Exhibit C.
Dewatering sumps or trenches will be dug in the pit bottom to capture the groundwater flow and
reduce the amount of suspended solids discharged. Connell will obtain the appropriate discharge
permits from the Colorado Department of Health prior to any dewatering activity.
The proposed reservoir will be created by placing a compacted overburden/clay liner along the
shorelines of the excavated pits (see Exhibit F). Placement of the compacted loner along the
shoreline will eliminate groundwater inflow into the pit. The pit will be mined doom to bedrock and,
therefore there will be no infiltration through the bottom of the pit. The reservoir will be exempt
from regulations of Senate Bill 120 since there will be no groundwater depletions.
The Water Court and the SEO have set a standard for the construction of gravel pit reservoirs. The
acceptable limit of seepage is 1 gpm per 100 liner feet of reservoir shoreline. The Wellington
Downs reservoir will have approximately 7360 feet in perimeter and consequently will have an
allowable 73.60 gpm seepage. This equates to 118.72 acre-feet of seepage annually.
After the construction of the reservoir liner, the pit will be examined by the SEO's for seepage. If
the pit on not within acceptable ranges, localized reconstruction of problem areas will be done.
Water Use
The quantities of water used is expected to remain the same as Connell's present operation. Water
use at the site will include evaporation from wash ponds, water retained in the material removed
from the site, water used for dust control for haul roads and stockpiles.
Evaporation from the site during mining will include water exposed due to the dewatering operation
and water pumped from the pit to settling ponds used for the washing operation. Approximately .3
acres of water will be exposed in the dewatering trenches and ponds.
The annual evaporation is 39 inches at the Wellington Downs site. The precipitation at the mine site
is estimated to be the same as that found at the nearest weather station which is located in Fort
Collins. The annual mean precipitation here is 14.7 inches.
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