HYDRO28762

• Permit No: M1999002
• IBM Index Class Name: Hydrology
• Doc Date: 7/26/1999
• Doc Name: VIC
• From: RIO BLANCO CNTY
• To: RIO BLANUS ENVIRONMENTAL PROTECTION AGENCY
• Media Type: D
• Archive: No

6
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(b) which is not an exempt aquifer.
In this area aquifers are located in the Uinta an<i Green
River Formations and in the alluvial gravels at the surface of
stream valley bottoms. The principal aquifer systems ;Figure 2)
includes two bedrock aquifers separated by a leaky semi.-confining
layer known as the Mahogany Zone. These two aquifers zire
commonly referred to as the "Upper Aquifer," which lie;; above the
Mahogany Zone, and the "Lower Aquifer," which lies below the ~M}t M~~~,^
Mahogany Zone. The chemical quality of groundwater vax•ies within a~~~ ~~ ,..
and between the aquifers. Ground water from the Lower and Upper Nsa~~~e~:
Aquifers generally does not meet public drinking water standards,+~,,,.•
although ground water from the Uinta portion of the Upper Aquifer
is frequently used for livestock watering and also supper-i,e~5"~3ome ~1~~~~?
local ranches. There are no ranch wells in the AOR. t Data ~ / c1`
indicates there are most likely no USDWs below the bade of` the
Uinta (approximately 675 feet from surface) at the site of this t
lease, and represents a very generalized view of the aquifer
system throughout the Basin.
Springs and Wells: There are two (2) springs within three
(3) miles of the Piceance Site. The nearest is less than 1.75
miles south of the Piceance Site at the confluence of Ryan Gulch
and Piceance Creek. This spring is hydrologically up gradient of
the Piceance Site. The other spring is about 2.5 miles northeast S ~S 1
of the Piceance Site, near the Square S Ranch. This spring is ~ ,~{cS
hydrologically downgradient from the Piceance Site. Springs and ,,~
seeps at the Piceance Site shall be monitored for flow :rate and ~h~`
water quality. A spring season baseline and seep survey/ shall be x
conducted during the peak flow period in late spring of 1999. A
second spring and seep survey shall be conducted prior to
commercial operations in the fall of 1999 to document low flow
conditions.
A single water well, well P73-4 (USGS identification number ,„,,.7 ~`~)~
395630108170600) , exists in the area. This well is locz~ted less F,.~"''~~'
than one (1) mile southeast of the Piceance Site. It ways P;y~,rvi'
installed in the alluvium of Piceance Creek for use as a.
sampling/monitoring well, but its current status is unknown.
According to the Colorado Department of Public Health and
Environment and the Colorado Department of Natural Resources
State Engineer's Office, the only designated public Water supply
system within a 10-mile radius of the Piceance Site is located
approximately 10 miles west of the Piceance Site. It is reported
to .be inactive. There are also three (3) BLM water wells within
a 10-mile radius of the Piceance Site: these are not designated
public water supply wells.