2024-11-22_REVISION - M1999120 ‎(4)‎

• Permit No: M1999120
• IBM Index Class Name: Revision
• Doc Date: 11/22/2024
• Doc Name: Request For Amendment To Permit
• From: L.G Everist, Incorporated
• To: DRMS
• Type & Sequence: AM3
• Email Name: NCG
• Email Name: JLE
• Email Name: EL1
• Media Type: D
• Archive: No

EXHIBIT G WATER INFORMATION
Introduction
The amended Fort Lupton Sand and Gravel Mine is located in
parts of Sections 19, 30 and 31; Township 2 North, Range 66 West,
and Sections 24, 25 and 36, Township 2 North, Range 67 West of the
6th P.M., Weld County, Colorado. The site is approximately one
mile northwest of the City of Fort Lupton, Colorado. MAP EXHIBIT B-1
shows the layout of the permit area and amendment portions in
relation to surrounding areas.
For the existing permit area, ground water studies done
during the 2004 amendment explained the impacts expected due to
liners being placed in the South Platte alluvial valley. In
general, the ditches, river and streams lying across the site, or
on either side will limit mounding or shadowing around the site.
Impacts from other permitted mining operations that have installed
liners south of WCR 18 and along WCR 25 between the new parcels
will also contribute to the change in historic groundwater levels
that LGE has no control of, nor can correct if needed.
Mitigation Trigger
Starting in 2004 L.G. Everist, Inc. began to collect ground
water elevations on areas around the mine. The period from May
2004 to August 2006 was used as the baseline for triggering
mitigation actions. Since late 2006 outside influences not caused
by LGE continue to act on the groundwater levels that have/are
changing the levels and impacting our trigger point. There has
been an increased gravel mining presence north of the Fort Lupton
Sand and Gravel Mine that has dewatering operations west of
monitoring wells 9 & 10. Impacts are also beginning to be seen to
ground water levels in the Parker Phases on the south due to the
new mining operation and liners installed south of WCR 14 .5.
Another outside influence is the reduction/elimination of
groundwater wells pumping, mandated by DWR, from the South Platte
River alluvial aquifer. Since 2012 the water table has stabilized
from 2.5 to 3 feet higher than the DWR pre-pumping ban and the new
normal levels are reflected in the data LGE has collected since
then.
During our investigations, we determined the causes were due
to system-wide environmental factors out of our control.
Realistically the mitigation trigger number should be based on a
plus or minus 5 foot over the high and low range of the baseline.
LGE has not had a problem with mounding being a problem where the
slurry walls are in close proximity to a flowing water body as
discussed in the January 2005 Wright Water Engineers report. For
example, there is flowing water along the east side with the South
Platte River & Lupton Bottoms Ditch east lateral; on the west side
with the Lupton Bottoms Ditch and Little Dry Creek/Slate Ditch,
and along the south side of the Blue Ribbon Parcel next to the
PVIC irrigation return flow ditch. However, we have found that
activities such as: damming of the Little Dry Creek/Slate ditch by
beavers, and local farmers flood irrigating and dumping their
L.G.Everist, Inc. M-1999-120
Ft.Lupton Sand and Gravel November,2024
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