HYDRO22002

• Permit No: M1997058
• IBM Index Class Name: Hydrology
• Doc Date: 3/4/2004
• Doc Name: Substitute Water Supply Plan Approval
• From: OSE
• To: Leaf Engineering
• Media Type: D
• Archive: No

C~
STATE OF COLORADO
OFFICE Of THE STATE ENGINEER
Division of Water Resources
Department of Natural Resources
1313 Sherman Street, Room 818
Denver, Colorado 80203 March 1, 2004
Phone [phone]
FAX [phone]
www.wa[ersta[e.co.us
Mr. Forrest Leaf
Leaf Engineering
2607 W. 10'" Street
Greeley, CO 80634
RECEtVE® ~6°~~`°~.~
yeO* i
MAR 0 42004 ,~~.
'~ /896 ~
Division ~f Minerals and Geology
Bill Owens
Governor
Greg E. VJalcher
ExecuBve Direttor
Hal D. Simpson, pE.
SGre Engineer
Re: Baseline Resource Aggregate Mine, Substitute Water Supply Plan
DMG File No. M-97-058
Section 36, T1 N, R67W, 6t" P.M., Adams County
Water Division 1, Water District 2
Dear Mr. Leaf:
We have received your letter of December 16, 2003, requesting renewal and amendment
of the above referenced substitute water supply plan (SWSP) to cover depletions caused by an
existing gravel mining operation. The required fee of $217.00 for the renewal of this substitute
supply plan has been submitted. The original supply plan was approved on May 21, 2001.
The Baseline Resources mining area is split into two adjacent sites. An existing slurry
wall encompasses the East site, while the West site is located outside of the wall. According to
the plan it is anticipated that 500,000 tons of material will be mined from the East site during the
term of this SWSP. Since only aggregate from within the slurry wall will be mined, replacement of
water retained in the mined product is not required.
The ground water exposed at this site consists of 0.96 acres of dewatering trenches, and
2.7 acres of settling ponds. The annual depletion due to evaporation from the 3.66 acres,
exposed after December 31, 1980, is 10.75 acre-feet. The depletions from evaporation were
lagged to the stream system based on a SDF of 76 days (the centroid of the parcel surrounding
the slurry wall).
An alluvial well has been constructed to provide water for concrete batching and dust
suppression. This well was constructed under permit no. 57068-F and is located outside the
boundaries of the slurry wall. Total estimated annual consumptive use for the alluvial well is 6.1
acre-feet for concrete batching and 3.3 acre-feet for dust control. The water withdrawn from the
alluvial well is considered 100% consumptive.
The construction of the slurry wall affects the timing of the lagged impacts on the South
Platter River, from the alluvial well. The applicant has prepared a numeric model to account for
this affect. According to the model, the depletions attributed to the Batch Plant production well
were estimated to increase from a Stream Depletions Factor (SDF) of 68 days to 176 days, due to
the increased flow path.