PERMFILE128924

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 6/2/2006
• Section_Exhibit Name: Exhibit 52 Water Augmentation Plan
• Media Type: D
• Archive: No

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Creek approximately 1000 Peet upstream from the confluence of
Dry Fork and Minnesota Creek; and
c. Lick Creak Gauge, which Applicant installed
and maintains: located on Lick Creek approximately 3500 Peet .
above the confluence of Lick Creek and the East Fork of
Minnesota Creek.
13. The contribution factors were developed from
the historical stream flow conditions on Minnesota Creek and
the potentially affected tributaries, Dry Fork and Lick
Creek. Average monthly flows for Minnesota Creek, Dry Fork,
and Lick Creek were adjusted for storage, releases,
transbasin diversions, and all other manmade alterations, to
arrive at figures representing average monthly virgin stream
flow for each stream. These figures for Dry Fork and Lick .
Creek were then divided by the Minnesota Creek average
monthly flows to arrive at the monthly contribution factors
for each creek, representing the percentage contribution, on
average, of that creek to the flow of Minnesota Creek at the
Minnesota Crdek Gauge.
14.' The above-described contribution factors are
utilized, along with measured stream flow, changes in
storage, imported water, and diversion, and estimated
upstream return flows, to determine the expected stream flow
of Minnesota Creek at the identified gauge during retreat
mining operations. The expected flow at the Minnesota Creek
Gauge is calculated with one of the two equations designated
for that purpose in Exhibit C, depending upon whether retreat
mining is occurring only under Dry Fork or also under Lick
Creek. The measured flow at the Minnesota Creek gauge and
the Dry Fork gauge, and when relevant (i.e., when retreat
mining is occurring beneath both Dry Fork and Lick Creek) at
the Lick Creek gauge, is adjusted for known manmade changes
(reservoir storage, upstream diversions, imported water, and
return flows), and the expected virgin contribution of Dry
Fork, or of Dry Fork and Lick Creek, as appropriate, is
factored into the equation through use of the contribution
facts. The number resulting from performance of this
calculation is in effect the reconstructed virgin flow of
Minnesota Creek at the Minnesota Creek Gauge; i.e., the flow
that would be measured by the Minnesota Creek Gauge if the
creek were unaffected by mining activity or other manmade
controls or alterations.
15. The expected flows of Dry Fork and/or Lick Creek
are calculated with the equations designated for that
purpose in Exhibit C. The expected flow in Minnesota Creek,
calculated as described above, is multiplied by the appro-.
priate monthly contribution factor for Dry Fork or Lick
Creek. The resulting value(s) represent the flow that would
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