_REPORT - M1995035 ‎(7)‎

• Permit No: M1995035
• IBM Index Class Name: Report
• Doc Name: STORMWATER MANAGEMENT PLAN WELLINGTON DOWNS PIT
• Permit Index Doc Type: ANNUAL FEE / REPORT
• Media Type: D
• Archive: No

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Effective precipitation was determined in order to compute the net surface water evaporation.
Effective precipitation was computed as 70% of the total precipitation (10.29). Effective
precipitation was then subtracted from the gross evaporation to obtain the net evaporation.
An adjustment is also made for the months of January and February when the water surface is
typically frozen. The net annual evaporation from surface water at the subject site is 2.26 ft (27.1
inches). Consequently the net annual evaporation during mining Gom 0.3 acres of surface water will
be .67 acre-feet.
The most material Connell will mine in a year is projected at 250,000 tons. Assuming a 4
moisture content by weight, this would equate to about 7.35 acre-feet annually.
Water also includes water applied for dust control. The quantity of water needed for dust control
during mining should be about .8 acre-feet per annually.
Table G-1 summarizes annual consumptive.
Table G-1 Annual Consumptive Use (acre-ft)
Evaporation .67
Moisture Retained in Material 7.35
Dust Control .8
TOTAL: 8.82
Augmentation
In order to prevent injury of senior water rights along the Cache La Poudre River, augmentation of
the out of priority depletions at the site is required. During mining of the Wellington Downs site it
is estimated that approximately 8.82 acre-feet of groundwater will be consumed each year. The
Wellington Downs operation is not expected to exceed the current water uses at the Stute Pit because
it will be a similaz operation.
The lease agreement between Connell and Grant entitles Cottrell to use the water rights of Grant to
offset the depletion from the mining operation. Grant has 2 1 /2 shares of the Box Elder Ditch water.
One share is valued at about 93.7 acre-feet/yeaz. Therefore, their is more than enough ditch water
to off-set the depletion from the mining operation.
Connell will obtain a temporary Substitute Water Supply Plan from the State Engineer's Office
(SEO) allow them to consume water during the mining phase of the operation (as well as a Wel]
Permit).
As stated eazlier the final reclamation of the site is a water storage reservoir. The reservoir will be
sealed from the surrounding alluvial aquifer to prevent groundwater infiltration. Consequently there
will be no long term augmentation responsibilities. The Lessor shall be responsible operation of the
reservoir and for any leasing of water storage rights.