2015-04-20_HYDROLOGY - M1999005 - Laserfiche WebLink

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Mr. Nathan D. Phelps April 20, 2015 Page 2 of 5 Regulations for the protection of water resources. The April 30, 2010 letter from DRMS requires that you provide information to DRMS to demonstrate you can replace long term injurious stream depletions that result from mining related exposure of groundwater. The DRMS letter identified four approaches to satisfy this requirement. In accordance with approach nos. 1 and 3, you have indicated that a bond has been obtained for $175,334 through the DRMS to assure that depletions from groundwater evaporation do not occur in the unforeseen event, or events, that would lead to the abandonment of the North River Pit. DEPLETIONS Since no mining is planned during 2015, pond evaporation will be the only water demand at the site. The total water surface area for the two ponds at the site is presently 8.06 acres (Figure 2). For the purpose of this SWSP, you determined the evaporation from the 8.06 acres to be 32.40 acre -feet, based on a net annual evaporation of 4.02 feet from the Lower Arkansas Water Management Association's ( "LAWMA ") decree in Case No. 2002CW181. The gravel pit is located about 300 feet north of the Arkansas River. A Glover analysis was used to estimate the timing of stream depletions. A stream depletion factor of 7.5 days was taken from "Stream Depletion Factors, Arkansas River Valley, Southeastern Colorado" by C.T. Jenkins and 0. James Taylor (USGS OFR 72 -192). Steady state conditions were assumed and the monthly water uses estimates from Table 1 (attached) were used. Note this is the last plan approval that a lagging analysis utilizing Stream Depletion Factors obtained from USGS Publication 72 -192 will be allowed without justification of the method; otherwise, a lagging analysis which incorporate methods that are physically relevant to this site (ie a Glover analysis with no flow boundary) should be utilized in all future plan renewals. REPLACMENT All -Rite leased fully consumable water from AGUA and will use this leased water as the source of replacement water through September 25, 2015. A copy of the current lease for up to 32.4 acre -feet for the period ending September 25, 2015 was provided with the SWSP request and is attached to this letter. All -Rite will renew the lease with AGUA to cover the period ending March 31, 2016. A copy of the new lease with AGUA must be provided to this office by September 25, 2015 in order for this SWSP to remain valid. ACCOUNTING The attached Table 2 is the monthly accounting form that will be used for determining water use and stream depletions. All -Rite will submit the monthly pit area to AGUA, which will then submit the monthly water accounting to the Division Engineer. oF�Oto 1313 Sherman Street, Room 821, Denver, CO 80203 P 303.866.3581 F 303.866.3589 www.water.state.co.us I y� : o'I 1876 �`i