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Peter Wayland <br />January 19, 2006 <br />Page 2 <br />prior to January 1, 1981. Depletions from the mining of this proposed operation will accrue to <br />St. Vrain Creek. <br />You have provided a monthly breakdown of the maximum year annual depletions <br />totaling 2.89 acre-feet of evaporative loss from a maximum of 1.19 acres of groundwater <br />exposed after January 1, 1981, 1.2 acre-feet of water used and consumed for dust control, and <br />10.92 acre-feet of water lost with 371,000 tons of mined product. <br />The mining operation is located greater than 100 feet from St. Vrain Creek. As a result, a <br />stream depletion analysis using Glover techniques has been performed as a means to assess the <br />lagged depletions to St. Vrain Creek resulting from the proposed operation of the Nelson Mining <br />Resource Gravel Pit. The schedule for replacement of depletions takes into full account all annual <br />depletions accounting for the lagged effect over 10 years and normalized according those monthly <br />percentages. As a result, full replacement of depletions to St. Vrain Creek are made on a monthly <br />basis. <br />Replacements <br />The proposed source of replacement for this pit is fully consumable wastewater <br />treatment plant effluent or reservoir releases from a lease with the City of Longmont. The City <br />of Longmont wastewater treatment plant is located approximately 10.5 miles upstream of this <br />new mining operation. A 0.25 percent per mile transit loss (2.625 percent overall loss) has <br />been accounted for in the replacements. The monthly depletions and replacement <br />requirements are found on the attached table. <br />Conditions of Approval <br />As required by Section 8 of Senate Bill 89-120, this substitute water supply plan has been <br />provided to an outside consultant for review. The consultant has recommended approval of the <br />plan by way of a draft of this letter. Based upon statutory requirements and the recommendations <br />of the consultant, I hereby approve the proposed substitute water supply plan in accordance with <br />Section §37-90-137(11), C.R.S., subject to the following conditions: <br />This SWSP shall be valid for the period of January 1, 2006 through December 31, 2007, <br />unless otherwise revoked, modified, or superceded by decree. If this plan will not be <br />made absolute by a water court action by the plan's expiration date, a renewal request <br />must be submitted to this office with the statutory fee by November 1, 2007. <br />2. The losses associated with this mining operation must not exceed a total of 15.02 acre- <br />feet annually for the duration of this plan approval. These losses include 2.89 acre-feet <br />of evaporation from the proposed exposure of up to 1.19 acres of groundwater, 1.2 acre- <br />feet of water used for dust suppression and 10.92 acre-feet of water lost in 371,000 tons <br />of mined aggregate. Should the tosses associated with the mining operation exceed <br />15.02 acre-feet annually, prior to the expiration date of this plan, an amendment will need <br />to be filed with this office. <br />3. A copy of the lease with the City of Longmont must be submitted to the State Engineer's <br />Office prior to commencing mining at the site. <br />