2012-11-28_HYDROLOGY - M1998013 - Laserfiche WebLink

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Mr. Andy Rodriguez, P.E Page 3 of 6 Shores SWSP November 26, 2012 acre -feet for this plan period. Including depletions due to past dewatering activities, the total lagged depletion to the river system in this plan period is 82.82 acre -feet, as shown on Table 7. Replacements The sources of replacement water are 0.5 Rural Ditch Company ( "RDC ") shares owned by the Applicant, and fully consumable water leased from the City of Aurora. The North Farm Property (area to be mined) was historically irrigated with 1.3 RDC shares. Bestway's ownership consists of all 1.3 of these shares, of which 0.5 shares are to be used for this plan. A historical consumptive use analysis on the Shores gravel mine property (Booth Farm) was performed by Civil Resources for Central Colorado Water Conservancy District in water court case 01CW255. The diversions and potential consumptive use information from that change case was utilized for these North Farm shares. RDC consist of 50 total shares. As shown in Table 1, the average farm head gate delivery (for the period of 1967 through 1996) is 5,679 acre -feet per year. This equates to a pro -rata average diversion of 147.7 acre -feet per year for Bestway's 1.3 shares. Using a ditch loss of 15 %, the total farm head gate delivery represented by Bestway's 1.3 shares is approximately 125.5 acre -feet per year. On average, the 1.3 shares were historically used to irrigate 11.4 acres of corn, 2.1 acres of sugar beets, and 23.6 acres of pasture grass, all of which have been taken out of production due to the gravel mining operation. A consumptive use analysis using the modified Blaney - Criddle method within the IDSCU model estimates a historic consumptive use of 57.5 acre -feet per year for the 37 acres of the North Farm Property. Actual crop consumption was limited to the lesser of the potential consumptive use and the product of the farm head gate delivery times the assumed irrigation efficiency of 55 %. The actual consumptive use of the RDC shares averaged 47.8 acre -feet per year for the 37 acres of the North Farm Property. Return flows were estimated to be 40% surface runoff and 60% deep percolation. The return flows from deep percolation were lagged to Saint Vrain Creek using a Glover analysis. The following parameters were used in the model to lag the deep percolation return flows: transmissivity (T) = 72,300 gallons per day per foot, specific yield (SY) = 0.2, the distance to the creek (X) = 2,520 feet, and a now flow boundary (W) = 10,000 feet. The attached Table 2 provides a monthly schedule of total lagged deep percolation return flows to the river system, shown to be 46.62 acre -feet for this plan period. Bestway has contracted with Central Colorado Water Conservancy District ( "Central" or "CCWCD ") to use Central's Rural Ditch augmentation station. Bestway must provide accounting from Central that clearly show's Bestway's 0.5 shares were returned to the river to claim credit for these shares. Bestway has a long term lease from the City of Aurora ( "Aurora ") for 49 acre -feet of fully consumable water to be released from the Metropolitan Waste Water Treatment Plant (WDID 0200700) located in the SW ' of the SW ' of Section 1, Township 3 South, range 68W, on the South Platte River approximately 44 miles upstream from the Saint Vrain Creek confluence. The longterm lease is currently used for Bestway Concrete Well No. 1 (aka the Litvak Well, WDID 0210164) in accordance with the Bestway Concrete Augmentation plan (water court case no. 04CW224) and Bestway's Brighton Combined SWSP (WDID 0202587). Bestway has added to this lease 49.37 acre -feet of water for the months of November 2012 through February 2013 to be released for this Shores SWSP. Aurora effluent could be made available for replacement of depletions from the Shores Pit by exchanging up the Saint Vrain Creek to the location of depletions on Boulder Creek so long as exchange potential exists. The pit is located adjacent to the Saint Vrain Creek downstream of the Last Chance Ditch and it is expected that there will be an exchange potential between the pit and the South Platte River. The Applicant