2011-03-21_HYDROLOGY - M1999098 - Laserfiche WebLink

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Jared Dains South Platte Combined Replacement Plan March 21, 2011 Page 9 previous estimated of the net yield due to the computed return flow obligations based on the previous year's actual water deliveries. **11.5% of the Coffin & Davis Ditch was set aside for irrigation of 36 acres Coffin & Davis Ditch The Coffin & Davis Ditch is currently owned by the City of Longmont ("Longmont") (71.47%) and Don Sherwood (28.53%). Pursuant to a mining lease agreement with the City of Longmont, which was amended in December 2009, Aggregate has the right to use Longmont's ownership of the Coffin & Davis Ditch. Additionally, pursuant to the December 2009 agreement Longmont is responsible for the augmentation of the Distel Pit site after October 31, 2011. Pursuant to a 1993 mining lease with Don Sherwood, Aggregate has the right to use 28.53 percent of the Coffin & Davis Ditch. Mining has permanently removed the historically irrigated area from irrigation. Since the last plan Longmont completed an evaluation of the Coffin& Davis Ditch in case no. 2009CW271. From this analysis, Longmont determined a net stream depletion of 534.80 acre-feet. Of this amount 88.5% or 473.30 acre-feet is available for this SWSP. The remaining 11.5% of the Coffin & Davis Ditch water rights will continue to be used for irrigation of 36 acres. Smith & Emmons Ditch Aggregate owns 1.5 of 8 total outstanding shares in the Smith & Emmons Ditch Company. The 1.5 Smith & Emmons Ditch shares were historically used to irrigate 68 acres of pasture grass. Using a Blaney-Criddle analysis the potential crop consumptive use for the 68 acres was determined to be 108.7 acre-feet. Assuming a 10% ditch loss and 55% farm efficiency the dry year consumptive use was determined to be 91.65 acre-feet. The applicant may only utilize the 1.5 shares of Smith & Emmons Ditch at such time as all required measurement and bypass structures have been installed and approved by the water commissioner. Leggett-Owens Reservoir Donald J. Sherwood owns 19.6 shares of the Leggett-Owens Ditch and Reservoir Company, which Aggregate may use for augmentation pursuant to the mining lease agreement. During an average year the 19.6 shares represents 60 acre-feet of water and can be released when needed. The consumptive use credit available from the 19.6 shares is estimated at 33 acre-feet, based on a 55% efficiency. The applicant may only utilize the 19.6 shares at such time as all required measurement and bypass structures have been installed and approved by the water commissioner. Godding, Dailey & Plumb Ditch Aggregate owns three total shares in the Godding, Dailey & Plumb Ditch. The consumptive use for this water right was quantified in the SWSP approved on May 1, 2001 for the Distel Pit. That analysis found that the net annual consumptive use from two Godding, Dailey & Plumb Ditch averaged 56.20 acre-feet, assuming a 10% ditch loss and 55% farm irrigation efficiency. Therefore, the dry year consumptive use for the three shares was determined to be 84.30 acre- feet. The applicant may only utilize the 3 shares of Godding, Dailey & Plumb Ditch at such time as all required measurement and bypass structures have been installed and approved by the water commissioner. City of Longmont Lease Aggregate is not proposing to use fully consumable water leased from the City of Longmont in this