2019-01-30_HYDROLOGY - M1992069 - Laserfiche WebLink

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Aggregate Industries South Platte Combined SWSP January 30, 2019 Plan IDs 3614, 4773, 3624, 4772, 4616, 3437, 3376, 3650, 3668, and 5475 Page 10 of 21 acre-feet annually, of which 265.24 acre-feet are anticipated to be utilized in this SWSP. (The remaining 29.55 acre-feet are reserved for use in case no. 2007CW198.) Westminster Annual Lease Pursuant to a March 4, 2009 Consumable Water Lease Agreement with the City of Westminster, Aggregate may lease up to 519 acre-feet of consumable water annually, with a minimum lease of 150 acre-feet per year unless changed by mutual agreement between the parties. The agreement is valid through December 31, 2019. Deliveries under this lease are available from November 10th through March 20th from either the Metro Wastewater Treatment Plant or the Big Dry Creek Wastewater Treatment Plant. For 2019, Aggregate and Westminster have agreed to a total annual delivery amount of 146 acre-feet. A copy of the proposed 2019 delivery schedule, dated November 8, 2018, is attached. For this SWSP, transit losses were assessed assuming deliveries will be from the Big Dry Creek Wastewater Treatment Plant. Notice must be provided and approval made by the water commissioner at least 48 hours prior to the release of replacement water, or as required by the water commissioner, and must identify which source the replacement water will originate from (the Metro Wastewater Treatment Plant or the Big Dry Creek Wastewater Treatment Plant) to allow confirmation of release and that water was delivered. Thornton Lease Aggregate has a perpetual lease of 10.53 acre-feet of fully consumable effluent from the City of Thornton, which will be released from the Metro Wastewater Treatment Plant at a rate of 0.035 cfs daily from November 1st through March 31st. Fulton Ditch Aggregate owns a total of 96 shares in the Fulton Ditch Company, consisting of 62 shares obtained from Cooley Gravel, 22 shares from CAMAS, 6 shares from C&M Aggregates, and 6 shares from Hill & Peterson. For 2019, Aggregate intends to utilize their 62 Cooley Gravel shares for replacement under this SWSP. (The 22 CAMAS shares, 6 C&M Aggregates shares, and 6 Hill & Peterson shares will be leased to others for irrigation purposes). Prior to 1977, the 62 Cooley Gravel shares were used in two blocks: 30 of the shares were owned by the Montandon Trust and used for the irrigation of 48.7 acres, and 32 shares were owned by the Palombos and used for the irrigation of 31.1 acres. The shares were purchased by Walt Flanagan & Company in 1977 and little is known about the use of the shares after that time. The historic consumptive use analysis utilized a parcel-specific analysis for the period of 1919 to 1977. A total of 40 shares were used on the Montandon parcel prior to 1964, with 10 shares being sold off in 1964. The historic consumptive use analysis assumed that the subject 30 shares irrigated 75% of the Montandon parcel (36.5 acres) prior to 1964 and 100% of the parcel (48.7 acres) from 1964 to 1977. The crop mix for the Montandon and Palombo parcels was assumed to reflect the mix of crops for the Fulton Ditch as a whole as identified in the 1956 CDSS irrigated lands GIS layer, consisting of 44% alfalfa, 26% corn, 15% dry beans, 13% pasture grass, 1% small grains, and 1% sugar beets. A ditch loss of 20% and irrigation efficiency of 65% were utilized for the analysis, which appear reasonable based on review of aerial photos and topography. Based on the above, the historic consumptive use of the 62 Cooley Gravel shares is estimated as 1.87 acre-feet per share. Return flow obligations were allocated as 50% surface return flows and 50% subsurface return flows. The 62 shares to be used for replacement purposes under this SWSP will be delivered through the augmentation station owned by the South Adams County Water & Sanitation District located just downstream of the ditch headgate. The expected consumptive use credit for the 62 Fulton Ditch