2011-08-30_HYDROLOGY - M2009018 - Laserfiche WebLink

Home Browse Search

Cheryl Signs, P.E. Page 3 Heintzelman Pit August 26, 2011 Replacements The operator proposes to provide replacement for this pit using water rights owned in the Last Chance Ditch, Rural Ditch, Hayseed Ditch, lined gravel pits (112 Reservoir, Dakolios Reservoirs and Von Ohlen Reservoir), and /or junior water rights decreed in case no. 2001 CW274. The Last Chance Ditch's historical use was previously analyzed in the original SWSP for the Kurtz Pit (M99 -006). This SWSP request revises the analysis period and the ditch loss used in the Kurtz SWSP and the crop mix identified in the 2006 SWSP request for the Heitzelman Pit. A total of four shares of the Last Chance Ditch will be used in this SWSP. The Applicant owns one share of the outstanding 20 shares of the Last Chance Ditch. The one share of the Last Chance Ditch was historically used for irrigation on a portion of the Heintzelman mining site (108.7 acres). The crops irrigated were taken from the mix analyzed for the Kurtz site. The historical use of the irrigation supply was quantified using the average monthly diversion from 1949 through 1974. The average consumptive use from the dry years of 1954 and 1963 was more than the average period; therefore the average results were used. The ditch Toss used in the consumptive use analysis was 10 percent based on the ditch location, its length, and previous experience. Water in excess of the irrigation requirement was added to the soil moisture bank, which was assumed to be three feet deep with a water holding capacity of 0.2 inches of water per inch of soil. The consumptive use analysis for the one share averaged 188.78 acre -feet per year with a non - irrigation season return flow obligation of 6.34 acre -feet (Table 4). The Applicant also owns 3 shares of the outstanding 20 shares of the Last Chance Ditch. The 3 shares of the Last Chance Ditch were historically used for irrigation on the Kurtz Pit mining site (264.7 acres). The historical use of the irrigation supply was quantified using the average monthly diversion from 1949 through 1974. The ditch Toss used the consumptive use analysis was 10 percent based on the ditch location, its length and previous experience. Water in excess of the irrigation requirement was added to the soil moisture bank, which was assumed to be three feet deep with a water holding capacity of 0.2 inches of water per inch of soil. The consumptive use analysis for the three shares averaged 478.85 acre - feet per year with a non - irrigation season return flow obligation of 31.07 acre -feet (Table 5). The subsurface return flow was lagged to the stream using the IDS AWAS stream depletion model to the Saint Vrain Creek. The aquifer characteristics used in the model are: transmissivity (T) = 100,000 gallons per day per foot and specific yield (SY) = 0.28 (based on the USGS Water Supply Paper 1662D). As mentioned in the depletion section, the nearest stream is a natural seepage ditch that originates uphill from the site and flows continuously through the west side of the property to Saint Vrain Creek. The distance from the centroid of the irrigated land to the seepage ditch = 450 feet, and the location of the parallel impermeable boundary was estimated to be 1,100 feet from the stream. Rural Ditch water was previously analyzed in the original SWSP for the Durham Pit (M78 -056). VCI owns four shares in the Rural Ditch that were historically used to irrigate 158.9 acres on the 112 - Reservoir parcel site. Consumptive use credits from the 4 shares of the Rural Ditch that are not used to replace depletions during the irrigation season will be stored in the 112 Reservoir, Dakolios Reservoirs and Von Ohlen Reservoir and subsequently released to replace non - irrigation season depletions. An application for a change of water right (to allow the applicant's Rural Ditch shares to be used in addition to irrigation for augmentation, replacement, exchange, commercial, industrial, recreational, piscatorial, wildlife propagation and storage) and approval of a plan for augmentation was filed with the Water