Laserfiche WebLink
Capacity: The capacity of the inlet canal is 600 cfs, and has not changed over time. At times the <br />capacity has historically been a constraint on the amount of water that can be diverted at <br />the headgate. <br />Measurement Device: Diversion measurements on the inlet canal are made using a stilling well <br />and continuous recording clock located approximately 1 mile below the South Platte <br />River headgate. Water may be returned to the South Platte River via a wasteway located <br />between the headgate and the measurement point. <br />The District installed a second measuring device on the inlet canal in 1996. This device <br />is located at a point just above the reservoir and is periodically used, along with the upper <br />measurement point, to quantify seepage losses. This measurement point may be used in <br />future operations of the District's plan for augmentation to help quantify recharge credits <br />from inlet canal seepage. <br />Conveyance Efficiency: Seepage studies performed on the inlet canal indicate that losses <br />generally range from 30% to 50% depending on diversion rate. A minimum diversion <br />rate of 100 cfs is required to convey water to North Sterling Reservoir, i.e. there is a 100 <br />percent loss below diversion rates of 100 cfs. <br />Return Flow Locations: Seepage losses from the North Sterling Inlet Canal drain to areas <br />below the canal and above the South Platte River upstream of the confluence of Cedar <br />Creek and the South Platte River, which includes the Logan Irrigation District. <br />Approximately 90% of the seepage from the inlet canal occurs upstream of the Sterling <br />No. 1 Ditch headgate. Lands in these areas rely solely on shallow groundwater for <br />irrigation supply, and the seepage losses from the inlet canal serve to replenish the <br />alluvial aquifer. Returns flows from operation of the inlet canal occur at a fairly uniform <br />rate because of direct flow diversions during the irrigation season and storage diversions <br />during the non-irrigation season. <br />HydroBase Data: Diversion records are generally available in Hydrobase from 1969 through <br />2002. North Sterling Irrigation District is responsible for collecting diversion records at <br />the measuring device located on the inlet canal. Records are then reported to the Water <br />Commissioner in Water District 1. Paper records were provided by the District and <br />extend back to 1926. According to the District records, the total historical diversions <br />through the inlet canal over the 1929 to 2002 time period average approximately 98,000 <br />acre-feet per year including diversions for storage and direct irrigation use. HydroBase <br />indicates separately the amount of water that is diverted to storage and the amount that is <br />directly used for irrigation. The District also separately accounts for water diverted under <br />the direct flow and storage rights. <br />2) North Sterling Reservoir (Structure ID 0103551) <br />North Sterling Reservoir is an off-channel storage facility located approximately 63 miles <br />upstream from the Colorado-Nebraska state line and approximately 12 miles north-northwest of <br />the Town of Sterling. The reservoir was completed in 1912 and is used for irrigation and <br />recreational purposes. <br />North Sterling Irrigation District.doc Page 5 of 11 <br />