SPDSS_Task5_KeyStructure_NewCacheLaPoudre

• Title: SPDSS Task 5 - Key Structure, New Cache la Poudre Irrigating Company and Cache la Poudre Reservoir Company
• Description: The New Cache la Poudre Irrigating Company and Cache la Poudre Reservoir Company has been identified as a key structure for the South Platte Decision Support System ‎(SPDSS)‎ consumptive use and surface water modeling efforts. The purpose of this Task 5 memorandum is to document physical, legal, and operational aspects of those key structures identified.
• Decision Support - Doc Type: Task Memorandum
• Date: 3/5/2005
• DSS Category: Surface Water
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153954
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: Leonard Rice Engineering

approximate dividing line for where return flows accrue. Seepage from the New Cache
System west of Sand Creek accrues to the Cache la Poudre River (approximately 60
percent). Drainages that carry return flow from the New Cache System to the Cache la
Poudre River include Law Drainage, Graham Seep, and Eaton Draw. Seepage from the
New Cache System east of Sand Creek accrues to the South Platte River (approximately
40 percent). Drainages that carry return flows from the New Cache System to the South
Platte River include Lone Tree Creek, Willow Creek (aka Galeton Draw) via Lone Tree
Creek, and Crow Creek.
Irrigated Crops: A 1987 study conducted by Colorado Water Resources and Power
Development Authority concluded that in 1970 total land irrigated by the Greeley No. 2
Ditch system was 42,500 acres. Of the total land irrigated, 14,900 acres (35 percent) was
estimated to be outside the Cache la Poudre Basin. It is not clear, from the information
provided in the referenced report, if the Greeley No. 2 System includes those lands under
the North Side Lateral or the North Side Extension.
Based on work conducted as part of this SPDSS project, approximately 85 percent of the
lands under the New Cache System are flood irrigated; the remaining 15 percent of lands
are sprinkler irrigated. While flood irrigation is currently the more common method of
irrigation, the use of sprinkler irrigation is growing. Sprinkler irrigation is more
prevalent at the east end of the system, particularly along the North Side Lateral and the
North Side Extension.
Crops grown under the New Cache System include the following: alfalfa, pasture grass,
corn, pinto beans, winter wheat, barley, carrots, onions, sugar beets, cabbage, and lettuce.
HydroBase Data: Historical diversions through Greeley No. 2 Ditch are recorded in HydroBase
under New Cache la Poudre Co D (WDID 0300929). Diversion records for Greeley No.
2 Ditch do not include water from Timnath Reservoir. The monthly data available in
HydroBase over the 1950-2002 period of record pertaining to the Greeley No. 2 Ditch
include the following:
Total River Diversions
• Complete record over 1950-2002 (see Figure 2)
• Historic diversion average of approximately 47,018 ac-ft/yr
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