C150138 feas study

• Contract/PO #: C150138
• Contractor Name: Supply Irrigating Ditch Company
• Contract Type: Loan
• Water District: 0
• County: Boulder
• Loan Projects - Doc Type: Feasibility Study

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PROJECT SERVICE AREA
The service area of for the SIDC includes approximately 8,500 acres of irrigated farm land in
Boulder County, Colorado. The approximate service area boundaries are shown on the map in
Figure 1. Knoth Reservoir is located in Boulder County in Section 7, Township 3 North, Range
69 West.
Crops grown in the service area include corn, beets, grain including wheat and barley, alfalfa hay,
and pasture grass. An approximate division of crops and planted acreage is as follows.
Crop Type No. of Acres
Alfalfa Hay 4000
Corn 2500
Grain 1350
Beets 400
Pasture Grass 250
8500 acres
Average crop yields per acre in this area are: 4 tons of alfalfa hay; 18 tons of beets; 150 bushels
' of corn, 65 bushels of winter wheat, 50 bushels of spring wheat, 18 tons of silage, 1600 pounds
of dry beans, and 78 bushels of barley.
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Since the Supply Ditch is approximately 18 miles in length there are many soils and soil types
found along the system. The ditch will be divided into two major divisions with the first reach
being from its point of diversion in Section 20 T3N, R70W to approximately the Highland
Reservoir located in Sections 5 and 6, T3N, R69W. The soils in the first reach consist of
predominantly Renhoill silty clay, Samsill clay, Kutch clay loam, and Nunn clay loam. The
predominant soil associations are the Samsill-Shingle association and the Weld-Colby association
as shown on the Generalized Soil Map, Boulder County Area, Colorado from the Soil Survey of
Boulder County Area, Colorado, United States Department of Agriculture, January 1975. These
soils are nearly level to moderately steep, well drained with clay or clay loam surface soils
underlain by shale or sandstone at 20 inches to 4 feet. The water intake rate is slow and the water
holding capacity is low to medium. There is generally no water table in this area unless perched
on the shale.
The second reach of the supply ditch from the Highland No. 2 Reservoir to Mead consists of soils
' from the Weld-Colby association and the Nunn-Heldt association. The predominant soils in the
Weld-Colby association are moderately level, deep, well drained soils formed on upland slopes.
These soils have slow permeability, available water capacity is high, and roots can penetrate to
' a depth of 60 inches or more. Soil reaction is moderately alkaline and is strongly calcareous
throughout the profile. The predominant soils in the Nunn-Heldt association are level to
moderately level, deep soils on terraces and uplands. These soils are well drained, have slow
' permeability, available water capacity is high, and roots can penetrate to a depth of 60 inches or
I' Knoth Reservoir-Feasibility Study Page 2
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