WSP03538

• File Number: 8407
• Description: Platte River Basin - River Basin General Publications
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 1/1/1978
• Author: Colorado Water Resou
• Title: Impact of Irrigation Efficiency Changes on Water Availability in the South Platte River Basin - Preliminary Report
• Water Supply Pro - Doc Type: Report/Study

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ESTIMATED COSTS OF EFFICIENCY IMPROVEMENTS

Farm Irrigation Efficiency Improvement Costs

The United States Bureau of Reclamation (USDI, 1970) reported detailed

studies of field irrigation efficiencies of projects in the McCook, Nebraska,

and Torrington, Wyoming, areas. They began with existing efficiencies,

which they measured on 7 farms (31 fields) over a 5-year period. From

these data they concluded that there are three levels of attainable effi-

ciencies.

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(1) Existing system, improved management, no additional labor

On-farm irrigation efficiency can be increased by scheduling irrigations

according to monitored plant needs, rather than from a predetermined schedule

or advice from neighbors. Such scheduling can be carried out by the farmer

using resistance blocks and/or tensiometers, frequent sampling with an Oak-

field probe, or by keeping a detailed day-to-day moisture budget using

climatic data, The farmer would have to know the approximate water-holding

capacity of his soil and the approximate infiltration rates to carry out

this exercise,

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Although the cited reference claims that favorable results can be

obtained with a minimum effort on the part of the farmer, it is probable

that he will use management services to attain this level of control, if

such services are available. In eastern Colorado they are offered by at

least one company, at a rate of $4.50 to $5.50 per acre per year, depending

on farm size. This is a total management service and includes advice on

weed and pest control, planting dates, fertilization, etc, It is probable

that the irrigation scheduling cost is no more than half the quoted cost

for the entire package. Furthermore, farmers continue to use the service,

so it must pay for itself. That is, there must be an increase in return

or decrease in cost associated with the service, so it really costs nothing.

The level of improved on-farm irrigation efficiencies to be expected

were reported by the Bureau (USDI, 1970). They concluded that on-farm

efficiencies could be raised from a 44 percent average without improved

management to a 62 percent average with improved management, These values

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