WSP12980

• File Number: 8210.140.20.C
• Description: Imperial Irrigation District ‎(IID)‎
• State: CA
• Basin: Colorado Mainstem
• Date: 1/9/1996
• Author: Imperial Irrigation District
• Title: Water Requirements and Availability Sutdy ‎(draft)‎
• Water Supply Pro - Doc Type: Publication

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

of the current practice minus the one percent tailwater resulting from the linear tracking sprinkler
system.

By determining the water conservation savings due to reduced tail water for each of the major
field crops, an estimated water conservation potential can be determined. For example, if all
major field crops were converted to linear tracking, about 200,000 acre-feet (0.51 AF/AC) are
estimated to be saved. On the other hand, if selected vegetable crops (artichokes, asparagus, and
sweet corn) were to be irrigated by linear tracking, an additional 10,000 acres might be converted
to linear tracking. The estimated savings would be about 13,500 acre-feet (1.30 AF/AC).

Table IJ-':B. 7-1 A verage Linear Tracking Irrigation Conservation Potential

Crop IID Area Estimated Potential Saved Water
Selected Vegetables 10,465 AC 1.30 AF/AC
Field Crops 399,167 AC 0.51 AF/AC

Two considerations exist regarding the assumption that this project conserves 99 percent of the
pre-project tailwater. First, actual water conservation amounts may lower depending on soil
type, cropping pattern, and the previous irrigation practice. As the system is tried in various
locations on different soil types and cropping patterns, this information will become available.
Secondly, one of the expected advantages of this system is increased yield. Thus, while
irrigation efficiency may increase, actual water conservation may be less than the available
tailwater volume due to increased crop water use.

IV.B.B Irrigation Water Management
As stated previously, the impact of irrigation water management on the amount of conserved
water obtained from each of the proposed on-farm projects cannot be over emphasized.
Irrigation water management includes irrigation scheduling to determine how much water to
apply and when, irrigation event evaluations, and increased management effort to use water more
efficiently. Irrigation scheduling methods include soil-water balance models, infrared
thermometers, experience and combinations of these methods. Every grower's irrigation water

Draft: Subject To Revision 1/2/96

49