habitat, streambank protection, and water quality 

 improvement. 



G) To apply soil and water conservation to 

 the land. The CDD will encourage CDs to annually 

 review their conservation plans with their 



cooperators. See Part B. Objective 24 of the Work 

 Plan. 



Rationale: Conservation plans, when proper- 

 ly followed up, can give conscientious attention to 

 soil and water conservation. 



IRRIGATION WATER MANAGEMENT 



Situation 



Irrigation water is vital to Montana. Over 95 percent 

 ot the water withdrawn from Montana drainages is used 

 for irrigation. More than 2.5 million acres in the state are 

 fully or partially irrigated. Total water use for irrigation 

 amounts to 12.4 million acre-feet of water over a six- 

 month irrigation season each year. Surface water provides 

 99 percent of the irrigation water; 1 percent comes from 

 ground water (DNRC 1975). Nearly 80 percent of Mon- 

 tana's irrigated land is in hay or pasture. Other major ir- 

 rigated crops include small grains, corn siilage, sugar 

 beets, beans, and potatoes (SCS 1980). 



Although gravity ditch and lateral systems have been 

 by far the most extensively used, sprinkler systems are 

 becoming more and more popular, using easily portable 

 aluminum pipe with pumps or gravity feed drawing from 

 streams, ponds, or wells (DNRC 1975). Where gravity flow 

 sprinkler systems can be used they save substantial 

 amounts of electrical power. In many places in Montana 

 there is sufficient fall to generate the pressure needed. In 

 Ravalli County five such projects have repaid their cost by 

 irrigating several thousand acres efficiently with almost no 

 power input. Drip systems are available that do not re- 

 quire high-pressure application of water. Because water is 

 delivered slowly, less water is lost by evaporation or 

 runoff. Both the water and energy used by a drip system is 

 about 50 percent of conventional systems (MHD 1977). 



Inefficient irrigation water delivery and application is 

 often a problem. It is estimated for Montana that only 47 

 percent of the water diverted actually reaches the farm. 

 Of this 47 percent, 52 percent is consumed by the crop; 

 the other 48 percent is lost because of delivery and on- 

 farm inefficiencies (DNRC 1975). However, this situation 

 can be improved. For example, in the Montana portion of 

 the Missouri River Basin, overall irrigation efficiency is a 

 poor 20 percent. If an additional 600,000 acre-feet of ir- 

 rigation water were provided by implementing structural 

 and management improvements, reservoir storage for late 

 season irrigation would result and overall efficiency could 

 be increased by 35 percent for a total efficiency of 55 per- 

 cent (Missouri River Basin Commission 1980). A further 



look at irrigation water management shows that one- 

 fourth of the irrigated lands in Montana do have adequate 

 on-farm irrigation systems but only half of these lands 

 receive good irrigation water management (SCS 1978). 



The water saved by good irrigation water manage- 

 ment can be put to several beneficial uses depending on 

 the area's needs and the water rights in the area where the 

 water savings are made. 



Concerns 



Irrigation efficiency in Montana needs to be 

 upgraded. Even though water supply may be ade- 

 quate, if irrigation methods are ineffective, water 

 will be wasted. Managerial as well as structural im- 

 provement is recommended by the CDs. Increas- 

 ed use of gravity flow sprinkler systems and drip ir- 

 rigation is needed to conserve water and energy. 



Objectives 



A) To provide increased assistance to irriga- 

 tion operators for irrigation water management 

 training and irrigation systems improvement. The 

 CDD will support efforts of the Montana 

 Cooperative Extension Service and SCS to provide 

 increased irrigation assistance; the CDD will also 

 assist the Cooperative Extension service to 

 publicize its irrigation scheduling models. See Part 

 B, Objective 25 of the Work Plan. 



Rationale: Irrigators need assistance with ap- 

 plying current irrigation technologies in order to 

 improve their efficiencies. 



B) To improve irrigation efficiency informa- 

 tion systems the CDD will encourage interested 

 CDs to develop their ability to test and monitor ir- 

 rigation efficiency, including delivery and applica- 



