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C',"! L') ,::.; .....c 9 '- Diffused Areas (upland areas) Management Improvement Needs - The contri- bution of salt to the Colorado ];liver from the area outside the ilTigated lands is controversial and not well studied. It is known that the salt loading potential is high with highly saline soils and salt layers in the profile. Studies made by the USGS and BLM in the Badger Wash a:~ea and by SCS in the Indian Wash area indicate that the average sediment yield may be OLe acre-foot per square mile per year. Some samples of nediment have ShOw'll a 5 percent by weight of soluble salt content. Using this limited data, the watershed contributes an estimated 90,000 tons of salt to the Colorado River annually. An additional estimated 50,000 tons i,s contributed to the river by subsurface flows. There are approximately 175,000 acres of non-federal rangelands wi tlilE the study area with nearly all of the area rated in fair to poul' conch- tion. Rangelands in poor condition in zones recelvlng 12 inches or DJore of annual precipitation could be reseeded. An estimated 17,000 acres al'e in this classification. An estimated 15,000 acres can be tl'eated wIth erosion control dams, range pitting, or contour furrows. The above are treatment measures that can be considered to reduce seal- ment yield3. Such treatment has shown up to a 50 percent. sedilnent. yield reduction in other studies on salt desert range. Objectives, Scope and Expected Results The overall objective of the U. S. Department of Agr,icul ture p3.1't ;"'[13'- tion in salinity control studies in the Grand Valley a:cea i~s tr.J ,jpter-, mine the contribution of salt loading from the irrigated and NtLed upland areas and to determine the opportunity for reducing Sh, loading through improvements on irrigated farms and reduction of eronlun and sediment delivery from the upland areas. 'The present em-farm systems and water management practices will be inventoried as a basis for det.er- mining improvements which might be made. It is expected that a program will be developed setting forth water requirements, irrigation system changes, drainage requirements, and related soil and crop management requirements best suited to accomplishing the above ob,jective a.nd main- taining a strong and viable agriculture in the Grand Valley. The study will utilize completed and on-going research and demonstration work in the area and the investigational studies by the Bureau of HecJa- mation of the canals and laterals. Full use will be made of available water use data from the irrigation companies and as analyzed by the Colorado Water Conservation Board,