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Show PART VI ADDITIONAL STUDIES REQUIRED The findings of this report, especially the appraisal on water and related land resource problems, show the need for more detailed inves- tigations. Solving these problems will require coordinated planning efforts of all concerned federal and state agencies, and local groups. Intensive studies, such as the Type II and Type IV River Basin studies, are needed to provide guidelines for coordinated planning. These studies will also provide detailed information on specific problems, project development, and related programs. Type IV River Basin studies have been completed or initiated in all of Colorado that is within the region. The San Juan River Basin in Colorado, Arizona, New Mexico, and Utah has the highest priority for completion. In Utah and Wyoming the Green River Basin ranks next in order of priority. Lowest priority for Type IV studies is assigned to the remainder of eastern Utah not included within initiated studies. The role of watershed management to maintain environmental balance under intensified land and water use cannot be fulfilled without more information relating to the ecology and other aspects of the regional environment. Additional surveys are needed on current watershed con- ditions, plant cover, soils, erosion susceptibility, sediment yield rates, and the source of salts in the streams. The impact of water modification on the environment should carefully be studied to deter- mine the effect of increased flows on stream regime, fisheries resources, and flood plain ecology. Research studies are needed. Sources of sediment and dissolved solids which enter the stream system due to mans1 activities are not fully documented. In many instances, it is difficult to differentiate between man-related, and geologic or natural problems. Source areas should be located and identified as to the cause and effects of pro- blems such as: improper land use, inadequate treatment measures, and poor management. More definitive information is needed on the dissolved solid pollution factor. The present practice of tabulating information from measured sources and assessing the remaining, unaccounted for, portion of the load to irrigated lands is too general, and may be inaccu- rate. Movement of sediment out of the region has been curtailed by reservoirs; however, the in-basin movement of sediment needs to be controlled. Improved vegetal cover conditions and land use and manage- ment reduce sediment, but detailed information as to the effects of measures and practices is needed for effective planning. Qk |