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Show Unscreened pumping plants and canals along the Sacramento River divert small salmon in num- bers during downstream migration from the river to irrigated land. State laws designed to prevent this appear to be ineffective. Wildfowl habitats in the Sacramento and San Joaquin Valleys have been lost as agriculture has taken over large areas of former feeding and resting areas. If the species formerly using these areas are to be maintained in quantity, wildfowl refuges and shooting areas are needed. To satisfy this need, over 1,000 second-feet of water will be required for the purpose. Plans for water use should therefore take into account these requirements. Provision of waterfowl refuges and shooting areas on the Pacific flyway can help to alleviate crop depreda- tions that result from restricted and inadequate habitat. These depredations are estimated to have reached a peak of a million dollars in 1943. Feed- ing areas, provided later, have reduced this damage. The State is prepared to establish additional waterfowl management areas but because of objec- tions in some farming areas it appears to be difficult to agree upon sites. Conclusions The adverse effects of water projects on fish and wildlife aresources in the Central Valley heretofore have been considered generally on a project-by- project b»asis as individual problems have arisen. A more logical procedure would be the development of a comprehensive plan for the preservation and enhancement of fish and wildlife values which would be developed as part of a comprehensive multiple- purpose water resources program for the basin. 9. Measures for Mosquito Control The Problem The efifect of proposed water regulation and use programs on the mosquito problem. The Situation The development of water control and use pro- grams in the Central Valley Basin has been exten- sive during the past half century. Current develop- ment and planning are for an increased rate in this development. Important as is the elimination or control of mosquitoes in connection with water projects, meas- ures to accomplish this frequently have been under- taken only after completion of the projects. By that time, mosquitoes may have become a nuisance and a danger. Measures to destroy mosquitoes and their breed- ing places are available. If this knowledge is ap- plied and adequate controls incorporated in the original plans for the project, many of the problems that now arise after the project is built will be less serious or will not occur at all. Water surfaces which may create mosquito habi- tat in the valley have increased continuously dur- ing the last two decades. During the critical water years 1927-34 an average of a little less than 3 million acres were irrigated annually in the Central Valley. This is only 45 percent of the total irri- gable area of the basin. The average annual in- crease during the next decade amounted to about 67,000 acres per year. The presently authorized Federal Central Valley Project, excepting the American River service area, includes water sup- plies sufficient for about 550,000 acres of new land and 500,000 acres in need of supplemental supply. This development is expected to be nearly com- plete by June 30, 1956, and is scheduled for com- pletion at the rate of about 80,000 acres (maximum) a year. Mosquito control measures are not keeping pace with water control and use programs. The 32 organized mosquito abatement agencies within the basin derive their income from taxes, but they are not prepared financially to cope with an ever-growing increase in mosquito control re- quirements. They now serve a little more than 10 million acres or about 27 percent of the area con- tained within the drainage basin. Conclusion The need for mosquito control should receive early recognition in Central Valley water planning. Adequate participation by specialists in this field in the planning, design, construction, and opera- tion of water control projects of any size should be provided. It is essential first to know precisely what should be done to protect public health in the area, and then to take necessary preventive measures. 138 |