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Learn-Assess State and local governments play two major roles in funding water resources development: constructing and operating their own projects, and financing their share of and maintaining the projects built for them by the federal government. Tremendous variations exist in the extent of state and local involvement in each role. As of 1988, 23 states provided technical assistance to communities for flood control; many more states are directly involved in local structural flood projects in other ways. Home Leaminl!: Center Back Dams and Reservoirs Storing flood water in reservoirs can modify floods by reducing the speed at which the water flows, limiting the area flooded, and reducing and altering the timing of peak flows. However, misconceptions about or lack of understandi rg <f darns can create an exaggerated sense of security. Reservoir sedimentation can significantly reduce flood control capacity. Competing uses of the reservoir can impair flood control because those relying on the darn for recreation and water supply (irrigators, manufacturers and residential users) often press for continued high pool levels, resulting in less storage space in the reservoir for flood waters. In addition, most dams are designed for purposes other than flood control, although they do have the temporary effect of flood reduction through storage. The availability of water, power, or recreational opportunities associated with darns therefore often attracts new development regardless of the flood risk or the ability of the darn to provide flood protection. Over time, without adequate land use regulations, encroachment onto the floodplain downstream of dams can prevent proper operation of the structure and increase exposure to flooding. Once signs of darn failure become visible, breaching often occurs within Page 12 of36