30 percent. Also, neither agency had current information on range conditions, and only about half the grazing allotments had been evaluated in the last 10 years.

Increasing the fees on federal grazing land would remove the incentive for overgrazing that current low fees provide. Increased fees might help to improve the management and administration of the federal grazing system.

Drainage and Channelization

A U.S. Fish and Wildlife Service manual on stream channelization impacts (Simpson et al., 1982) estimated that as much as 70 percent of the overall riparian habitat associated with streams in the continental United States had been lost or altered and that much of this loss was associated with channelization activities. Unfortunately, there is no reference for the 70 percent figure nor any explanation of how it might have been derived, other than the following discussion, taken from the report. There is little information available on the extent of early (1800s) channelization activities of the U.S. Army Corps of Engineers (COE), but between 1940 and 1971, COE assisted in 889 stream projects totaling 11,077 miles of stream. The Soil Conservation Service (SCS) was involved in the channelization of 21,401 miles as of 1979. The U.S. Department of Agriculture estimated that 189,000 miles of open ditches had been constructed for drainage of agricultural lands by 1959. Bhutani et al. (1975) estimated that channelization and drainage for agriculture would average 6,600 miles per year through 1985. Arthur D. Little (1973) estimated that more than 200,000 miles of stream channel had been modified in the United States by 1972. If streams and rivers in the United States total approximately 3.2 million miles in length (Echeverria et al., 1989), 200,000 miles is approximately 6 percent of the total-quite different from 70 percent! A few states have assessed the extent of channelization. Lopinot (1972) reported that 26.8 percent, or 3,123 miles, of the interior streams in Illinois (excluding the Mississippi, Ohio, and Wabash rivers) had been channelized; this also is a much lower value than the 70 percent average estimated by Simpson et al. (1982), despite the fact that Illinois is a corn belt state where much of the original marshy prairie had to be tiled, ditched, and drained to make it suitable for agriculture. It is clear that an inventory of the nation's streams and rivers is needed, so that their condition can be assessed. This inventory should be updated periodically to track progress in protecting and restoring streams.

Impacts of channelization on habitat for fish and invertebrates include

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