OCR Text |
Show ( b) Methods of determining exact essential minimum flows for fish have not yet been developed; ° however, there are methods available which are reliable enough to estimate the flows necessary to preserve existing habitat; 109 ( c) Habitat studies have also indicated that reducing peak natural flows might not be harmful and would possibly improve a fishery; 107 ancj ( d) A distinction must be made between the capacity of a stream to produce fish and its capacity to provide fishing. Partial diversion of those flows in excess of natural minimums could substantially curtail the amount of angling utilization of a stream by causing a reduction in water area. At the same time fish production could remain unaffected. The estimates of fishing losses and gains determined by the Bureau of Sport Fisheries and Wildlife should not be interpreted as representing an assessment of environmental impact since the unit of evaluation used consisted of " man- days of fishing" which was not derived from an analysis of fish production and habitat. Many nonenvionmental factors can significantly affect the number of man- days of fishing a stream can support. Among these factors are angling regulations, ownership of streamside land, accessibility, weather, and social attitudes and conditions " Man- days" of fishing can be used to reflect changes in recreation associated with the Bonneville Unit. Table C- 19 presents a summary of the stream fish habitat affected by construction and operation of the Bonneville Unit. The effects construed as bein adverse ( inundation, reduced flows and excessive flows) are related to the fishery quality of the streams as designated by the Utah State Division of Wildlife Resources,,'- 5 Also noted are those sections of stream where flows for fishery purposes would be improved. Those sections of stream rated as Class I, II, and III are considered as being of significant importance to the State fishery resource. |