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!.J.- m C nI11i1~'~-c-~;- c,,_ _'c --,- ~- .; ......-.+~~...~--_."..--.- ,~ "-1' - -~~~,.......,.,~_..-..~.. ..' -....~......,. ..-''''--''-'~-- " , ." .;, cc,.;, CC , ",c,c >'; , provided. Fisherman-use of the channel is expected to average 10,000 man-days annually and result in a net benefit of about $30,000. d. Rio Grande Project operation would increase the flows of the Rio Grande downstream from the mouth of the conveyance channel by about 100 second-feet. These flows would improve the quality of stream fishing in the 32 miles of the Rio Grande in Colorado and about 76 miles in New Mexico. Fishing use would increase by about 3,000 man-days in Colorado and about 10,000 man-days in New Mexico. Annual net benefits associated with the increased fishing use would amount to about $39,000. 2. Wildlife a. Big Game - Upland Game Effects of the project on big game, upland game and related hunting oppor- tunities, would be minor. b. Wetlands The project would have its greatest impact on wetlands and the various forms of wildlife dependent upon the wetlands and associated habitat for their sur- vival. For this reason, the discussion of the impacts of the project on wet- lands, vegetation and waterfowl production is in greater detail. (l) Definition - Wetlands - Wetlands are lands that are transitional between terrestrial and aquatic systems. The water table is usually at or near the surface, or the land is covered by shallow water. For the purposes of the Fish and Wildlife Service Wetland Classification System (Cowardin et. al. 1979), wetlands must have one or more of the following three attributes: (1) at least periodically, the land supports predominantly hydro- phytes; (2) the substrate is predominantly undrained hydric soil; and (3) the substrate is nonsoil and is saturated with water or covered by shallow water at some time during the growing season of each year. , (2) Im6acts - To help determine the impacts of the Closed Basin Division, San Luis alley Project on wetlands, the following information was revi ewed: (a) Wetland inventory maps; (b) 1978-1980 shallowest and deepest water table maps; (c) U. S. Geological Survey (USGS) predictive water table drawdown maps; (d) BR infiltration test data for 1979-80; and (e) Numerous letters of correspondence and data transmittal between BR and FWS. The project could have several impacts on wetlands, some of which are quantifi- able and others not. The more easily identified impacts are related to ' interruption of natural overland flow by the construction of the conveyance channel and direct effects of pumping. 14