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S-7 I~. .. _ .l~i- 'i\l\' "':(1: -:-\:' N A c;.;l .... Drains and Washes SUMMARY (Continued) Under the no-aqtion alternative, the aquatic reaources of the drains and washes would r~main in their present poor quality condition, with little or no recrea~ional use. The discharge !and water quality in the drains and washes of the Grand Valley would be altered by developing either alternative A .or B. In general, major dtains and washes with year-round flow would have in- creased flow and .d~creased salinity during the irrigation season and decreased flows during the nonirrigation season. Some of the smaller intermittent drains,! dependent entirely on seepage, would be dried up. Vegetation Under the no-a4tion alternatiye, a. gradual but continuous loss of native vegetation in! the valley WOdldlikely occur as a result of urban expansion, farm impr9vements, sand and gravel production, and other fac~ tors. Marsh and c04tonwood vegetation. types would be particularly af- fected because of th~ir scarcity. Stage One wildlife measures would be implemented to offset wildlife losses associated with Stage One improve- ments. Alternatives A.jlnd B would have similar impacts on the vegetation of the valley. Short!-term effects for both alternatives include clearing vegetation (about 3 .~OO acres or an average' of 165 acres each construc- tion year) within c?nstruction rights-of-way, while long-term effects would be related to teduced groundwater which supports wetland vegeta~ tion. A net acreag~ loss of 200 to 300 acres of wetland vegetation types would occur wi~b either alternative. Wildlife The Fish and Wi!ldlife Service prepared a Coordination Act Report (1984) assessing unit;impacts and recommending measures to offset losses. Under the no-action a~ternative, the.'wildlife in the valley would gradu- ally be reducedwithi conversion of habitat to urban, industrial, and agricultural uses. !Riparian habitat .'losses along the Colorado River would be especially s!Lgnificant beciuiseof the present scarcity of this type of habitat and !because of its importance to wildlife. Wildlife measures for Stage One would be implemented to offset habitat losses now occurring due to Stag, One construction. Under alternativ.s A and B, additional wildlife losses would occur primarily as a resultiof clearing habitat during construction and long- term losses of habitat caused by seepage reduction from canals and lat- erals. The detentioh dike and ditch system would increase moisture available for plant g~owth north of the Government Highline Canal which, in turn, would benefllt local wildlife populations. Observations in Stage One have indicatbd that habitat losses have occurred in zones along canals and laterals, thile changes are not readily apparent outside of