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<br />000296 <br /> <br />Today, water orders by Boulder Canyon Project Contractors exceed available supplies <br />(7.5 maf in normal years) and Upper Basin depletions are about four million acre-feet per <br />year. Although the Colorado River mainstem reservoirs filled and flood control releases <br />were made in the 1980's and 1990's, increased uses and recent years of extreme drought are <br />causing reservoir storage to decline. <br /> <br />This condition of tightening water supplies and increased demands has raised important <br />concerns, particularly by the Central Arizona Water Conservation District. The Central <br />Arizona Project and Arizona Colorado River entitlement holders with a post September 30, <br />1968 priority date have the lowest priority among Boulder Canyon Project Act Contractors <br />in years of shortage and, therefore, would be impacted by earlier shortage determinations <br />that could be caused by continued bypass of the Wellton-Mohawk Division drainage flows <br />without either operation ofthe YDP or implementation of measures to replace the bypassed <br />drainage water. Accordingly, this report proposes temporary replacement measures that <br />can help address those concerns <br /> <br />Emerl!ence Of Environmental Considerations Associated With Bvvass Drain Flows <br /> <br />When Minute No. 242 and the Colorado River Basin Salinity Control Act were approved in <br />the early 1970's, the Cienega was a tide-washed depression adjacent to the Gulf of <br />California comprised of a few hundred acres of saline marsh. The potential environmental <br />impact ofYDP and other actions approved by the Act was documented in the Colorado <br />River Basin Salinity.Contro1 Project, Title I, Environmental hnpact Statement (EIS) <br />published June 18, 1975 (original EIS). However, the EIS anticipated a period of <br />construction of about 3 years. With the bypass continuing for over 25 years, a wetlands <br />area and habitat of 11,000 acres has established itself. The Cienega has become a complex <br />of open water and tulles providing habitat occupied by migratory waterfowl, shorebirds and <br />other species. <br /> <br />The history of subsequent events and the expansion of wetlands and associated wildlife <br />values resulting from the bypass of Well ton-Mohawk irrigation return water to the Cienega <br />are well known to the natural resource community in the southwest. The area has been <br />designated as a Biosphere Reserve by Mexico under the United Nations Environmental <br />Program. Aspects ofthe environmental and natural science ofthe area have been studied <br />and conclusions on the impacts that would result from cutting offthe current by-pass water <br />from W elton-Mohawk have been reached. It is likely that substantial reduction of current <br />by-pass flows will be met with substantial controversy, additional scientific debate. <br /> <br />The Cienega may be viewed under the President's Council on Environmental Quality <br />(CEQ) guidelines (40 CFRI5029[c][I]), as "significant new circumstances or information> <br />relevant to the environmental concerns that bear on the proposed action or its impacts ". <br />Recognizing this potential, Reclamation proposes to conduct an environmental review, <br />determine the appropriate level of environmental compliance, and initiate development of <br />compliance sufficient to assure operation of the YDP. <br /> <br />een 1/ j ('0 j LV {p..t-\.A i\lh'\. 3D G a-JJ eJ. I dSCUf;:;/;'" i tyc/;r//les -- t)1'/~ <br />14 <br />