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<br />o 0 3 3 ': 3 <br /> <br />As a result it appears fair to assume that the size and extent of the <br />vegetated area of the Cienega is closely related to the quality and quantity of <br />inflows from the MODE and, to a lesser extent, the Riito Drain, with decreases in <br />quality or quantity changing the salinity balance in the lagoon and resulting in <br />corresponding reductions to the vegetated area over time. For example, in early <br />1993 water was cut offto the MODE due to flooding from the Gila River. By <br />July there were gross reduction in vegetated acres of 58% for the lower Cienega <br />and 76% for the upper Cienega compared to November data. Reintroduction of <br />water the following year after repairs to the canal were completed resulted in <br />rapid re-vegetation of both areas. <br /> <br />The brackish wetlands contain populations of two endangered species - <br />Desert Pupfish and Yuma Clapper Rails - and support migratory and wintering <br />waterfowl in the Pacific flyway. Historic fish surveys found populations of <br />endangered desert pupfish in several locations within the Cienega. They were <br />found near the terminus of the MODE, and other locations. The Cienega was <br />found to support potentially the largest population of the Yuma Clapper Rail <br />subspecies throughout its range. The latest survey of Rails in the Cienega was <br />conducted in 1999 and 2000. However, using a conservative estimate, this <br />wetland supports the largest population ofthe subspecies, with probably >70% of <br />all Yuma Clapper Rails in Mexico and the United States. <br /> <br />D. Yuma Desalting Plant (YDP) <br /> <br />The YDP was constructed by the Bureau of Reclamation pursuant to <br />authorization provided by Congress in Title I of the Salinity Control Act Design <br />for the YDP began in June 1977. Construction groundbreaking was in April <br />1980. The Plant was completed and began shakedown testing in December 1991. <br />The YDP operated at one-third capacity for approximately six months in 1992 and <br />1993 before flooding on the Gila River damaged the canals which supply the <br />Plant. <br /> <br />The Bureau <br />conducted an extensive <br />sizing study prior to the <br />design and construction <br />of the Plant. As a result <br />of the study and the <br />successful reduction in <br />return flow from the <br />WMIDD, the YDP as <br />finally constructed has a <br />capacity of 72.4 mgd. <br />The YDP is a reverse <br />osmosis (RO) <br />desalination plant. <br />While there are a <br />variety of commercial <br /> <br /> <br />Recommendations of the YDP/Cienega Workgroup <br /> <br />6 <br />