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A. ENGINEERING-HYDROlOGY 1. Colorado River Salinity Program The Upper Colorado River Commission has continued its interest and involvement in the Colorado River Basin salinity problem. The Commission staff has worked with representatives of the Commission's member States in coordinating and correlating activities with other State and Federal agencies, particularly the Colorado River Basin Salinity Control Forum, which is composed of representatives from the seven Colorado River Basin States. The Forum has developed water quality standards and a plan of implementation to meet the Environmental Protection Agency Regulation (40 CFR Part 120, Water Quality Standards--Colorado River System: Salinity Control Policy and Standards Procedures). Section 303 of the Clean Water Act requires that water quality standards be reviewed from time to time and at least once during each three- year period. The Forum in 2002 reviewed the existing State-adopted and Environmental Protection Agency-approved numeric salinity criteria and found no reason to recommend changes for the three lower mainstem stations. The values are: Salinitv in (mQfI) Below Hoover Dam ... . . . . . . . . . . . . . . . . . . . . . . .. 723 Below Parker Dam ........................... 747 Imperial Dam ......................... . . . . . . . 879 The Forum is now in the midst of its 2005 Review. For several years the states, the Upper Colorado River Commission and the Forum have been working with Reclamation as it attempts to create a river model that can reproduce flows and salinity concentrations of the past and predict probabilities of flows and salinity concentrations in the future. It now appears that this model has been developed sufficiently that it can be used as a tool in the preparation of the 2005 Review. The Salinity Control Program has been successful in implementing controls that have reduced the average concentrations at downstream measuring points by perhaps 80 mg/l. The Forum's goals are based on long-term averages and the river model can assist with the analysis of future salinity control needs. Currently it is felt that about as much salinity control will need to be implemented in the next 1 5 years as have occurred in the last 1 5 years to meet water quality objectives. The Salinity Control Program cannot offset short-term variances caused by short-term hydrologic variances from the norm. The Forum is also concerned that Reclamation has identified that salt has been stored in the lower part of Lake Powell and that now that stored salt may be released to the downstream water supply because of low lake levels that are the result of recent dry years. 8