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<br /> <br />w <br />(.0 <br />w <br />..,::. <br /> <br />The plan of implementation is designed to control enough salt to maintain the numeric <br />criteria under a long-tenn mean water supply of 15 million acre-feet per year. It is recognized <br />that the river system is subject to highly vanable flows. Consequently, salinity will vary from <br />year to year ana may temporarily exCeea the adopted numeric cnteria m some years and remain <br />well below the criteria in others. The federal regulation provides for such temporary increases <br />above the numeric criteria. <br /> <br />Should water development projects be completed before control measures are identified <br />or brought on line, temporary increases above the numeric criteria could result. However, these <br />increases will be deemed in conformance with the standards if appropriate salinity control <br />measures are included in the plan. <br /> <br />Increases above the criteria as a result of below nonnal annual river flows and/or low <br />reservoir storage conditions will also be considered in confonnance with the standards, provided <br />that when river flows return to nonnal and satisfactory reservoir conditions prevail, <br />concentrations will be at or below the criteria level. <br /> <br />Current salinity concentrations at the three criteria stations are: <br /> <br />Station <br /> <br />Numeric Criteria 1991 Salinity A(ijusted Salinity <br />in mg/L* Concentration Concentration <br /> in mg/L* in mg/L** <br />723 634 720 <br />747 635 747 <br />879 753 864 <br /> <br />Below Hoover Dam <br />Below Parker Dam <br />Imperial Dam <br /> <br />*Flow-weighted average annual salinity. Observed 1991 salinity levels were low due to unusually high runoffin earlier <br />years and storage of that water in reservoirs. <br /> <br />**Adjusted to reflect salinity that would have occurred with a long-term mean water supply. <br /> <br />Based on the available data, the Forum concludes that the measured salinity will not <br />exceed the numeric criteria during the next three years. With the implementation of the plan, <br />the Forum also concludes that the adjusted salinity concentrations will not exceed the numeric <br />criteria during the next three years. The plan of implementation adopted herein by the Forum <br />provides for the control of about 1,375,000 tons per year (tons/yr) of salt by the year 2015, and <br />the total plan as identified herein will remove about 1,455,700 tons/yr. <br /> <br />The Forum has reviewed the impact of the program on projected salinities and finds that <br />in the year 2015, the plan will control salinity levels so that, with long-tenn mean water supply <br />conditions, salinity levels will be below the numeric criteria at the three stations. The salinity <br />standards provide protection from long-tenn increases in economic damage to downstream users. <br /> <br />Because of the long lead time required to conduct salinity studies; complete <br />environmental and feasibility reports; and authorize, implement, and achieve full salinity <br />reduction effects at the lower main stem stations, continued funding is necessary for the <br /> <br />vii <br />