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Long Hollow Dam and Reservoir Phase I Summary Report <br /> water quality standards may not currently be exceeded very often, if at all. The Water Quality <br /> Control Commission will be involved in assessing any potential water quality impacts from the <br /> LHR project through the CWA Section 401 certification process. <br /> WWE also completed independent evaluation of the potential for impacts to water quality from <br /> the LHR project (WWE, February 2004). The water quality impact assessment completed for the <br /> ALP Project and the WWE analysis both found that the LHR project should not adversely affect <br /> water quality in the La Plata River basin. No new land will be irrigated under LHR. LHR will <br /> provide supplemental irrigation water only for land that has been irrigated for more than 80 <br /> years. Studies completed for the ALP project found that selenium and other metals have been <br /> leached from the soil so that their future concentrations in return flows should not be excessive or <br /> pose a risk to the water quality of receiving streams. The water exchanged for irrigation with <br /> LHR Compact releases will be diverted upstream where concentrations of selenium and other <br /> metals are lower. Return flows will accrue to the lower river where concentrations are higher <br /> (see Table 4). In addition, the quantity of return flows will be relatively small compared to the <br /> flow in the river. The effect on concentrations of metals and other minerals from LHR <br /> evaporation will be minimal since the amount of evaporation will be relatively small. <br /> As a result, concentrations of selenium and other metals in the La Plata River will not be <br /> increased by the project, and could decrease slightly or remain at pre-project levels. No <br /> significant changes in the frequency or duration of water quality standards exceedences will <br /> result from the project. Therefore, no adverse impacts on aquatic life because of LHR-caused <br /> water quality changes should occur. <br /> 8.0 RESERVOIR OPERATIONS, RIGHTS-OF-WAY, COST AND FINANCING <br /> 8.1 Water Allocation and Reservoir Operations <br /> WWE used a water allocation model (MODSIM) to simulate flow in and diversions from the La <br /> Plata River under both pre- and post-LHR conditions for the 14 years from WY 1989 through <br /> WY 2002. This study period was selected because of the availability of flow data from five <br /> 991-077.115 Wright Water Engineers, Inc. Page 17 <br /> July 2004 <br />