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<br />Nutrients <br /> <br />Nutrients could be addressed in a stepwise approach. The first step would build on the <br />information dcvcloped for the metals analysis. Flux rates for nutrients (e.g., phosphorus <br />and nitrogen) would be established through the available literature and the concentrations <br />in the surface water determined would be based on the size of the anoxic zone. Dissolved <br />oxygen (DO) values in the water column could not be determined but assumptions could <br />be made based on the size of the existing anoxic zone and that of the reservoir under <br />reallocation. <br /> <br />Assumption: The only thing that changes between the current and future scenarios is the <br />size of the anoxic zone and the lake volume. <br /> <br />Limitations: As with the metals approach, this approach does not fully address the <br />dynamics of the system. It does, however, evaluate the most probable mechanism for <br />nutrient influences (and ultimately eutrophication) under the proposed scenario. Algae <br />would not be addressed but potential issues could be inferred based on the results of the <br />nutrient analysis. <br /> <br />Cost: Approximately $3,000 <br /> <br />If the results of the first step above determined that there was a likelihood ofa significant <br />increase in nutrient concentrations or concerns relating to DO, the second step would be <br />to use the LAKE2K model. The model would be configured and calibrated using <br />existing data. Tetra Tech would then run a Monte Carlo simulation to evaluate the <br />impact of different anoxic bottom volumes on the system. Rather than assuming one rate, <br />we would essentially predict what would happen over a range of conditions - to <br />"bracket" possible influences. This approach uses a statistically-based approach, <br />therefore we could essentially characterize the likelihood of improved conditions versus <br />worsened conditions. This approach would allow for the evaluation of algae, nutrients <br />and DO. <br /> <br />Assumptions: The only real mechanisms affecting the system are an increase in volume <br />accompanied by an increased anoxic bottom volume. <br /> <br />Limitations: No detailed operations, hydrodynamics, etc. would be considered. <br /> <br />Cost: $50,000-$60,000 <br />