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DocuSign Envelope ID: EBE28081-13782-41342-BAD13-D8C9313687131B <br />TOXICITY REDUCTION EVALUATION — LINES OF INVESTIGATION <br />Design Basis <br />�.0 DESIGN BASIS <br />2.1 INFLUENT WATER QUALITY <br />The flow at Outfall 010 is measured by a 30-inch Parshall Flume located at the discharge. This reading is <br />correlated to a specific flowrate which has been measured and correlated to a monthly flow profile. East <br />Taylor Pond currently receives seep and surface runoff from a series of channels around the reclaimed <br />areas to the south and east. This combined water quality data shows elevated alkalinity, TDS, sulfate, <br />sodium, and sodium adsorption ratio (SAR) levels. <br />Testing performed by the SeaCrest Group has shown that lime softening treatment is ineffective in <br />lowering reproductive toxicity levels which suggests that alkalinity and SAR are not the primary <br />constituents of concern (COCs) for the WET of Outfall 010 discharge (SeaCrest 2019). Treatment testing <br />for sulfate, TDS, and sodium using reverse osmosis resulted in a reduction in all forms of chronic toxicity. <br />The determined water quality considered for the design evaluations is outlined in Table 1 - Outfall 010 <br />Water Quality (SeaCrest 2019). This table is a compilation of average concentrations observed during <br />the period of increasing outfall volumes. Flow and sulfate concentrations are reflective of additional <br />analysis. <br />Table 1 - Outfall 010 Water Quality Basis <br />Parameter <br />Units <br />TIE (July) <br />Parameter <br />Units <br />TIE (July) <br />Flow <br />gpm <br />364 <br />SAR <br />17.2 <br />pH <br />s.u. <br />8.29 <br />Arsenic <br />mg/L <br />1 <br />Conductivity <br />µS/L <br />3,890 <br />Iron <br />mg/L <br />54 <br />Bicarbonate <br />mg/L <br />1,146 <br />Zinc <br />mg/L <br />5.2 <br />TDS <br />mg/L <br />3,330 <br />Silver <br />mg/L <br /><0.5 <br />Sulfate <br />mg/L <br />1,500 <br />Copper <br />mg/L <br />1.2 <br />TSS <br />mg/L <br /><0.1 <br />Cadmium <br />mg/L <br /><0.5 <br />Calcium <br />mg/L <br />140 <br />Chromium <br />mg/L <br /><20 <br />Magnesium <br />mg/L <br />120 <br />Manganese <br />mg/L <br />210 <br />Sodium <br />mg/L <br />810 <br />Selenium <br />mg/L <br /><1 <br />Source contributions to the overall discharge from surface water and seeps have not been specifically <br />investigated. Historical reporting data from East Taylor Pond tracks concentrations at various seasonal <br />flows, (see Figure 1 - Outfall 010: Flow and Sulfate Concentrations) providing additional insight into <br />the water quality design parameters. These data show that higher flows can develop during late winter <br />dpg \\us0321-ppfss011shared_projectsV33001407\reports\4_tre lines of investigationitre lines of investigation_20200320_ifra.docx 2.2 <br />