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South Y PCE_Feb-19_TAC_021919_SR_small
SCENARIOS 1A &1B: BASELINE AND CONSERVATIVE BASELINE•Scenario 1A Baseline represents calibrated model results•Scenario 1B Conservative Baseline adds a continuous recharge concentration of 10 mg/l for the duration of the model and removes all biodegradation•Each management scenario is run under both conditions, and results are compared to the respective baseline result 2018 BASELINE/CONSERVATIVE RESULTSScenario 1A, 2018 stress period, layer 1 Scenario 1B, 2018 stress period, layer 1Mass within contours≥ 100 ug/l: 142.5 kg50 - 100 ug/l: 139.8 kg10 – 50 ug/l: 103.8 kg5-10 ug/l: 12.1 kg1-5 ug/l: 8.5 kg0.5-1 ug/l: 0.98 kgTotal mass layer 1: 407.7 kg Mass within contours≥ 100 ug/l: 1429.5 kg50 - 100 ug/l: 137.5 kg10 – 50 ug/l: 94.6 kg5-10 ug/l: 10.3 kg1-5 ug/l: 7.6 kg0.5-1 ug/l: 0.85 kgTotal mass layer 1: 1680.3 kg 2018 BASELINE/CONSERVATIVE RESULTSScenario 1A, 2018 stress period, layer 2 Scenario 1B, 2018 stress period, layer 2Mass within contours10 – 50 ug/l: 25.1 kg5-10 ug/l: 12.3 kg1-5 ug/l: 8.2 kg0.5-1 ug/l: 1.1 kgTotal mass layer 2: 46.7 kg Mass within contours≥ 100 ug/l: 1153.3 kg50 - 100 ug/l: 124.5 kg10 – 50 ug/l: 85.9 kg5-10 ug/l: 9.5 kg1-5 ug/l: 7.5 kg0.5-1 ug/l: 0.83 kgTotal mass layer 2: 1381.5 kg 2018 BASELINE/CONSERVATIVE RESULTSScenario 1A, 2018 stress period, layer 3 Scenario 1B, 2018 stress period, layer 3Mass within contours1-5 ug/l: 4.4 kg0.5-1 ug/l: 1.4 kgTotal mass layer 3: 5.8 kg Mass within contours≥ 100 ug/l: 228.5 kg50 - 100 ug/l: 303.2 kg10 – 50 ug/l: 231.0 kg5-10 ug/l: 25.6 kg1-5 ug/l: 18.1 kg0.5-1 ug/l: 2.3 kgTotal mass layer 3: 808.6 kg 2018 BASELINE/CONSERVATIVE RESULTSScenario 1A, 2018 stress period, layer 4 Scenario 1B, 2018 stress period, layer 4Total mass layer 4: 0 kg Mass within contours10 – 50 ug/l: 51.2 kg5-10 ug/l: 12.2 kg1-5 ug/l: 8.4 kg0.5-1 ug/l: 0.93 kgTotal mass layer 4: 72.7 kg SCENARIOS 1A & 1B: BASELINE & CONSERVATIVE BASELINEScenario 1A, 2038 stress period, layer 1Scenario 1B, 2038 stress period, layer 1 SCENARIOS 1A & 1B: BASELINE & CONSERVATIVE BASELINEScenario 1A, 2038 stress period, layer 2Scenario 1B, 2038 stress period, layer 2 SCENARIOS 1A & 1B: BASELINE & CONSERVATIVE BASELINEScenario 1B, 2038 stress period, layer 3Scenario 1A, 2038 stress period, layer 3 SCENARIOS 1A & 1B: BASELINE & CONSERVATIVE BASELINEScenario 1B, 2038 stress period, layer 4Scenario 1A, 2038 stress period, layer 4 SCENARIOS 1A & 1B: BASELINE & CONSERVATIVE BASELINE BREAKTHROUGH CURVES01020304050607080901001971 1985 1999 2012 2026 2040 2053 2067PCE (ug/l)TKWC 1Baseline (1A)Conservative Baseline (1B)Observed0501001502002503003504001971 1985 1999 2012 2026 2040 2053 2067PCE (ug/l)TKWC 2Baseline (1A)Conservative Baseline (1B)Observed00.0050.010.0150.020.0250.030.0350.040.0451971 1985 1999 2012 2026 2040 2053 2067PCE (ug/l)TKWC 3Baseline (1A)Conservative Baseline (1B)Observed 0204060801001201401971 1985 1999 2012 2026 2040 2053 2067PCE (ug/l)LBWC 5Baseline (1A)Conservative Baseline (1B)Observed00.10.20.30.40.50.61971 1985 1999 2012 2026 2040 2053 2067PCE (ug/l)LBWC 1Baseline (1A)Conservative Baseline (1B)ObservedSCENARIOS 1A & 1B: BASELINE & CONSERVATIVE BASELINE BREAKTHROUGH CURVES SCENARIOS 1A & 1B: BASELINE & CONSERVATIVE BASELINE SUMMARY/CONCLUSIONS•Neither baseline scenario shows PCE above detection limits at LBWC 1 or TKWC 3 at any time; analysis limited to LBWC 5 and TKWC 1&2•Baseline (1A) is generally more representative of observed concentrations with the exception of late time at LBWC 5, located at edge of plume•Both conditions assessed for all management scenarios to provide conservative bookend SCENARIOS 2A & 2B: EXTRACTION WELLS•Row of 21 extraction wells placed in layer 1, each well pumping at 40 gpm•All production wells pumping at baseline rates•Scenario 2A run under baseline conditions; Scenario 2B run under conservative conditions SCENARIO 2A: EXTRACTION WELLSScenario 1A, 2038 stress period, layer 1Scenario 2A, 2038 stress period, layer 1 SCENARIO 2A: EXTRACTION WELLSScenario 1A, 2038 stress period, layer 2Scenario 2A, 2038 stress period, layer 2 SCENARIO 2A: EXTRACTION WELL BREAKTHROUGH CURVES0.00.51.01.52.02017 2031 2045 2058PCE (ug/l)TKWC 1BaselineScenario 2A012345672017 2031 2045 2058PCE (ug/l)LBWC 5BaselineScenario 2A0246810121416182017 2031 2045 2058PCE (ug/l)TKWC 2BaselineScenario 2AWellBaselineYear PCE below 4 ug/lScenario 2AYear PCE below 4 ug/lLBWC 5 2025 2023TKWC 1 N/A N/ATKWC 2 2039 2040 SCENARIO 2B: CONSERVATIVE EXTRACTION WELLSScenario 1B, 2038 stress period, layer 1Scenario 2B, 2038 stress period, layer 1 SCENARIO 2B: CONSERVATIVE EXTRACTION WELLSScenario 1B, 2038 stress period, layer 2Scenario 2B, 2038 stress period, layer 2 SCENARIO 2B: CONSERVATIVE EXTRACTION WELLSScenario 1B, 2038 stress period, layer 3Scenario 2B, 2038 stress period, layer 3 SCENARIO 2B: CONSERVATIVE EXTRACTION WELLSScenario 1B, 2038 stress period, layer 4Scenario 2B, 2038 stress period, layer 4 SCENARIO 2B: CONSERVATIVE EXTRACTION WELL BREAKTHROUGH CURVES0204060801001201402017 2031 2045 2058PCE (ug/l)LBWC 5Scenario 2AScenario 2BScenario 2B baseline0204060801002017 2031 2045 2058PCE (ug/l)TKWC 1Scenario 2AScenario 2BScenario 2B baseline0501001502002503003504002017 2031 2045 2058PCE (ug/l)TKWC 2Scenario 2AScenario 2BScenario 2B baselineWellConservative BaselineYear PCE below 4 ug/lScenario 2BYear PCE below 4 ug/lLBWC 5 2047 2052TKWC 1 >2068 >2068TKWC 2 >2068 >2068 SCENARIO 2A & 2B: EXTRACTION WELLS SUMMARY/CONCLUSIONS•Approximately 135 kg of mass is removed by extraction wells and 113 kg of mass is removed by production wells in the under baseline conditions•Approximately 552 kg of mass is removed by extraction wells and 2961 kg of mass is removed by production wells under conservative conditions•Declines in concentrations at production wells are minimal as extraction wells tend to retard plume migration SCENARIO 4B & 4C: REPLACEMENT WELLS RW-D & RW-F•TKWC 2 pumping moved to RW-D•Half of LBWC 5 pumping moved to RW-F•All other production wells pumped at baseline rates•Scenario 4B run under baseline conditions; Scenario 4C run under conservative conditions SCENARIO 4B: REPLACEMENT WELLS, RW-D & RW-FScenario 4B, 2038 stress period, layer 1Scenario 1A, 2038 stress period, layer 1 SCENARIO 4B: REPLACEMENT WELLS, RW-D & RW-FScenario 4B, 2038 stress period, layer 2Scenario 1A, 2038 stress period, layer 2 SCENARIO 4B: REPLACEMENT WELLS BREAKTHROUGH CURVES012345672017 2031 2045 2058PCE (ug/l)LBWC 5BaselineScenario 4B0.00.51.01.52.02017 2031 2045 2058PCE (ug/l)TKWC 1BaselineScenario 4B0246810121416182017 2031 2045 2058PCE (ug/l)TKWC 2BaselineScenario 4BWellBaselineYear PCE below 4 ug/lScenario 4BYear PCE below 4 ug/lLBWC 5 2025 2022TKWC 1 N/A N/ATKWC 2 2039 2038 SCENARIO 4C: CONSERVATIVE REPLACEMENT WELLS, RW-D & RW-FScenario 1B, 2038 stress period, layer 1Scenario 4C, 2038 stress period, layer 1 SCENARIO 4C: CONSERVATIVE REPLACEMENT WELLS, RW-D & RW-FScenario 1B, 2038 stress period, layer 2Scenario 4C, 2038 stress period, layer 2 SCENARIO 4C: CONSERVATIVE REPLACEMENT WELLS, RW-D & RW-FScenario 1B, 2038 stress period, layer 3Scenario 4C, 2038 stress period, layer 3 SCENARIO 4C: CONSERVATIVE REPLACEMENT WELLS, RW-D & RW-FScenario 1B, 2038 stress period, layer 4Scenario 4C, 2038 stress period, layer 4 SCENARIO 4C: CONSERVATIVE REPLACEMENT WELLS BREAKTHROUGH CURVES0204060801001201402017 2031 2045 2058PCE (ug/l)LBWC 5Conservative Baseline (1B)Scenario 4BScenario 4C0204060801001201401601802017 2031 2045 2058PCE (ug/l)TKWC 1Conservative Baseline (1B)Scenario 4BScenario 4C0501001502002503003504002017 2031 2045 2058PCE (ug/l)TKWC 2Conservative Baseline (1B)Scenario 4BScenario 4CWellConservative BaselineYear PCE below 4 ug/lScenario 4CYear PCE below 4 ug/lLBWC 5 2047 2045TKWC 1 >2068 >2068TKWC 2 >2068 >2068 SCENARIO 4B & 4C: REPLACEMENT WELLS SUMMARY/CONCLUSIONS•Little effect on PCE concentrations in TKWC 2 and LBWC 5.•Decrease in concentrations in TKWC 1 under baseline conditions.•Increase in concentrations in TKWC 1 under conservative conditions – simulated mass exists in model layer 3, where replacement wells are pumping. Plume migration is retarded and pulled east.•PCE in RW-D approaches MCL under conservative conditions. SCENARIO 5A & 5B: MAX SUPPLY WELL PUMPING•Pumping increased at LBWC 5 and TKWC 2; to be treated on-site•Pumping decreased at nearby STPUD wells; to be replaced by treated water•Pumping at TKWC 1, TKWC 3, and LBWC 1 remains at baseline rate SCENARIO 5A: MAX SUPPLY WELL PUMPINGScenario 5A, 2038 stress period, layer 1Scenario 1A, 2038 stress period, layer 1 SCENARIO 5A: MAX SUPPLY WELL PUMPINGScenario 5A, 2038 stress period, layer 2Scenario 1A, 2038 stress period, layer 2 SCENARIO 5A: MAX SUPPLY WELL PUMPING BREAKTHROUGH CURVES02468102017 2031 2045 2058PCE (ug/l)LBWC 5BaselineScenario 5A0.00.51.01.52.02017 2031 2045 2058PCE (ug/l)TKWC 1BaselineScenario 5A05101520252017 2031 2045 2058PCE (ug/l)TKWC 2BaselineScenario 5AWellBaselineYear PCE below 4 ug/lScenario 5AYear PCE below 4 ug/lLBWC 5 2025 2028TKWC 1 N/A N/ATKWC 2 2039 2035 SCENARIO 5B: CONSERVATIVE MAX SUPPLY WELL PUMPINGScenario 5B, 2038 stress period, layer 1Scenario 1B, 2038 stress period, layer 1 SCENARIO 5B: CONSERVATIVE MAX SUPPLY WELL PUMPINGScenario 5B, 2038 stress period, layer 2Scenario 1B, 2038 stress period, layer 2 SCENARIO 5B: CONSERVATIVE MAX SUPPLY WELL PUMPINGScenario 5B, 2038 stress period, layer 3Scenario 1B, 2038 stress period, layer 3 SCENARIO 5B: CONSERVATIVE MAX SUPPLY WELL PUMPINGScenario 5B, 2038 stress period, layer 4Scenario 1B, 2038 stress period, layer 4 SCENARIO 5B: CONSERVATIVE MAX SUPPLY WELL PUMPING BREAKTHROUGH CURVES0204060801001201402017 2031 2045 2058PCE (ug/l)LBWC 5Conservative Baseline (1B)Scenario 5AScenario 5B0204060801002017 2031 2045 2058PCE (ug/l)TKWC 1Conservative Baseline (1B)Scenario 5AScenario 5B0501001502002503003504002017 2031 2045 2058PCE (ug/l)TKWC 2Conservative Baseline (1B)Scenario 5AScenario 5BWellConservative BaselineYear PCE below 4 ug/lScenario 5BYear PCE below 4 ug/lLBWC 5 2047 2044TKWC 1 >2068 2060TKWC 2 >2068 2064 MASS REMOVAL COMPARISON – EXTRACTION WELLS (2A&2B) VS MAX SUPPLY WELL PUMPING (5A&5B)012345672018 2021 2024 2026 2029 2032 2035 2037Mass removed (kg)LBWC 5Scenario 2AScenario 5A0246810122018 2021 2024 2026 2029 2032 2035 2037Mass removed (kg)TKWC 2Scenario 2AScenario 5ABaseline010203040506070802018 2021 2024 2026 2029 2032 2035 2037Mass removed (kg)LBWC 5Scenario 2BScenario 5B0501001502002018 2021 2024 2026 2029 2032 2035 2037Mass removed (kg)TKWC 2Scenario 2BScenario 5BConservative MAX SUPPLY WELL PUMPING SUMMARY/CONCLUSIONS•Greatest amount of mass extraction over all scenarios (330 kg baseline/4872 kg conservative)•Increased pumping at LBWC 5 & TKWC 2 tends to protect downgradient TKWC 1, reducing concentration at that well•Only conservative scenario showing concentrations below MCL at TKWC 1 & 2 before end of simulated time period (2068).