2010-10-22_PERMIT FILE - M2010071 (3)

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sections including "Flow Boundary Conditions" and "Transport Boundary Conditions." This study is for ground water flow and not transports evaluation; therefore, the "Flow Boundary Conditions" was selected. The set of boundary conditions for the study was considered included the following: • Constant Head (CHD) Boundary Conditions • River (RIV) Boundary Conditions • Stream (STR) Boundary Conditions • General-Head (GHB) Boundary Conditions • Drain (DRN) Boundary Conditions • Wall (HFB) Boundary Conditions • Step 2 Recharge (RCH) Boundary Conditions • Evapotranspiration (EVT) Boundary Conditions The Horizontal-Flow-Barrier (HFB) package, or Wall Boundary Conditions as it is referred to in Visual MODFLOW, was developed to simulate thin, vertical, low- permeability features that impede the horizontal flow of ground water. CTL I T entered Wall Boundary Conditions around the approximate perimeter of the existing reservoirs to simulate the lining of the existing reservoirs. A hydraulic conductivity of 1 x 10-6 cm/s (0.0028 ft/day) was assigned for the Wall Boundary Conditions which was based upon typical values of compacted clay liners with similar soil classification and measured soil properties. The Constant Head Boundary Conditions are used to fix the head value in selected grid cells regardless of the system conditions in the surrounding grid cells, thus acting as an infinite source of water entering the system, or as an infinite sink for water leaving the system. Constant Head Boundary Conditions were assigned to the model cells in each of the existing reservoirs to simulate the normal high-water elevations controlled in each of the existing reservoirs. A constant head of 5,043.5 feet was used for Goose Haven Reservoir No. 1 and a constant head of 5,050 feet was used for Goose Haven Reservoir No. 3. It is understood that these elevations are the normal high-water elevations for the respective reservoirs. • McLAUGHLIN WATER ENGINEERS, LTD. 9 GOOSE HAVEN RESERVOIR COMPLEX EXPANSION CTL i T PROJECT NO. FC04797.002-145