gly 521- hydrogeology
DESCRIPTION
GLY 521- Hydrogeology. Modflow Packages. Modflow Packages. Block Center Flow (BCF) Package. The BCF package is the central package for all solutions Specify the way each cell will be treated here. Conductance. Recharge Package. One value assigned to each vertical column - PowerPoint PPT PresentationTRANSCRIPT
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GLY 521- Hydrogeology
Modflow Packages
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Modflow Packages
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Block Center Flow (BCF) Package
• The BCF package is the central package for all solutions
• Specify the way each cell will be treated here
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Conductance
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Recharge Package
• One value assigned to each vertical column
• Can assign to uppermost cell or specified layer
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Evapotranspiration Package
• Allows ET only when water table depth is shallow
• Can allow ET only from uppermost cells
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River Package
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River Package
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River Package
Stage above water table
Stage below water table
Water table below bed
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River Package
Note: you want to make sure that the total flux to the stream is preserved at a given head difference. Conductance should be preserved, even if stream geometry is not.
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Stream Package (Prudic 1989)
• Not part of original Modflow
• Routes water through stream segments
• Calculates stage in reaches using channel hydraulics (Manning’s Equation)
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General Head Boundary
boundarymodel cell
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General Head Boundary
• GHB package often used to simulate lakes and reservoirs
• Can also be used to “telescope” a model down to a smaller area
GHB
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General Head Boundary
• Caution! Make sure GHB is does not affect model area
• Can use zone budget to assure water balance
GHB
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Zone Budget
• Not a package, but a separate program
• Specify groups of cells as “zones” and zonebudget calculates water balance on each zone