Technical Comparison of Southern and Central CarrizoWilcox Groundwater Availability Models GAMs in O

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Technical Comparison ofSouthern and Central
Carrizo-WilcoxGroundwater Availability Models
(GAMs) in Overlap Area

• Dave ORourke
• July 8, 2003

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Existing Model Domains
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Existing Model Layer Schemes
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Central C-W GAM Model Outcrop Areas and Recharge
Rates
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Southern C-W GAM Model Outcrop Areas and Recharge
Rates
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Central and Southern C-W GAM Overlap Area Average
Steady-State Recharge Estimates
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Carrizo Formation Horizontal Hydraulic
Conductivity Maps (ft/day)
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Hydraulic Conductivity Anistropy Ratios1 (Kh/Kv)
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Carrizo Formation Thickness Maps (ft)
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Carrizo Formation Transmissivity Maps (gpd/ft)
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Horizontal Flow Barriers
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Year 2050 Predictive Drawdown without SAWS Pumpage
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Year 2050 Predictive Drawdowns with SAWS 25,000
acft/yr
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MW-Nixon Hydrographs
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Year 2050 Water Budgets for GAM Overlap Areas
without SAWS Pumpage
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Water Budget Summary
Values in acre-feet/year
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Water Budget Assessment

• Queen City recharge in Southern C-W GAM appears
  high
• Carrizo recharge in Southern C-W GAM appears low
• Vertical flow into Carrizo in Southern C-W GAM
  appears high
• Stream interaction across entire C-W outcrop is
  approximately equal in both models, but is
  located in different model layers

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Year 2050 Water Budgets for GAM Overlap Areas
with SAWS Pumpage
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Carrizo Aquifer Water Budget Changes with SAWS
Pumpage