CRWR Online Report 97-1

Spatial Water Balance of Texas

TABLE OF CONTENTS

• 1. INTRODUCTION
  
• 2. LITERATURE REVIEW
• 2.1 Atmospheric Water Balance Studies
• 2.2 Soil Water Balance Studies
• 2.3 Surface Water Balance Studies
• 2.3.1 Water Balances of Texas
• 2.3.2 Runoff Mapping
  
• 3. ATMOSPHERIC WATER BALANCE
• 3.1 Atmospheric Data
• 3.2 Methodology
• 3.2.1 Water Balance Equations
• 3.2.2 A Control Volume over Texas
• 3.2.3 Direct Computation and Flux Integration Approaches to Estimate Divergence
• 3.2.3.1 Divergence approach
• 3.2.3.2 Flux integration approach
• 3.3 Results and Discussion
• 3.3.1 Results
• 3.3.2 Sources of error
• 3.3.3 Summary and Discussion
  
• 4. SOIL-WATER BALANCE
  
• 4.1 Methodology
• 4.1.1 Model Description
• 4.1.2 Description of input data
• 4.1.2.1 Climate data
• 4.1.2.2 Water-holding capacity data
• 4.1.2.3 Open Water Evaporation Estimates
• 4.1.2.4 Radiation Data
• 4.1.3 Water-holding capacity of the soil
• 4.1.4 Estimating Actual Evapotranspiration
• 4.1.5 Budgeting soil moisture to yield surplus
• 4.1.6 Balancing Soil Moisture
  
• 4.2 Potential Evapotranspiration
• 4.2.1 Potential evaporation vs. potential evapotranspiration
• 4.2.2 Penman combination method
• 4.2.3 Simpler Methods
• 4.2.3.1 Pan coefficients
• 4.2.3.2 Priestley-Taylor Method
• 4.2.3.3 Comparison of Pan and Priestley-Taylor Methods
• 4.3 Results
• 4.4 Summary
  
• 5. SURFACE WATER BALANCE
  
• 5.1 Overview
• 5.2 Methodology
• 5.2.1 Digital Elevation Model Processing
• 5.2.2 Selecting Gaging Stations for Analysis
• 5.2.3 Watershed Delineation
• 5.2.4 Compiling Watershed Attributes
• 5.2.4.1 Determining Mean Precipitation and Net Inflow
• 5.2.4.2 Reservoir Evaporation
• 5.2.4.3 Urban Land Use
• 5.2.4.4 Recharge
• 5.2.4.5 Springs
• 5.3 Results and Discussion
• 5.3.1 Expected Runoff
• 5.3.2 Mapping Actual Runoff and Evaporation
• 5.3.3 Mapping the Bowen Ratio
• 5.3.4 Summary Tables
• 5.3.5 Summary and Discussion
  
• 6. CONCLUSIONS
  
• 7. ACKNOWLEDGEMENT
  
• 8. REFERENCES
  
• 9. APPENDIX