SPATIAL WATER BALANCE OF TEXAS
Seann Reed
David Maidment
Jérôme Patoux

Center for Research in Water Resources
University of Texas at Austin
3/6/97
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