1. Water Quality Modeling in GIS Application of Schematic Network Processing Schema Links and Nodes have unique behaviors based on their type A framework for unifying watershed, stream, and estuary models

2. Two Case Studies Galveston Bay Bacteria Study –Application of Model Builder (Arc Toolbox 9.0) Guadalupe River Nitrogen Study –Application of SPARROW for load estimation

3. Galveston Bay

4. Model Builder

5. Rainfall to Runoff

6. Rainfall to Runoff (1 of 2)

7. Rainfall to Runoff (2 of 2)

8. EMC Grid

9. Load Grid

10. Zonal Statistics

11. Process the Schematic Network

12. Results

13. SPARROW Regional-scale statistical water-quality model Developed by USGS Estimates load of pollutant for each sub watershed within a monitored basin using SAS Has been applied to continental US, Mississippi Basin, and Northeastern US

14. 414 National Stream Quality Accounting Network (NASQAN) Stream Monitoring Locations

15. The Guadalupe River at Victoria Texas Basin Red represents along stream flow Green represents land to channel flow

16. Land Surface Load = 100 kg/yr Upstream Load = 50 kg/yr Load = 50 x d channel +100 x d surface d channel = decay due to travel along river channel transport d surface = decay due to land surface to river channel transport Schematic Network Processing Algorithm

17. Nitrogen Load Predictions

18. Comparison with SPARROW Published Results

19. 1:500,000 1:24,000 Future Direction: Improve Data Resolution