1. Watershed Management Decision Support Using Web-Based Hydrological Tools and GIS Bernard A. Engel Jin-Yong Choi Larry Theller Agricultural and Biological Department Purdue University

2. Processes for Hydrologic Impact Analysis Using Web-GIS Tools Outlet Point Selection Using Web-GIS Run Watershed Delineation Watershed Delineation Result Reflect Land Use Change Using Online Digitizing Run L-THIA Runoff and NPS Output/Impact Evaluation

3. Front Page

4. Select Outlet Point Main Menu Layer Control On/Off Map Display Display Control Zoom in/out Pan, Full extent Auxiliary functions Reference Map WD Submit Button

5. Watershed Delineation and Result Page

6. Results Display

7. Print and Download Page

8. L-THIA Input Data Preparation for Present Land Use and Hydrologic Soil Group

9. Buttons for Online Tool

10. Change Land Use in the Watershed Using Online Digitizing Tool Add Low Density Residential, Commercial, and High Density Residential Areas

11. Results Page after the Land Use Change Present Land Use Data Proposed Land Use Data Application Buttons for Hydrological Model Operation

12. L-THIA Input Page After Changing Land Use

13. L-THIA Results - Runoff Tables

14. Runoff and Land Use to Evaluate the Land Use Change Impact on Hydrology

15. NPS Pollutant Loading