1. Non-Point Source Pollutant Modeling Analysis and Prediction David Munn

2. Non-Point Source Pollution Does not come from a single source Results from pollutants being washed out of large areas during storms Difficult to model without use of GIS or current NPSP models

3. Goals Predicting pollutant runoff loads Defining problem areas within the Watershed Determine what factors effect pollutant loading Determine streams with highest impact Pollutants considered: BOD Suspended Solids Total Phosphorous Total Nitrogen

4. Study Area Brazos County Buffered boundary

5. Process Overview Gather data Data preparation Reproject grids and shapefiles Clip themes and set analysis extents Calculate curve numbers Delineate watersheds Calculate pollutant contribution Determine weighted accumulation Analyze data

6. Data/Themes DEM TNRIS Soil Classification STATSGO County Boundaries ESRI, Tiger files Land Use/Land Cover Txdata, Provided by Dr. Olivera Precipitation Txdata, Annual and Monthly LULC Pollutant Contribution Data Cornell University Hydraulics Study

7. Reprojecting Reprojected grids using ArcInfo-Workstation Reprojected geographic shapefiles using CRWR-Vector Data Already in a Projection was reprojected using ArcCatalog Final Projection: State Plane 1927 Central Texas, Zone 5376 Units = feet

8. Delineating Watersheds CRWR-Prepro Burned in Streams Filled Sinks Determined Flow Direction Determined Flow Accumulation Defined Streams Segmented Streams Defined Outlets Delineated Watersheds Vectorized Grids

9. Curve Numbers Used to determine runoff STATSGO data spatially documents soil types (component makeup) Scripts provided by CVEN 689 Website Soilgrp script – calculates % of hydrologic groups per soil type cn script – creates curve numbers based on soil composition

10. Run-off Rainfall given per month (January) Calculate Run-off (mm) using SCS method Map Calculator combined formulas with rainfall and CN Created new grid giving run-off depth per cell

11. Pollutant Contributions Q (mm) Pollutant Concentration (mg/l) Cell size (ft 2 ) = Mass (mg) * Map Calculator

12. Pollutant Flow/Accumulation Weighted flow accumulation Executed in ArcInfo Assigns weights to cells based on a Grid.51.0 2.0 1.0.5 1.0.75 1.5.5 1.0.5 1.0.751.0.5 WeightsDirectionAccumulation

13. Analysis Determine what land-uses and soil types contribute the largest amount of pollutants Determine what rivers suffer the greatest impact Locate areas that contribute large masses of pollutants

14. Land Use Relationships (Zonal Summaries)

15. Soil Type Relationships (Zonal Summaries)

16. Impacted Rivers Method Map query Changed to shapefile Results too dependent on general accumulation More statistical work needed

17. * BOD / SS* TP / TN Areas of Concern

18. Conclusions Urban areas contributed the largest mass of BOD and suspended solids per unit area Agricultural areas contributed the largest mass of Nitrogen and Phosphorous / area Rivers > 700,000 cell accumulation were impacted Soil types differed in impact between pollutants Nutrients: Crocket-Luling-Benchley & Zack-Zulch-Booneville BOD and Suspended Solids Zack-Zulch-Booneville

19. Future Applications Determining Pollutant Concentrations Calculate run-off volume using weighted accumulation Sum run-off volumes with base flows Calculate in-stream concentrations Better Statistical Analyis of Impacted Rivers

20. Problems REPROJECTING!!!!!!! Calculating pollutant contributions (map calculator) Floating point analysis

21. QUESTIONS What up?