1. Bacteria and Dissolved Oxygen Total Mass Daily Load Development for the Atascosa River Jessica L. Watts

2. TMDL Overview A TMDL is a tool for implementing state water quality standards. It is based on the relationship between sources of pollutants and in- stream water quality conditions. TMDL = LC = WLA + LA + MOS LA WLAMOS TMDL where: LC = loading capacity WLA = wasteload allocation LA =load allocation; and MOS =margin of safety

3. Natural Water Quality Assessment and Control Priority Ranking and Targeting Assessment of Water Quality-Based Control Actions Identification of Water Quality-Limited Waters Development of TMDLs Implementation of Control Actions Components of TMDL Development 1.Problem Identification 2.Identification of water quality indicators and targets 3.Source assessment 4.Linkage between water quality targets and sources 5.Allocations 6.Follow-up monitoring and evaluation 7.Assembling the TMDL

4. 1. What are the Designated Uses and Associated Impairments of the river? 2. What Data are readily available? 3. What is the Geographic Setting of the TMDL? 4. What are the Exacerbating Characteristics of the river and its watershed? 5. What are the Pollutant Sources and Pathways?  What temporal considerations affect the TMDL?  How will margin of safety be addressed in the TMDL?  What are some potential control options? Key Questions Considered for Problem Identification

5. The Atascosa River’s designated uses  Aquatic Life Subcategory – High Subcategory – High Has NO known Federally Endangered or Threatened Aquatic Species Has NO known Federally Endangered or Threatened Aquatic Species  Contact Recreation  General  Fish Consumption  Public Water Supply Key Question #1: What are the Designated Uses and Associated Impairments of the River?

6. Associated Impairments/ 2004 Concerns US 281 25 Miles Surrounding US 281 Concerns  C ontact Recreation Use  B acteria  N utrient Enrichment Concern  A mmonia  A lgal Growth Concern  E xcessive Algal Growth  P ublic Water Supply  Total Dissolved Solids Lower 25 Miles Concerns PPPPublic Water Supply otal Dissolved Solids Remainder of Segment Concerns  Public  Public Water Supply  Total Dissolved Solids

7. Readily Available Information Information was downloaded from the web, including:  EPA Basins: River Reaches River Reaches Soil Information (STATSGO) Soil Information (STATSGO) Major Roads Major Roads HUC Boundary HUC Boundary Dam Sites Dam Sites Counties Counties Ecoregions Ecoregions Water Quality Monitoring Station Summaries Water Quality Monitoring Station Summaries Bacteria Monitoring Station Summaries Bacteria Monitoring Station Summaries Weather Station Sites Weather Station Sites USGS Gaging Stations USGS Gaging Stations Clean Water Needs Survey Clean Water Needs Survey Industrial Facilities Discharge Sites Industrial Facilities Discharge Sites Permit Compliance System Sites and Loadings Permit Compliance System Sites and Loadings CERCLIS – Superfund National Priority List CERCLIS – Superfund National Priority List RCRIS – Resource Conservation and Recovery Information Systems RCRIS – Resource Conservation and Recovery Information Systems Mineral Industry Locations Mineral Industry Locations  USGS Seamless: Aquifers National Elevation Dataset 1992 Land Use  USGS – NHD: Points Wells Gaging Stations Flowlines Waterbodies  PRISM Precipitation Key Question #2: What Data are readily Available?

8. Geographic Setting of the Atascosa River Key Question #3: What is the Geographic Setting of the TMDL?

9. Land Use Key Question #4: What are the Exacerbating Characteristics of the river and its watershed?

10. Point Source Pollutant Sources Legend 1 CERCLIS - Superfund 6 NPDES 11Industrial Facilities Discharge 40Mineral Industry Key Question #5: What are the Pollutant Sources and Pathways?

11. Pollutant Pathways Use of GIS in Pollutant Transport Modeling

12. How GIS Fits Into BASINS & the TMDL Process Meteorological Data GIS Landuse and pollutant specific Data HSPF Landuse Distribution Stream Data Point Sources Core Model Post Processing Windows interface Landscape data ABDEFC CH2MHILL

13. Atascosa DEM Terrain Processing

14. Atascosa Subwatershed Creation 33 Catchments2 Gaging Stations and 1Outlet _____________________ 36 Subwatersheds Used a Threshold of 60 to create

15. What’s Next  BASINS Predefined Delineation Process Shapefiles and Tables Shapefiles and Tables SubbasinsSubbasins StreamsStreams OutletOutlet

16. Questions? Picture by: James Hindes http://www.pbase.com/jhindes/the_river Acknowledgements Dr. David Maidment Nate Johnson Carrie Gibson