Bacteria and Dissolved Oxygen Total Mass Daily Load Development for the Atascosa River

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Bacteria and Dissolved OxygenTotal Mass Daily
Load Developmentfor theAtascosa River

• Jessica L. Watts

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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

TMDL
where LC loading capacity WLA wasteload
allocation LA load allocation and MOS margin
of safety
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Natural Water QualityAssessment and Control
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Key Questions Considered for Problem
Identification

• What are the Designated Uses and Associated
  Impairments of the river?
• What Data are readily available?
• What is the Geographic Setting of the TMDL?
• What are the Exacerbating Characteristics of the
  river and its watershed?
• 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?

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The Atascosa Riversdesignated uses
Key Question 1 What are the Designated Uses
and Associated Impairments of the River?

• Aquatic Life
• Subcategory High
• Has NO known Federally Endangered or Threatened
  Aquatic Species
• Contact Recreation
• General
• Fish Consumption
• Public Water Supply

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Associated Impairments/2004 Concerns

• 25 Miles Surrounding US 281
• Concerns
• Contact Recreation Use
• Bacteria
• Nutrient Enrichment Concern
• Ammonia
• Algal Growth Concern
• Excessive Algal Growth
• Public Water Supply
• Total Dissolved Solids

US 281

• Lower 25 Miles
• Concerns
• Public Water Supply
• Total Dissolved Solids

• Remainder of Segment
• Concerns
• Public Water Supply
• Total Dissolved Solids

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Readily Available Information
Key Question 2 What Data are readily Available?

• Information was downloaded from the web,
  including
• EPA Basins
• River Reaches
• Soil Information (STATSGO)
• Major Roads
• HUC Boundary
• Dam Sites
• Counties
• Ecoregions
• Water Quality Monitoring Station Summaries
• Bacteria Monitoring Station Summaries
• Weather Station Sites
• USGS Gaging Stations
• Clean Water Needs Survey
• Industrial Facilities Discharge Sites
• Permit Compliance System Sites and Loadings
• CERCLIS Superfund National Priority List
• RCRIS Resource Conservation and Recovery
  Information Systems

• USGS Seamless
• Aquifers
• National Elevation Dataset
• 1992 Land Use
• USGS NHD
• Points
• Wells
• Gaging Stations
• Flowlines
• Waterbodies
• PRISM
• Precipitation

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Geographic Settingof theAtascosa River
Key Question 3 What is the Geographic Setting
of the TMDL?
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Land Use
Key Question 4 What are the Exacerbating
Characteristics of the river and its watershed?
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Point Source Pollutant Sources
Key Question 5 What are the Pollutant Sources
and Pathways?
Legend 1 CERCLIS - Superfund 6
NPDES 11 Industrial Facilities
Discharge 40 Mineral Industry
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Pollutant Pathways

• Use of GIS in Pollutant Transport Modeling

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How GIS Fits Into BASINS the TMDL Process
Landuse and pollutant specific Data
Landscape data
Meteorological Data
Point Sources
Windows interface
GIS
Landuse Distribution
Core Model
Stream Data
Post Processing
CH2MHILL
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Atascosa DEM Terrain Processing
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Atascosa Subwatershed Creation
Used a Threshold of 60 to create
33 Catchments

• 2 Gaging Stations and
• Outlet
• _____________________
• 36 Subwatersheds

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Whats Next

• BASINS Predefined Delineation Process
• Shapefiles and Tables
• Subbasins
• Streams
• Outlet

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