GISHydro Database for Tres Palacios Bay

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GIS-Hydro Database for Tres Palacios Bay

• Stephanie Johnson
• GIS in Water Resources
• Class Presentation
• November 21, 2006
• Dr. David Maidment Advisor
• UT - Center for Research in Water Resources
  (CRWR)

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Study Area
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Tres Palacios Bay

• Determined to not meet dissolved oxygen standards
  of 5 mg/L
• TCEQ begins a dissolved oxygen TMDL study
• Overseen by Dr. Paul Montagna, Texas AM Corpus
  Christi
• Water quality monitoring for the past 2 years
• UT-CRWR asked to help with water quality modeling

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Objective of Project

• Develop a GIS-based dataset for future water
  quality modeling
• Introductory qualitative analysis of monitoring
  data
• Use as a test for webscraper tool that calculates
  duration curves

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Dataset
Soils
Roads/Cities

• Base map used as a guide
• Developed by Sally Morehead, M.S. at UT-Austin
  Marine Science Institute for initial efforts in
  study
• Hydrography
• Tyler Jantzen at CRWR - NHDPlus data
• Jantzen is supported by TNRIS to develop TX
  NHDPlus Data for his M.S. thesis
• General data
• Texas General Land Office (GLO) Political
  boundaries, roads, etc.
• Federal agencies NRCS soil and landuse, etc.
• Local data sources
• TCEQ Water quality monitoring stations
• Dr. Paul Montagna water quality monitoring
  points in Tres Palacios Bay

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Tres Palacios Bay Watershed
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Monitoring Points

• 1 USGS flow gage on the Tres Palacios River
• 27 TCEQ TRACS river monitoring points
• 4 monitoring points in Tres Palacios Bay
• 17 TCEQ TRACS monitoring points in Tres Palacios
  Bay

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Qualitative Analysis

• Patterns in low D.O. levels
• Location
• Time of year
• Natural events (flow regime)
• Theorize potential sources of pollution
• Non-point vs. point
• Municipal vs. rural

(Yet to be completed)
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Load Duration Curve

• Basically a cumulative frequency distribution
• Derived from a flow duration curve
• Multiply flow duration curve by the desired
  pollutant concentration and a conversion factor
• Outcome allowable load/day

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Example
Low Flow
High Flow
Applying the water quality standard of 0.05 mg/L
TP
Source White Paper (1) Advantages and
Disadvantages of Using Load Duration Curves to
Estimate Existing and Allowable Loads for the
Development of Nutrient TMDLs
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Webscraper for Duration Curve Creation
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Raw Data
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Calculations
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Calculations (cont.)
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Future Work

• For GIS Project
• Qualitative analysis of monitoring data
• Create more duration curves for Tres Palacios
  River
• Future Modeling
• Use data to develop a dissolved oxygen water
  quality model
• Use runoff and land use data to determine the
  nutrient load from each catchment
• Create duration curves for non-point source
  nutrient loads

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Credits

• Thanks to
• Dr. David Maidment, Tyler Jantzen, Dr. Paul
  Montagna, Ernest To, Sally Morehead, CRWR staff

Photos from http//www.portofpalacios.com
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Questions?