GIS-Hydro Database GIS-Hydro Database for Tres Palacios Bayfor Tres Palacios Bay

Stephanie JohnsonStephanie Johnson

GIS in Water ResourcesGIS in Water ResourcesClass PresentationClass PresentationNovember 21, 2006November 21, 2006

Dr. David Maidment – AdvisorDr. David Maidment – AdvisorUT - Center for Research in Water Resources (CRWR)UT - Center for Research in Water Resources (CRWR)

Study AreaStudy Area

Tres Palacios Bay

Matagorda Bay

/0 10 205 Miles

Tres Palacios BayPalacios, Texas

Tres Palacios BayTres Palacios Bay

Determined to Determined to not meet dissolved oxygen not meet dissolved oxygen standardsstandards of 5 mg/L of 5 mg/L

TCEQ begins a TCEQ begins a dissolved oxygen TMDL dissolved oxygen TMDL study study Overseen by Dr. Paul Montagna, Texas A&M Overseen by Dr. Paul Montagna, Texas A&M

Corpus ChristiCorpus Christi Water quality monitoring for the past 2 yearsWater quality monitoring for the past 2 years

UT-CRWR asked to help with water quality UT-CRWR asked to help with water quality modelingmodeling

Objective of ProjectObjective of Project

Develop a Develop a GIS-based datasetGIS-based dataset for future water for future water quality modelingquality modeling

Introductory qualitative analysis of monitoring Introductory qualitative analysis of monitoring datadata

Use as a test for webscraper tool that Use as a test for webscraper tool that calculates calculates duration curvesduration curves

DatasetDataset

Base mapBase map – used as a guide – used as a guide Developed by Sally Morehead, M.S. at UT-Austin Marine Science Developed by Sally Morehead, M.S. at UT-Austin Marine Science

Institute for initial efforts in studyInstitute for initial efforts in study HydrographyHydrography

Tyler Jantzen at CRWR - Tyler Jantzen at CRWR - NHDPlusNHDPlus data data Jantzen is supported by TNRIS to develop TX NHDPlus Data for his Jantzen is supported by TNRIS to develop TX NHDPlus Data for his

M.S. thesisM.S. thesis General dataGeneral data

Texas General Land Office (GLO) – Political boundaries, roads, etc.Texas General Land Office (GLO) – Political boundaries, roads, etc. Federal agencies – NRCS soil and landuse, etc.Federal agencies – NRCS soil and landuse, etc.

Local data sourcesLocal data sources TCEQ – Water quality monitoring stationsTCEQ – Water quality monitoring stations Dr. Paul Montagna – water quality monitoring points in Tres Palacios Dr. Paul Montagna – water quality monitoring points in Tres Palacios

BayBay

SoilsRoads/Cities

Tres Palacios Bay Tres Palacios Bay WatershedWatershed

Matagorda Bay

Tres Palacios Bay

Monitoring PointsMonitoring Points

1 USGS flow gage1 USGS flow gage on the Tres Palacios on the Tres Palacios RiverRiver

27 TCEQ TRACS 27 TCEQ TRACS river monitoring river monitoring pointspoints

4 monitoring points4 monitoring points in Tres Palacios Bayin Tres Palacios Bay

17 TCEQ TRACS 17 TCEQ TRACS monitoring points in monitoring points in Tres Palacios BayTres Palacios Bay

Qualitative AnalysisQualitative Analysis

PatternsPatterns in low D.O. levels in low D.O. levels LocationLocation Time of yearTime of year Natural events (flow regime)Natural events (flow regime)

Theorize Theorize potential sourcespotential sources of pollution of pollution Non-point vs. pointNon-point vs. point Municipal vs. ruralMunicipal vs. rural

(Yet to be completed)

Load Duration CurveLoad Duration Curve

Basically a Basically a cumulative frequency distributioncumulative frequency distribution Derived from a flow duration curveDerived from a flow duration curve

MultiplyMultiply flow duration curve by the flow duration curve by the desired desired pollutant concentrationpollutant concentration and a conversion and a conversion factorfactor

Outcome: allowable Outcome: allowable load/dayload/day

Source: White Paper (1): Advantages and Disadvantages of Using Load Duration Curves to Estimate Existing and Allowable Loads for the Development of Nutrient TMDLs

Applying the water quality standard of 0.05 mg/L TP:

Low FlowHigh Flow

ExampleExample

Webscraper for Duration Webscraper for Duration Curve CreationCurve Creation

Raw DataRaw Data

CalculationsCalculations

Flow %

RangeFlow Regime

Number of

Samples

Avg FC Loading

(CFU/100mL)

Avg Single Sample Target

(CFU/100mL)

% Load Reductio

n

Avg Geometric

Mean Target (CFU/100mL)

% Load Reducti

on

0-10 High Flow 48 1.11E+14 1.39E+13 87.6% 6.93E+12 93.8%

10-30Moist

Conditions 113 1.45E+12 1.32E+12 8.6% 6.61E+11 54.3%

30-70 Normal Flow 179 4.70E+11 2.47E+11 47.6% 1.23E+11 73.8%

70-90Dry

Conditions 69 7.39E+10 8.59E+10 -16.2% 4.29E+10 41.9%

90-100 Low Flow 2 2.22E+09 3.84E+10 -1629.1% 1.92E+10 -764.6%

Overall Average 82 2.27E+13 3.11E+12 -300.3% 1.56E+12 -100.2%

Calculations (cont.)Calculations (cont.)

Future WorkFuture Work

For GIS ProjectFor GIS Project Qualitative analysis of monitoring dataQualitative analysis of monitoring data Create more duration curves for Tres Palacios RiverCreate more duration curves for Tres Palacios River

Future ModelingFuture Modeling Use data to Use data to developdevelop a dissolved oxygen water a dissolved oxygen water

quality quality modelmodel Use Use runoffrunoff and and land useland use data to determine the data to determine the

nutrient load from each catchmentnutrient load from each catchment Create duration curves for non-point source nutrient Create duration curves for non-point source nutrient

loadsloads

CreditsCredits

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

Photos from: http://www.portofpalacios.com

Questions?Questions?