1. Freshwater Inflows: Relationships between Water Quality Variables in San Antonio Bay Laura Chu UT Marine Science GISWR Fall 2004

2. Background Significance Significance Inflows into Inflows into Texas estuaries Modeling Modeling San Antonio Bay San Antonio Bay Data sources Data sources TNRCC TNRCC NCDC & USGS NCDC & USGS Surfa ce Area: 531 km2 Drai nage Area: 53, 100 km2 Aver age Dept h: 2. 0 m Aver age Salini ty: 1 3 ppt Av. Daily FW Inflo w: 1 16 m3/s

3. Objectives Spatial relationships between nutrients, dissolved O 2, and fecal coliform bacteria as they pertain to inflows and salinity Spatial relationships between nutrients, dissolved O 2, and fecal coliform bacteria as they pertain to inflows and salinity Temporal relationships between the above factors Temporal relationships between the above factors Effect of wind on dissolved oxygen concentration Effect of wind on dissolved oxygen concentration If significant correlations are found, input factors into a weighted model using model builder If significant correlations are found, input factors into a weighted model using model builder

4. Project Plan Correlation graphs Correlations Tracking AnalystModel Builder Input Data Dissolved O2 Water temperature Salinity Wind Freshwater inflows NH3, DOC, PO4 Fecal coliform

5. Steps to Process Data Challenges: 2002 data doesn’t load right LOTS of file types Tracking analyst animations don’t display properly Couldn’t find nice correlations, therefore haven’t used model builder Found that data points aren’t taken at equal intervals

6. Correlations over time By variable: Salinity By variable: Salinity By Station: 13397 By Station: 13397

7. Changing Salinity & Fecal coliform

8. Effect of Wind Does wind intensity and direction affect DO? Does wind intensity and direction affect DO?

9. Freshwater Inputs Unknown event size Unknown event size

10. Spatial Representation : Tracking Analyst Animations! Animations! Freshwater inflows, fecal coliform and dissolved O 2 Freshwater inflows, fecal coliform and dissolved O 2 Challenges Challenges Loading data Loading data Averages over time Averages over time Data sampling Data samplingfrequency

11. Conclusions NO seasonal correlations NO seasonal correlations Weak spatial patterns Weak spatial patterns Dissolved oxygen affected by wind Dissolved oxygen affected by wind

12. Future Work & Modifications Model builder to incorporate factors Model builder to incorporate factors Mathematical relationships Mathematical relationships Find missing factors Find missing factors Weighted model of how freshwater inputs affect biological indicator species Weighted model of how freshwater inputs affect biological indicator species

13. Questions?