Freshwater Inflows: Relationships between Water Quality Variables in San Antonio Bay

1
Freshwater Inflows Relationships between Water
Quality Variables in San Antonio Bay

• Laura Chu
• UT Marine Science
• GISWR Fall 2004

2
Background
Surface Area   531 km2 Drainage Area   53,100
km2 Average Depth   2.0 m Average Salinity   13
ppt Av. Daily FW Inflow   116 m3/s

• Significance
• Inflows into
• Texas estuaries
• Modeling
• San Antonio Bay
• Data sources
• TNRCC
• NCDC USGS

3
Objectives

• Spatial relationships between nutrients,
  dissolved O2, and fecal coliform bacteria as they
  pertain to inflows and salinity
• Temporal relationships between the above factors
• Effect of wind on dissolved oxygen concentration
• If significant correlations are found, input
  factors into a weighted model using model builder

4
Project Plan
5
Steps to Process Data

• Challenges
• 2002 data doesnt load right
• LOTS of file types
• Tracking analyst animations dont display
  properly
• Couldnt find nice correlations, therefore
  havent used model builder
• Found that data points arent taken at equal
  intervals

6
Correlations over time

• By variable Salinity
• By Station 13397

7
Changing Salinity Fecal coliform
8
Effect of Wind

• Does wind intensity and direction affect DO?

9
Freshwater Inputs

• Unknown event size

10
Spatial Representation Tracking Analyst

• Animations!
• Freshwater inflows, fecal coliform and dissolved
  O2
• Challenges
• Loading data
• Averages over time
• Data sampling
• frequency

11
Conclusions

• NO seasonal correlations
• Weak spatial patterns
• Dissolved oxygen affected by wind

12
Future Work Modifications

• Model builder to incorporate factors
• Mathematical relationships
• Find missing factors
• Weighted model of how freshwater inputs affect
  biological indicator species

13
Questions?