1. City of Austin Detention Ponds
Desktop Field Analysis
Laton Carr

2. Detention Pond Classification
Watershed Protection and Development Review (WPDR)
Texas Commission of Environmental Quality (TCEQ)
Project to classify detention ponds

3. Building a Database Existing point feature class data base
Electronic versions of maps
Berm heights via memory
(maintenance crew)
Retrieval of any other existing maps
Result: Nearly empty data base

4. Course of Action
So what do you do?
Send out the intern!

5. Mission Berm or Dam? Berm/Dam dimensions Take image inside the pond
Take image downstream
Description of what lies 100 yds downstream

6. Engineer’s Request Use of GIS to:
Find contributing drainage area into a pond
Estimate volume of pond
Estimate berm/dam height
Delineate inundation area
Determine what lies within this area

7. Contributing Drainage Area
Project Parts
Contributing Drainage Area
Pond Volume
Inundation Area

8. Contributing Drainage Area
Create base map:
Gather data COA GIS

9. Contributing Drainage Area
Create base map:
Gather data (DEM)

10. Contributing Drainage Area
Create base map:
Building a geodatabase
Geodatabase
Feature Classes
Note: no feature data set.

11. Contributing Drainage Area
Create base map:
Building a geodatabase

12. Contributing Drainage Area
Create base map:
Projecting Data

13. Contributing Drainage Area
Create base map:
Terrain Processing
fdr
Fac (boxed region detail)
Dem_aus
AgreeDem
fac
Dem_aus overlain by Creeks
fil

14. Contributing Drainage Area
Create base map:
Adding Vector Data
Add Streets
Zoom to pond
Add Contours

15. Contributing Drainage Area
Analyze Map:
Find drainage area at pond inlet.
Flow accumulation
= 2701 x (10 x 10) m2 x (1 km / 1000m)2
= km2

16. Volume of Pond
Analyze map:
Create new polygon feature class

17. Volume of Pond
Analyze map:
Export Table to .dbf file

18. Volume of Pond
Analyze map:
Open in Excel and Run Macro

19. Inundation Area
Analyze map:
Delineate inundation area

20. Results Use of GIS to: Find contributing drainage area into a pond
Estimate volume of pond
Estimate berm/dam height
Delineate inundation area
Determine what lies within this area

21. Additional Work
Use a new tool TIN Volume tool for calculating pond volume
Finish procedure for estimating inundation area
Automate more of the analysis
Visual Basic
Model Builder
UML

22. Thank you Questions or Comments