City of Austin Detention Ponds Desktop Field Analysis Laton Carr

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

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

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

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

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

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

Contributing Drainage Area Create base map: Gather data COA GIS

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

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

Contributing Drainage Area Create base map: Building a geodatabase

Contributing Drainage Area Create base map: Projecting Data

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

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

Contributing Drainage Area Analyze Map: Find drainage area at pond inlet. Flow accumulation = 2701 x (10 x 10) m2 x (1 km / 1000m)2 = 0.2701 km2

Volume of Pond Analyze map: Create new polygon feature class

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

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

Inundation Area Analyze map: Delineate inundation area

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

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

Thank you Questions or Comments