Rain Gardens as Flood Control in Austin, Texas

By Kiersten Dube

Shoal Creek Detention PondQ: Can rain gardens replace pond?

MO

PAC

Far West Blvd

Shoal

Creek

Lidar to DEM

High

Low ArcGIS Help page “Lidar to raster”

Stream Lines andFlow Accumulation

MOP

AC

Far West Blvd

AGREE50 ft

15 ft

Delineate Watershed

Far West Blvd

Area = 107 acres

Single Family Homes

Revised QuestionCan rain gardens provide flood

control for commercial property?

Civic

Multi-family

Office

Road

s

Assumption

Pond

=

Rain Gardens

Σtime

cfs

Pond Vol = Σ (Rain Garden Vol)

Pond Volume:Cut and Fill Tool

DEM

Artificial DEM

Cut Cut

Fill

Fill = Pond Vol = 2.06 x 106 cubic feet

Weir

Pond

Rain Garden Design

Soil Porosity = 0.2

4 in.

30 in.

10 in.

1.25 in.

EquivalentStorageDepth

Feasibility Assessment

=Pond VolEquivalent RG Depth

Rain Garden Area

=RG AreaWatershed Area 53%

=Pervious CoverPer Lot 56%

?

= 57

57107 =

Acres

Conclusions• Can rain gardens replace pond? – Tentative No

• Consider other options– Pervious paving– Roof top gardens– More complex RG designs

• Remaining questions– Maintenance– Water quality from roads