The 100-Year Floodplain refers to the area that will flood in the event of a 100-year storm, which has a 1% chance of occurring every year. The standard 100-year storm in Austin has a duration of 24 hours and produces over 10 inches of rainfall. The last one in Austin was in 2010 as a result of Tropical Storm Hermine.
This map shows the floodplain near the Creek Monster Habitat.
The bands around the trees represent the waterline in the event of one of these floods.
In smaller storms, flooding can still be an issue. Flooding occurs when water can’t drain quickly enough during a big storm. To help water drain, you can build a rain garden. Rain gardens collect rainwater from your roof, driveway, or street, and allow it to soak into the ground.
The Waller Creek Watershed
A watershed is an area of land that channels rainfall and snowmelt into creeks, streams, and rivers, and eventually to outflow points like reservoirs, lakes, and the ocean. Water flows from higher ground to rivers and streams and eventually ends up in larger bodies of water. As that water flows, it often picks up pollutants, which may have adverse effects on the ecology of the body of water in which it ends up.
Waller Creek draws from a narrow but completely urban watershed that is 6 miles long. At UT, 95% of campus stormwater is directed to Waller Creek. That water ultimately ends up in Lady Bird Lake.
This map shows the watershed in its entirety and how the land around it is used.