City of Austin - Twin Oaks Library


  • Category: Community
  • Organization Location: Twin Oaks Library, Austin, Texas
  • Activity: Retrofit the rainwater collection system for improved water conservation and stormwater runoff reduction.


The 5,000-gallon rainwater harvesting system was initially installed in 2010 to educate the public about the benefits of stormwater management and to conserve potable water by providing captured rainwater and air conditioner condensate to an on-site landscape irrigation system. The City of Austin, in collaboration with Geosyntec Consultants and the Water Environment Research Foundation, decided to retrofit the system to allow integration of system controls with real-time weather forecasts. The retrofit was part of a pilot study to demonstrate the technology as an innovative and improved approach for rainwater harvesting system management.

To improve water conservation during dry periods, irrigation volume is automatically reduced when the cisterns are less than half full. In advance of forecasted storm events with a probability greater than 60 percent, the cisterns are automatically drained as needed to increase available storage capacity for the forecasted runoff volume. Water drained from the tanks prior to storm events is directed to the irrigation system and an on-site rain garden. The retrofit of the rainwater harvesting system at the Twin Oaks Library demonstrates the applicability and benefits of this innovative technology as a cost-effective measure for water conservation and stormwater runoff reduction.

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