Little Walnut Creek

Austin, Texas

Little Walnut Creek, from Metric Blvd to Rutland Dr in North Austin, represents a 1,250 acre, highly urbanized watershed posing a significant flood hazard to adjacent residential homes, apartments, and roadway crossings. To help alleviate the flooding to these structures, the City of Austin Little Walnut Creek Flood Hazard Reduction project proposed a flow diversion solution to significantly reduce the amount of creek flow during the 10, 25, and 100 year storm events.

Encotech was retained by Brown and Gay Engineers to provide civil engineering services.  The project included the installation of a new 12’ x 12’ concrete box culvert that reroutes major storm water flows to a new detention facility downstream.  The box culvert is being installed through an existing subdivision and requires the replacement of sanitary sewer collection lines as well as a portion of a potable water main.  Additionally, there are numerous water and sanitary service lines that conflict with the new box culvert’s location.  Design will include a creek bypass system under Mearns Meadow Blvd and an upgrade to the culverts at Quail Valley.