Construction crews have begun dam excavation work as part of the Old Lampasas Dam Modernization project in Northwest Austin, according to Capital Delivery Services officials in a Jan. 28 construction update.

How we got here

According to CDS officials, the dam was first built in 1984 and damaged in 2010 during Tropical Storm Hermine. The condition of the outlet pipe, poor construction materials, and erosion of the embankment and downstream slope have caused numerous holes to form on the upstream slope of the dam, creating unsafe slopes.

What's happening?

The $14.9 million project began in October and aims to modernize the dam to reduce the risk of flooding, prevent dam erosion, improve Bull Creek water quality and maintain Jollyville Plateau salamander habitats, as previously reported by Community Impact.


CDS officials said the modernized dam will meet city and state safety regulations and significantly reduce the risk of failure by:
  • Replacing the damaged outlet pipe
  • Improving the spillway
  • Modifying the shape and elevation of the embankment
  • Installing new flood early warning systems
  • Relocating a wastewater line
Ongoing work now includes excavating the dam area by removing rock and soil to create a new foundation.
The project is expected to begin Oct. 21 and last 18 months, according to Cantú and a Sept. 17 presentation from Austin’s CDS department. (Rendering courtesy Austin Capital Delivery Services Department)
Work includes replacing the dam's damaged outlet pipe, improving the spillway, modifying the shape and elevation of the embankment and more in order to reduce the risk of flooding, prevent dam erosion and improve Bull Creek water quality. (Rendering courtesy Austin Capital Delivery Services Department)
What residents should know

Increased construction noise can be expected in the area as work on the next phase begins, per the update.

Construction hours are 7 a.m.-7 p.m. Monday-Friday and 8 a.m.-7 p.m. on Saturdays. Officials said the project team will notify residents in advance of any weekend work.

The project is expected to be completed by spring 2026.




A quick note

Per the update, trees and boulders cleared during the first phase of construction will be used for the Cities Connection Children to Nature initiative, where local organizations repurpose materials into nature play features and outdoor classroom spaces across Austin.