Tag Archive for: Lake Houston Dam Spillway Improvement Project

Public Comment Period on Gates Closes Monday

The Army Corps’ public comment period for adding additional gates to Lake Houston will close on Monday, 8/23/2021. The Army Corps first posted the public notice on 7/22/21.

Public comment periods are not only for those who object to plans. The public may also support plans. And I plan to support the plan.

Cross section of proposed improvements to dam.

The Corps’ website contains the full public notice, which features a summary of the project, the project plans, and an analysis of the alternatives. These are much more thorough and detailed than any documents published to date. For the historical record, I have copied them to Reports Page of this website under the “Lake Houston Dam Spillway Improvement Project” tab. See:

Project Description

The City of Houston proposes to improve 1,000 feet of the uncontrolled Ambursen spillway with the installation of new, controlled, Obermeyer spillway gates along the western portion of the existing Lake Houston Dam structure.

To accomplish this, the existing spillway crest would be lowered approximately 3.5 ft and fitted with an Obermeyer spillway gate structure. To further stabilize the dam structure, 150,000 cubic yards of rubble backfill will be deposited within the same 1,000 ft of the existing concrete structure.

The temporary cofferdam would be installed in sections that would enable the construction of a single Obermeyer spillway gate at a time. To facilitate access from the downstream side, backfill would then be installed within the Ambursen bays and in the downstream concrete-lined channel.

The spillway crest of the existing Ambursen spillway would then be demolished and the new concrete crest with the associated Obermeyer spillway gates and hydromechanical works would be built. The timeframe to complete this project will be approximately 18 to 24 months.

Avoidance and Minimization of Negative Impacts

The City conducted a thorough and extensive planning process to design a project that avoids and minimizes impacts to wetlands, special aquatic sites, and Waters of the United States as much as possible and feasible, while also satisfying the need.

During Hurricane Harvey, rainwater entered the lake at a rate of 430,000 cubic feet per second. An estimated 20,000 homes and businesses were flooded upstream. The reservoir passed the equivalent of its own storage capacity every half hour.

Due to the large influx of water over a short amount of time, the Lake Houston Dam was not able to release water fast enough to protect area homes, businesses, and public infrastructure from floodwater. Improvements are needed to the Lake Houston Dam to enable controlled releases ahead of major storm events and to further stabilize the 70-year-old structure.

This 36-page analysis shows the alternatives considered by project engineers. It also contains a matrix comparing the pros and cons of 11 alternatives, and which among them was the Least Environmentally Damaging Practicable Alternative.

By improving the existing dam, floodwaters can be rapidly released under controlled circumstances or stored to meet drinking water needs.

Please Support

Lake Houston Area leaders identified the need for a larger release capacity early on as one of three primary objectives (upstream detention to slow down inbound water, dredging to speed up throughput, and more gates to speed up outflow).

Approximately 20,000 homes and businesses flooded when water could not get out of the lake fast enough. We need this project.

  • Benefits of the project include:
  • Reduction of flood heights
  • Protection of property
  • Faster release rate reduces uncertainty associated with pre-releases when attempting to add extra capacity to the lake in advance of approaching storms.
  • Saves water needed for drinking

How to Submit Comments 

To support this project, email comments to the Regulatory Division, U.S. Army Corps of Engineers, Galveston District by clicking this link:  Public Notice Comment Email. Make sure you reference the public notice number: SWG-2020-00271, and be sure to include your name address, and phone number.

Posted by Bob Rehak on 8/21/21

1453 Days since Hurricane Harvey