Tag Archive for: Lake Houston Dam Spillway Improvement Project

Flickinger Issues Updates on Multiple Lake Houston Dam Issues

3/8/25 – Houston District E City Council Member Fred Flickinger’s March newsletter contained updates on several Lake Houston Dam projects.

Floodgate Update

Adding more and bigger floodgates to the Lake Houston Dam will let the City lower lake levels faster in advance of major storms to reduce flood risk.

According to Flickinger, Phase II of the Lake Houston Dam Spillway Improvement Project is well underway. This phase focuses adding eleven new tainter gates. Together, they will increase discharge capacity by 79,000 cubic feet per second (cfs). And that matches the peak release rate of Lake Conroe during Harvey.

Looking west across Lake Houston Dam. The current plan to add more floodgates focuses on the earthen embankment in the foreground.

Engineering firm Black & Veatch has completed the 30% design plans. Also field activities, such as ground surveys, bathymetric surveys and geotechnical soil borings are underway. Environmental investigations including wetlands assessments, endangered species studies, and archaeological site evaluations begin next week.

In parallel, engineers are working with regulatory agencies. They include the Texas Commission on Environmental Quality (TCEQ), United States Army Corps of Engineers, and Texas Parks and Wildlife Department (TPWD). Together, they hope to streamline permitting.

The Coastal Water Authority (CWA) also met with TCEQ in December. CWA continues to work closely with the Corps and TPWD to speed approvals.

Future Lake Houston Dam Replacement Study

Recognizing the long-term needs of the region, planning is also underway for a larger project to replace the existing 75-year-old Lake Houston Dam. CWA has engaged Black & Veatch to initiate a high-level Lake Houston Dam Replacement Study in 2025.

Lake Houston Dam Repair Project – Immediate

In addition to expansion and long-term replacement planning, immediate repairs are being implemented through the $10 million Pre-Disaster Mitigation Grant Project, made possible with the support of Congressman Dan Crenshaw. This project includes:

  • Grouting voids below and around the dam structure
  • Repairing spalled concrete on spillway buttress walls

“Spalled concrete” refers to a condition where concrete begins to crack, chip, or flake away from its surface. This can expose the aggregate or reinforcing steel underneath.

Essentially, it’s a form of concrete deterioration where pieces of the surface break off, leaving pitted areas. Spalling can weaken the structural integrity of concrete and lead to further damage if left unaddressed. 

CWA is finalizing the scope and fee for additional field investigations and engineering design work. These efforts will define the exact repair locations and methodologies for construction. The engineering should take six to eight months. And construction should last another six to nine months after that.

Lake Levels Lowered for Fieldwork

Houston Public Works has lowered Lake Houston to approximately 41.0 feet. Lake Houston has a normal pool elevation of 42.4 feet.

The lower level will keep water from going over the spillway, so that another CWA engineering firm, Freese & Nichols, can perform surveys of the concrete hearth structure on the downstream side of the spillway.

Lake Level has been lowered so engineers can survey the concrete on the downstream side of the 3,100 foot spillway in the foreground.

After completion of the surveys during the week of March 14th, the levels in Lake Houston will naturally return to 42.4 feet, through rain events.

Flickinger says the District E office remains actively involved in this project. His team participates in bi-weekly coordination meetings to ensure progress continues efficiently and transparently.

Property owners along the lake should secure all belongings located at the shoreline, boat docks, and piers. Be prepared for changing lake levels, as advance notice may not be possible.

Posted by Bob Rehak on 3/8/25

2748 Days since Hurricane Harvey

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