SJRA Proposes Temporary, Seasonal Lake Lowering Strategy for Lake Conroe

By: Jace Houston, SJRA General Manager

Calendar year 2010 was the driest year in Texas history. Calendar year 2015 was the wettest year in Texas history. Hurricane Harvey was the largest single rainfall event in Texas history resulting in record breaking flooding across the upper Gulf Coast of Texas from the Brazos River to the Sabine River. In the aftermath of these incredibly diverse and extreme weather events, water policy makers across the entire state are struggling with the difficult challenge of storing enough water to survive a drought while figuring out ways to safely manage excess water during storms.

Even though Lake Conroe was created as a water supply reservoir, the San Jacinto River Authority (SJRA) and the City of Houston (the two entities that hold the permits for the water stored in Lake Conroe) were asked by local and statewide elected officials to consider how it might be temporarily utilized to help mitigate downstream flooding until more permanent mitigation strategies, such as dredging of the lower West Fork of the river, could be completed. In April, SJRA staff met with City of Houston staff to begin discussing ideas that could be presented to each agency’s governing body for their consideration.

The purpose of this article is to describe the temporary, seasonal lowering strategy that has been proposed for Lake Conroe so that people can understand exactly what it means and how it would work. At the time I am writing this article (on May 18, 2018), the seasonal lowering strategy is still a proposal. SJRA does not have the authority to implement the proposal on its own. At a minimum, the proposal must also be approved by the City of Houston. In addition, the Texas Commission on Environmental Quality (TCEQ) must decide whether releases from the reservoir for seasonal lowering will be debited against annual water supplies. This has a major impact on whether the proposal is viable.

The following Q&A’s summarize the action taken by SJRA’s board of directors at its meeting on April 26, 2018:

  1. What action did the SJRA board take at its April meeting? Is this the only approval needed?
    1. The SJRA board voted to PROPOSE a temporary, seasonal lake lowering strategy for Lake Conroe as a means of mitigating downstream flooding while dredging is completed in the lower West Fork of the San Jacinto River. The board’s action authorized the General Manager to deliver the proposal to the City of Houston for the City’s further consideration.
    2. The SJRA board’s action is not the final step. As the majority water-right holder in Lake Conroe, the City of Houston still has to approve the proposal.
    3. SJRA and the City of Houston are still in discussions with the TCEQ to determine how releases will be treated for purposes of water rights accounting.
  2. What exactly is the temporary, seasonal lake lowering proposal?
    1. As a point of reference, the normal pool level of Lake Conroe is 201’ msl.
    2. Spring season – April 1 through May 31.
      1. Starting on April 1, gradually reduce to and maintain the level of Lake Conroe at 200’ msl (one foot below normal pool).
      2. Starting on June 1, begin to capture flows to restore normal lake elevation.
    3. Fall season – August 1 through September 30.
      1. Starting on August 1, gradually reduce the level of Lake Conroe with a goal of reaching 200’ msl (one foot below normal pool) by August 15.
      2. After August 15, continue gradually lowering the level of Lake Conroe with a goal of reaching (and maintaining) 199’ msl (two feet below normal pool) by August 31.
      3. Starting October 1, begin to capture flows to restore normal lake elevation.
    4. If the lake level has already dropped to the target elevation just due to evaporation, no releases would be made.
    5. If a storm enters the forecast while seasonal releases are being made to lower the lake level, such releases would be stopped and the river allowed to drain out until rainfall is out of the forecast.
  3. When would the lake lowering strategy end?
    1. The intent of the proposal is to provide a near-term, flood mitigation benefit for the next one to three years while longer-term strategies, such as dredging of the lower West Fork, are completed.
    2. The SJRA board’s proposal stated that the lake lowering strategy would be reviewed annually at the February board meeting and must be renewed by a vote of the Board in order to extend it for another year.
  4. Why does SJRA’s proposed strategy for Lake Conroe not involve the pre-release of water before a storm event?
    1. Release of water from Lake Conroe prior to a storm would put flows into the San Jacinto River and Lake Houston potentially exacerbating flooding.
    2. Staff from the City of Houston, the Coastal Water Authority, and the Harris County Flood Control District have expressed their desire to not pre-fill the river and Lake Houston prior to a storm with water released from Lake Conroe.
    3. Lake Conroe is located in the upper basin where it makes sense to retain flood waters to the extent possible.

For more information please visit our website at www.sjra.net or call 936-588-3111. You can also like us on Facebook: www.facebook.com/SanJacintoRiverAuthority; follow us on Twitter: twitter.com/SJRA_1937; watch us on YouTube: www.youtube.com/user/sanjacintoriver; and view us on Flickr: www.flickr.com/photos/sanjacintoriverauthority.

Disclaimer: Here at Dock Line Magazine (DLM) we take great pride in making an effort to educate our readers on important issues. That is why we have agreed to publish three letters written to DLM on the state of our current water issues in Montgomery County. DLM has no opinion of these letters but believe we need to get the information to the public so that you as our reader can form your own educated opinion. At the time of print this was the most up to date information but we encourage you to visit our web site and social media pages for the most up to date information on this matter.