Release water year round

“Seasonal” Lake Lowering Out. “Active Storm Management” In.

The San Jacinto River Authority and City of Houston have abandoned their automatic “seasonal” lake lowering policy. The seasonal program lowered Lake Conroe automatically to fixed levels during the rainiest parts of the year (April/May and August/September, i.e., the peak of hurricane season).

They have replaced seasonal lowering with a new program called “active storm management” that gives the City and Lake Conroe dam operators more flexibility to respond to actual weather conditions.

Basically, they can keep water levels up when no storms are expected. But they can lower the lake in advance of major rain…any time of the year…by amounts that will keep the lake level as stable as possible and downstream residents as safe as possible.

It’s a compromise that can be summed up in the words “as needed vs. automatic.”

Below, you can see the exact wording of the new protocols. Below that, you can see my simplified summary/interpretation. I also provide a link to the actual contract between the City and SJRA.


Active Storm Management Protocols for Lake Conroe and Lake Houston – 2024

Spring
  • Beginning April 1 through June 1, the City of Houston may request diversions to lower Lake Conroe from normal pool of 201’ msl to create up to six inches of storage capacity for forecasted storm event inflows (to 200.5’ msl). The decision of when, how, and whether to initiate diversions will be guided by climate conditions, weather patterns, and available water supply.
  • Resume normal recapturing after each storm event that triggered any diversion between April 1 and June 1.
  • In the event a major rainfall is forecasted to impact our region, active storm management protocols of the City of Houston could initiate a diversion to create up to an additional six inches of storage capacity for storm inflows (to 200.0’ msl). It is acknowledged that under extraordinary weather circumstances, additional diversions to create capacity below 200.0’ msl could occur.
Fall
  • Beginning August 1 through October 1, the City of Houston may request diversions to lower Lake Conroe if actual lake levels are at normal pool of 201 msl to create up to six inches of storage capacity for storm inflows (to 200.5’ msl). After Labor Day, storage capacity may be increased an additional six inches (to 200.0’ msl). Diversion volumes requested to reach intended levels will be dependent on the actual lake levels. The decision of when, how, and whether to initiate diversions will be guided by climate conditions, weather patterns, and available water supply.
  • Resume normal recapturing after each storm event that triggered any diversion between August 1 and October 1.
  • If a named storm is predicted to impact our region, active storm management protocols of the City of Houston could initiate a diversion to create up to an additional six inches of storage capacity for storm inflows (to 199.5’ msl). It is acknowledged that under extraordinary weather circumstances, additional diversions to create capacity below 199.5’ msl could occur.
Protocol – Lake Houston
  • Year Round
    • City of Houston will initiate releases to lower Lake Houston prior to major rainfall events.
    • Conservation Pool Elevation is 42.4’ msl.
    • Lake Houston level reduced to 41.4’ msl if a 24-hour rainfall forecast of 3 inches or more is expected. within the Lake Houston watershed.
    • Under extraordinary weather circumstances, Lake Houston level may be reduced below 41.4’.
Duration
  • The Protocols above will extend to the end of 2024 but will be reviewed by the stakeholders in October/November of 2024. During the review, the stakeholders will discuss strategies that extend beyond 2024.
Advocacy and Education
  • All stakeholders will work to support flood mitigation projects and efforts across the upper watershed, including improvement of land use regulations to reduce runoff from new development in counties that contribute flow to Lake Houston.
  • Because public education regarding completed and ongoing downstream mitigation efforts is critical to generating upstream support for continued active storm management at Lake Conroe, all stakeholders agree to educate their constituents regarding: active storm management protocols being implemented at Lake Houston, completed and ongoing sediment removal projects in the San Jacinto River basin and Lake Houston, and continued progress on the Lake Houston spillway modifications.
  • Because of its impact on effective active storm management, all stakeholders will support City of Houston and SJRA efforts to amend the Certificate of Adjudication for Lake Conroe to increase the maximum diversion rate.
  • All stakeholders agree to support efforts to limit further construction of habitable structures around Lake Conroe below elevation 207’ msl.
Important Notes
  • All water released from Lake Conroe as part of active storm management is being accounted for from the City of Houston’s 2/3 share and reported to TCEQ by the City of Houston. Therefore, all final decisions on diversions are ultimately the City’s and must be communicated to the SJRA in writing. This includes defining active storm management protocols.
  • All flood mitigation protocols could be limited due to drought conditions.

Rehak’s Summary

Note the words “MAY REQUEST” in the first sentences under Spring and Fall. Lowering is now on an “as needed” basis, not automatic.

Note also the words “RESUME NORMAL RECAPTURING” in the second bullet points under Spring and Fall. Operators will attempt to return the lake to its normal level after the storm threat has passed. The lake will not automatically be kept lower for the rest of the season.

All stakeholders have agreed to review the policy at the end of this year and modify it as necessary.

All stakeholders have also agreed to support mitigation projects including:

  • Land use regulations that reduce runoff
  • Education of residents re:
    • Active storm management protocols at Lake Houston
    • Construction progress of more Lake Houston gates
    • Sediment removal projects
  • An increase in the maximum pre-release rate for Lake Conroe
  • Limiting future construction around Lake Conroe to a safe level (207 feet above sea level).

The City of Houston must initiate lake lowering IN WRITING.

Water released from Lake Conroe at the City’s request will be reported to the TCEQ.

The City makes all decisions on releases.

Its decisions are final.

The City may redefine “active storm management” protocols, but should consider drought conditions when making decisions.

Decisions to Lower Lake Outside of Spring/Fall Dates

A release during Tropical Storm Alberto in June this year triggered a protest from the Lake Conroe Association because it fell outside the dates indicated above (April/May and August/September).

However, during the April SJRA Board meeting at which Active Storm Management was approved unanimously, the official minutes note that all parties agreed that the City could order the release of water from Lake Conroe at any time – regardless of the season.

For the historical record, here is the actual contract between the City and SJRA re: the operation of Lake Conroe.

For ease of future reference, you can also find the details above on this site’s Lake Lowering page.

Posted by Bob Rehak on 6/25/24

2492 Days since Hurricane Harvey