Tag Archive for: Spring Creek Detention

April 7 Meeting on Spring Creek Flood Control Dams

Spring Creek Flood Control Dams are back in the news. The San Jacinto River Authority (SJRA) recently announced the first of three meetings related to a feasibility study. So save the date – April 7.

According to Matt Barrett of the SJRA, this feasibility study is a continuation of the Spring Creek Siting Study which came out of the San Jacinto Regional Watershed Master Drainage Plan project (SJMDP). The Harris County Flood Control District (HCFCD) and multiple partner agencies including SJRA developed the Master Drainage Plan. 

Overview of Feasibility Study 

The Spring Creek Siting Study from December 2020 explored multiple alternative locations that could provide flood-mitigation benefits to the Spring Creek watershed. Two of the more cost-effective were dams on Walnut and Birch Creeks.   

The Spring Creek Flood Control Dams Feasibility Study will include:

  • A conceptual design for each dam
  • Benefits and costs for each dam and a combination of the two dams.  

The goal: to determine the most feasible and economical alternative(s) for possible future design and construction. 

The cost of the study is estimated at $1 million. The Texas Water Development Board (TWDB) Flood Infrastructure Fund (FIF) grant program will provide half.  City of Humble, HCFCD, and five (5) Municipal Utility Districts will fund the other half.  SJRA is performing in-kind services to reduce the local match amount to be funded by the Partners. 

One Crucial Step of Many

This project is currently only in the feasibility phase. Construction of one or both dams, if feasible, would likely not occur for several years. Partners still need to identify a project sponsor and funding. They also need to perform final design, obtain environmental permits, and acquire land.

Details of Public Input Meeting

Public input and participation are critical components of this study, and SJRA wants to hear from you.  A public meeting related to the study will be held on/at the following date and location:

Thursday, April 7, 2022 

6:00 p.m. to 8:00 p.m. 

Fields Store Community Center 

26098 FM 362 

Waller, Texas  77484 

The meeting will be in an open-house format, allowing members of the public to come and go at their convenience at any time between 6:00 p.m. and 8:00 p.m.  A five-minute, high-level, project-summary presentation will be given at 6:00 p.m., 6:30 p.m., 7:00 p.m., and 7:30 p.m.  

Between these presentations, project team members will answer questions and collect input.  If you can’t attend in person, you can view the summary presentation on SJRA’s Facebook page following the meeting. You may also submit questions via email and the project team will answer them. 

Project Location

Below, see preliminary maps.  These project areas could change based on the results of study efforts. 

The proposed Spring Creek Flood Control Dams would lie in far northeastern Waller County, a few miles west of Magnolia in Montgomery County.

The next map shows parcels of land that partners would need to acquire to develop the project(s).

Preliminary map of Birch and Walnut Creeks flood control dams. Extent of inundation limits subject to change during study.
One more public engagement meeting will be held this summer. The third will happen after partners release the draft report in February, next year.

Projected Benefits of Projects

As presently conceived, the Birch Creek dam could reduce water surface elevations by a half foot in a 100-year storm for almost 26 miles downstream. The larger Walnut Creek dam could produce a similar benefit for 41 miles downstream.

Each would cut the annual chance of exceedance (ACE) in half for the people in the affected areas. Thus, a hundred year storm would only have the impact of a 50-year storm.

Barrett currently estimates that the Birch Creek Dam could remove 815 structures from the 100-year floodplain and the Walnut Creek Dam could remove 1205. However, he also points out that those numbers will likely change as a result of updated modeling in the current study now underway.

How much would these dams benefit people in the Lake Houston Area? Barrett admits the impact would be small that far downstream. But he also points out that these represent the first two of 16 similar projects proposed in the Master Drainage Plan, and that they could have a major cumulative impact.

Every little bit helps. Even if you can’t attend the meeting, I hope you submit a public comment via email in support of the project.

How to Learn More and Provide Public Comment

For a fact sheet on each of the two proposed dams, click here.

For more information about the Spring Creek Flood Control Dams Feasibility Study, please visit www.SpringCreekStudy.com.

You can submit comments at the public meeting and throughout the duration of the study. Email comments to floodmanagementdivision@sjra.net, or submitted online at www.SpringCreekStudy.com

Posted by Bob Rehak on 3/18/2022

1662 Days since Hurricane Harvey

SJRA Applies for TWDB Grant to Study Feasibility of Flood Control Dams in Spring Creek Watershed

The San Jacinto River Authority (SJRA) has applied for a $500,000 grant from the Texas Water Development Board’s Flood Infrastructure Fund to study the possibility of building two flood control dams in the upper Spring Creek Watershed.

Spring Creek enters the West Fork and Lake Houston at US59. The watershed extends west from there and covers portions of Montgomery, Harris, Grimes, and Waller Counties. Spring Creek itself acts as the county line between Harris and Montgomery Counties.

Feasibility Study Would Build on Basin-Wide Study

The proposed project builds on a Spring Creek Siting Study, currently underway as part of the San Jacinto Regional Watershed Master Drainage Plan project. The latter should be released this fall.

The Siting Study, still in draft form, has identified two potential locations. One is along Walnut Creek and the other on Birch Creek.

Both have potential to mitigate flooding in the watershed. SJRA anticipates the Master Watershed Drainage Plan will recommend them for implementation. See draft spec sheets below.

Draft Walnut Creek spec sheet supplied as part of grant application
Draft Birch Creek spec sheet supplied as part of grant application

Notice that neither of these projects comes close to competing with the Barker or Addicks Reservoirs in terms of acre-feet of storage. At roughly 20,000 acre feet combined, they are roughly one twentieth the size of Barker and Addicks combined. That said, the proposed reservoirs could each still reduce flooding by up to half a foot for 25-40 miles downstream.

Grant Covers Everything Up Through Costing

The next phase of efforts related to the reservoirs will require, at a minimum:

  • Environmental due diligence
  • Site investigations
  • Literature and mapping review
  • Permitting requirement investigations
  • Desktop surveys/assessments
  • Preliminary coordination with permitting agency
  • Conceptual design of dams to determine feasibility – geotechnical borings, alternative configurations development, H&H modeling analysis, etc.
  • Cost estimate development – dam construction costs, as well as costs related to land acquisition, utility conflicts and relocations, environmental mitigation, O&M, etc.
  • Update benefit/cost ratios (BCR) from SJRWMDP using data developed as part of this effort.

Completion of these tasks will determine feasibility and cost-effectiveness. The grant will also help determine what should proceed to preliminary engineering, final design and construction.

Upstream Benefits of Project

Spring Creek watershed flood mitigation will benefit all areas impacted by Hurricane Harvey, as well as storms in 2016 (Tax Day and Memorial Day), 1994, Tropical Storm Imelda and other recent and historical events.

The most substantial benefits would accrue to structures within the Spring Creek Watershed. SJRA estimates the Birch and Walnut Creek reservoirs could remove 918 and 1,412 structures, from the 100-year floodplain based on Atlas-14 data.

Preliminary benefit/cost ratio (BCR) estimates range from 0.55-0.83 for Birch Creek to 0.78-1.06 for Walnut. However, SJRA feels the combined BCR of the two reservoirs could increase to 2.7 if social benefits typically allowed in FEMA grants are also included.

Downstream Benefits

Project benefits also extend farther downstream. In the event of major storms, the dams could delay water migrating downstream. That would help protect thousands of homes and businesses in the Lake Houston convergence zone. Remember the Plea for DDG (Detention, Dredging and Gates)? Adding to upstream detention was one of the three main strategies advocated by Lake Houston Area leaders after Harvey to reduce flooding.

The proposed dams will likely be earthen embankments with minimal permanent storage (i.e. “dry bottom” reservoirs) with and uncontrolled discharge structures and spillways.

Therefore, they will provide no water supply benefit. However, they could collect and trap sediment, which would otherwise flow into Spring Creek, the West Fork, and ultimately Lake Houston. That would reduce the loss of water storage in Lake Houston.

Timing and Partners

SJRA says it can complete the study within 18 months, but future design and construction will take longer.

SJRA will submit a separate application for an Upper San Jacinto River Basin Regional Sedimentation Study. If funded, it could help determine how much sediment the proposed dams could remove.

SJRA has not yet identified funding for operations and maintenance. This grant will not cover land acquisition, but will ultimately be required to implement construction.

For this specific application, SJRA received input from HCFCD, Harris County Precinct 4, Harris-Montgomery Counties MUD 386, Montgomery County, and Woodlands Water Agency.

To review the complete grant application, click here.

Next Steps

This is an abridged application. TWDB reviews abridged applications to rank the most important projects and ensure they have funding for them. If the abridged app is approved, SJRA must complete a more thorough application. TWDB will pass judgement on those before the end of the year.

Posted by Bob Rehak on 7/10/2020

1046 Days after Hurricane Harvey