Z-05 Fluvial Geomorphic Assessment to Improve Bank Stability and Resiliency of Buffalo Bayou

Z-05 Fluvial Geomorphic Assessment to Improve Bank Stability and Resiliency of Buffalo Bayou
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Recent Actions

May 19, 2020 - Harris County Commissioners Court approved new Bond ID added to the 2018 Bond Program List.

September 24, 2019 - Harris County Commissioners Court authorized a $289,002 agreement with Buffalo Bayou Partnership in support of this project.

January 29, 2019 - Harris County Commissioners Court authorized initiation of Bond ID Z-05 Advanced Emerging Technologies for Flood Damage Reduction. This Flood Control District project to provide a fluvial geomorphic assessment of Buffalo Bayou to improve stability and resiliency is one of several projects included under Z-05.

Project Description

The Buffalo Bayou Fluvial Geomorphic Assessment (BBFGA) is a project to investigate the environmental conditions responsible for bank erosion and sedimentation issues along Buffalo Bayou from Shepherd Dr. to Jensen Dr., including intense rainfall events and a variety of other external forces. Several extreme flood events have occurred since the completion of Buffalo Bayou Park in 2015, most notably, Hurricane Harvey in August 2017.

The BBFGA aims to improve the stability and resiliency of Buffalo Bayou’s banks and create a plan for bio-stabilization of key areas that were either damaged and repaired following Hurricane Harvey or are identified in this BBFGA as needing attention. The BBFGA was conducted from November 2019 to December 2020.

The primary objectives include:

  • Quantify and map spatial extents and types of channel stability issues
  • Understand the causes of erosion
  • Develop conceptual, practical and executable solutions to erosion issues with appropriate regard to stormwater conveyance, site stability and public accessibility
  • Develop a prioritized project list and high-level cost estimates to address the erosion and sedimentation issues

The prioritized project list from the BBFGA is awaiting the completion of the U.S. Army Corps of Engineers’ Buffalo Bayou Tributaries and Resilience Study (BBTRS). Draft alternatives within the U.S. Army Corps of Engineers’ study may have a direct impact on the BBFGA prioritized project list.

Multiple sites within Buffalo Bayou Park were recently repaired from storm damages caused by Hurricane Harvey and are currently in the establishment phase to initially stabilize the slopes with turfgrass following construction. Additional revegetation of the Hurricane Harvey repairs is being planned using recommendations from the BBFGA.

What does bio-stabilization mean?

The combined use of vegetation and structural elements to control erosion by stabilizing and strengthening soil. This streambank stabilization technique is often referred to as bio-stabilization.

There are areas of Buffalo Bayou Park that don’t have any grass or vegetation. What's happening in those areas?

Any time water levels rise significantly for extended periods of time, the vegetation and stability of the banks can be affected. Heavy rains or releases from Addicks and/or Barker Reservoirs can result in elevated water levels. Therefore, the many extended periods of high water make it difficult for vegetation to survive. There are also purposely designed ‘sediment benches’ in some of the low, flat areas adjacent to the channel that collect sediment transported by the water during storms and reservoir releases. These sediment benches are periodically accessed with equipment to remove the deposited sediment and are then revegetated with turf grass.

What kind of plants will be used in the revegetation effort?

Native trees and shrubs, including species like bald cypress, green ash, willow stakes, sycamore, willow oak, water oak, spicebush, and wax myrtle, will be planted to supplement the planted turf grasses. The final determination of species will be dependent on sourcing availability at the time of planting.

When will the storm damage repairs be revegetated?

The storm damage repairs are in the process of being revegetated with Bermuda grass as an effective stabilization measure. The supplemental native trees and shrubs will be planted in the fall and early winter of 2021, which is a more favorable planting time for woody species to achieve the highest rate of survivorship. Buffalo Bayou Partnership has planted a small area to serve as a prototype for the larger revegetation project that will occur later this year.

What is the study area for the BBFGA?

The assessment was performed along Buffalo Bayou from Shepherd Dr. to Jensen Dr., approximately 25,700 Linear Feet (LF), which is nearly 5 miles.

What will the BBFGA results look like?

The results will outline the findings of the BBFGA by identifying current areas of instability and potential project types to achieve improved channel stability and resiliency. These potential project types include:

  • Structural bank repairs
  • Erosion control features
  • A combination of multiple stabilization approaches

The BBFGA includes a prioritization list of potential projects based on a scoring system that considers the following factors:

  • Erosion severity
  • Erosion threat to infrastructure
  • Accessibility
  • Visibility
  • Permitting
  • Soil type

When and how will the public learn the BBFGA results?

The results will be posted to this project web page. The draft Buffalo Bayou Fluvial Geomorphic Assessment (BBFGA) is awaiting the completion of the U.S. Army Corps of Engineers’ Buffalo Bayou Tributaries and Resilience Study (BBTRS). The draft alternatives within the BBTRS study may have a direct impact on the BBFGA prioritized project list. Once we have more information from the BBTRS and have considered the potential impact on BBFGA, a public meeting will be scheduled.