Myths vs. Realities

Memorial Park Demonstration Project - The Project area is a section of Buffalo Bayou that flows adjacent to Memorial Park and the River Oaks Country Club, west of Shepherd Drive and east of West Loop 610. In total, the project will span from just south of Memorial Park’s Picnic Loop to approximately 1.1 miles downstream.

Myth: The bank erosion that is occurring on a portion of Buffalo Bayou is a normal process of natural streams.

Reality:

The forces that are driving bank erosion and sediment deposition on this part of Buffalo Bayou greatly exceed those that originally shaped the channel, prior to the urban development of west Houston. The rapid runoff of stormwater due to the presence of multiple water-shedding surfaces, combined with the prolonged releases of water from two upstream reservoirs, have caused the bayou’s formerly stable channel to widen and to cut away at the bases of vulnerable banks, leading to collapse. The high rate of erosion on this part of Buffalo Bayou (359 tons per year*) is also increasing the deposition of sediment into areas where the flow of water is slow. The goal of the Memorial Park Demonstration Project is to work in concert with the bayou’s natural forces, making necessary adjustments to the channel to allow it to dissipate the energy of the flowing water while avoiding destructive widening. This is the essence of Natural Channel Design: letting the stream reach a new state of dynamic equilibrium and natural stability in the face of urban change. Without this attention to the bayou’s overall form, its riparian vegetation will be continually stressed and left without a foothold to naturally protect the streambanks. The project will also benefit ongoing efforts to address the bayou’s high levels of bacteria, which can adhere to and grow on sediment particles. 

Myth: Bulldozers will strip Buffalo Bayou of woody vegetation.

Reality:

Unavoidably, heavy equipment must be used to reshape portions of the bayou to address the problems of erosion and deposition. Soil that is removed will be stored and then returned as part of the re-vegetation process using diverse native plants (trees, shrubs, forbs, and grasses) that are well-suited to the stabilization of riparian areas. (A riparian area or riparian zone is the interface between upland regions and a river or stream.) Over time, the vegetation will form a nearly closed canopy over Buffalo Bayou, much as it did prior to urban development of the Buffalo Bayou watershed and the construction of the Addicks and Barker reservoirs. BPA will closely monitor the re-vegetation process to ensure it meets the project’s goals and design criteria. 

Myth: The Harris County Flood Control District calls the plan a “demonstration project” because the county intends to use this disputed, heavy-handed method on the natural landscape of Buffalo Bayou in neighborhoods upstream.

Reality:

The project is intended to demonstrate to private landowners along Buffalo Bayou and other natural waterways in the region that by applying a collaborative, holistic approach to stream restoration, significant benefits to the stream, riparian habitat, and water quality can be realized. In contrast, the “patch-in-place” armoring and the spot repairs done by individual landowners along the bayou are leading to increased degradation of the bayou and a loss of crucial habitat.
The Harris County Flood Control District currently has no plans to apply this design methodology to other parts of Buffalo Bayou. Following construction of the project, its success will be thoroughly evaluated, with an eye to assessing applicability of Natural Channel Design concepts to maintenance practices in highly erosive areas along other bayous in Harris County.

Myth: Opponents to the project describe the plan as "pseudo-science".

Reality:

The channel evaluation and restoration methodology developed by hydrologist Dave Rosgen, Ph.D., is well established in the scientific literature, and it is increasingly employed by the civil engineering community (see link below for “Entering the Mainstream” in the August 2010 issue of Civil Engineering). It has been adopted by the U. S. Environmental Protection Agency and the U. S. Army Corps of Engineers as a preferred design approach.
Myth: Dr. Dave Rosgen is not participating in this project.

Reality:

Dr. Rosgen is a consultant to Stantec and KBR, the design engineers on the project, and he has reviewed all phases of design development. **

Myth: Vital habitat for hundreds of species of birds, animals and water creatures will be lost.

Reality:

Construction operations will temporarily disturb the habitat of birds, animals, and water creatures within the project reach of approximately 1.1 miles. The Harris County Flood Control District has observed on other projects that the animal communities within the affected area typically migrate to adjacent sections of the bayou. Upon completion of the project, birds, animals, and water creatures are expected to re-establish within the original location. This will be carefully monitored with the Memorial Park Demonstration Project. Concerns about habitat restoration strategy are understandable, although this is not a new concept. For example, similar concerns were raised when the idea of constructing marsh terraces and marsh mounds to restore salt marshes in Galveston Bay was first proposed. Ultimately, the benefits to the habitat far outweighed the temporary disturbance during construction.

Myth: All that is needed to correct the erosion problem is to re-vegetate the bayou’s banks with native plants.

Reality:

Vegetation can be a powerful healer in streams, particularly if they are free of major disturbances such as poor grazing practices, vehicular access to the streambed, or urban development. Buffalo Bayou, on the other hand, must now accommodate vastly increased flows of runoff – over relatively short periods of time – from its heavily developed watershed. In addition, it must adapt to the periodic prolonged releases from the Addicks and Barker reservoirs. The bayou has not yet reached a new equilibrium. If not aided, it will continue to adjust its pattern and widen, damaging habitats and property along the way. Vegetation can exert a strong stabilizing force on the bayous, but there are limits to what vegetation alone can achieve given the profound modifications to the Buffalo Bayou watershed.

Myth: The project will dig up and fill in some of the last evidence of our natural, geologic and archaeological history.

Reality:

The Harris County Flood Control District completed extensive cultural resource surveys within the project area and has coordinated with the Texas Historical Commission and the U. S. Army Corps of Engineers to determine if the proposed project will have any impact on cultural sites. Fieldwork and historic research completed along the banks of the bayou have shown there is no indication that archaeological deposits or historic standing structures associated with Camp Logan or other cultural resources will be affected by the project. The Texas Historical Commission and the U. S. Army Corps of Engineers are reviewing project plans to verify this conclusion.

Myth: Toe wood bank stabilization will be hazardous to paddlers.

Reality:

Faster currents occur on the outside of bends in rivers. By placing the submerged tree root wads in the toe of the bank, below the level of the water’s surface, this stabilization will slow velocity of the water on the outside of the bayou bends. This, in turn, will reduce erosion and guide paddlers toward the center of the channel where the relatively faster water will flow. The hazard for paddlers will be no greater than what is encountered in other natural streams, where downed trees have performed this slowing function for thousands of years. 
Toe wood using willow cuttings & transplants  - Bitterroot River, Montana Toe wood using willow cuttings & transplants - Bitterroot River, Montana
 
 Footnotes:
* Calculated by Harris County Flood Control District from the 80% plans.
** Verified by phone conversation with Stantec in October, 2014