Buffalo Bayou – Memorial Park Demonstration Project
By Alex Gonsalez
Art by Dorsey
Sitting more than 50 miles from the nearest beach, it is difficult to think of Houston as a water city. When we consider its history, however, Houston has everything to do with water.
According to Houston historian Louis Aulbach, even before European explorers found their way to the Gulf of Mexico, Native Americans camped and traded along the clear, clay-bottomed waters of Buffalo Bayou. Aeons before that, this land was built from sediment flow from the Rockies.
Houston’s location near the Gulf of Mexico has put it in the path of hurricanes and constant rain. This land was prone to flooding long before the arrival of humans, and natural-disasters in Houston are always related to water — either the lack of it or abundance. As Houstonians, we have always been in a constant fight with water — trying to extract it, contain it, drain it, or, most recently: control its flow.
After a total of 16 floods in the 100 year-stretch from 1836 to 1936, Houstonians realized something had to be done to control the flow and drainage of water in the city. In 1942 and 1946, respectively, the Barker and Addicks Dams were built with the aim to slow down the flow into the Buffalo Bayou.
The construction of the dams led to several flood-control attempts along the rest of the Bayou, the most obvious being concrete channelization, done in an attempt to protect the stream from erosion. Although erosion control was indeed successful, concrete channelization alters the ecosystem of a river and increases the velocity of its flow. After Tropical Storm Allison caused $5 billion in property damage in 2002, governmental and civic leaders recognized that concrete channelization is not the most effective flood mitigation measure.
Analyzing the need for a properly engineered project, the Buffalo Bayou Promenade project emerged as a means of both providing flood control and a green amenity for downtown Houston. Instead of slabbing pure impermeable concrete on the channel, the restoration of the Bayou was done using gabion sacks (filled with 100% recycled crushed concrete) and cages forming a 91.5% water-permeable river edge. This project improved the channel’s ability to withstand storm water velocity (shear stress) by 400%, thus reducing the damaging effects to the stream channel.
Development surrounding the bayou has been studied extensively and has been found to be related to its erosion and degradation. In the book Infrastructure Landscape, authors Gerdo Aquino and Ying-Yu Hang mention heavy urbanization of the area surrounding the Bayou, along with haphazard engineering on the watershed, increased runoff from impervious surface areas such as parking lots and freeways following the Bayou.
The severe detriment of the river basin calls for restoration of its shore. With this in mind, the Harris County Flood Control Department and the Buffalo Bayou Partnership got together with engineering consultants, environmental scientists, and recreational developers to develop the Memorial Park Demonstration Project. Initially, this project encompasses the stretch of the Bayou that flows through Memorial Park and the River Oaks Country Club, east of Loop 610 and west of Shepherd Drive. However, if successful, there are plans to implement this on other lengths of the Bayou.
The biggest goal of the project is to restore the rich biodiversity of the Bayou while continuing to provide a recreational area. To accomplish restoration, earth and sediment that has accumulated along the Bayou will be excavated and removed. The inside bend of the bayou will have shallower slopes, which will decrease the flow velocity to imitate the natural flow of a river. In an attempt to return the Bayou to its original structure, meanders will be reintroduced, which will also reduce the velocity of the water flow.
The most remarkable engineering element of this project, however, is the lack of regard for the Bayou’s riparian buffer (the trees, shrubs, and grasses that grow along the banks). The actions described above will require an incredible amount of work involving heavy machinery around the edges of the river, which will contribute to its detriment.
These trees and bushes prevent erosion, cleanse runoff before it arrives in the stream and create some of the most fertile soil on earth. Several studies in environmental sciences, geology, geomorphology, and related areas have found that vegetation and sedimentary deposits along meandering rivers are essential to their health.
Dr. Mathias Kondolf of the University of California, one of the world’s leading river scientists, has done a detailed study of the state of the riparian buffer along our Buffalo Bayou. Dr. Kondolf points to a lack of science underlying the engineering designed by Harris County Flood Control District in their attempt to “save” the Bayou.
It is not all bad news, however. The Army Corp of Engineers has not yet issued a permit for the project to start. There is still time to act. If you would like to get involved to help save the Bayou, access savebuffalobayou.org or visit the Save Buffalo Bayou Facebook page for more information.
by Guest Author