Lake Limestone Riparian Restoration
In fall 2019, six Brazos River Authority aquatic scientists set out on a mission to address a damaged area below the Sterling C. Robertson Dam at Lake Limestone, located on the upper Navasota River in Limestone, Robertson and Leon counties.
The plan: reverse damaging practices of prior land-use methods.
Armed with two truckloads of small tree saplings, shovels, and an award-winning attitude, the crew descended on the area below the dam. They were to repair the riparian zone.
A riparian zone is the area of land between the water of a stream or river and the higher ground. Sometimes call a rivers banks, this area holds specific benefits for both the quality of the river’s water and the habitat for the fish and other water-based creatures living there.
The crew split up into two groups of three and went to opposite sides of the stream, where they would begin planting the small tree saplings. Starting upstream near the dam and moving downstream along the banks and up into the floodplain, the crews began slicing into the earth and planting each individual tree for its hopeful journey into adulthood.
After 10 hours, about 500 newly planted saplings lined the banks.
Although many different trees thrive in the riparian zone next to a stream, the types of trees selected were made with the help of the staff at the U.S. Department of Agriculture’s Natural Resource Conservation Service and the Texas A&M Forest Service. Planting trees wasn’t enough. The trees needed to be suitable for the region. The first round of trees planted included: Texas Walnut, Pecan, Mexican Buckeye, Green Ash, and Bur Oak.
Riparian trees, shrubs, and other vegetation protect the stream from pollutants and runoff, which can greatly improve water quality. They also absorb excess nutrients, including nitrogen and phosphorus, from farm and livestock operations. Trees also play a pivotal role in streambank stabilization. Trees and other vegetation along the riparian zone help to provide a barrier against moving water, which causes erosion over time and can weaken and eventually wash away large sections of a riverbank.
Riparian restoration is never a one-time event.
Some of the trees lovingly planted by BRA aquatic scientists will most likely be eaten by wildlife. Others may succumb to damages resulting from water releases at the dam. BRA aquatic scientists understand this is a marathon of love, not a sprint. They plan to revisit the site each fall for the next several years to plant more saplings in the hopes that this little stretch of the Navasota’s native riparian community can be restored.
Given that diversity is the key to any healthy ecosystem, the trees selected for future plantings may be different from those planted in the first year.
Additionally, to document the success and hopeful restoration of the riparian zones, aquatic scientists will visit the site periodically throughout the year to assess the growth of the saplings. They will also begin a Black willow stem cutting project in which suitable stems from an existing Black willow stand will be cut and replanted in the riparian zone.
The BRA’s goal is to achieve low-cost erosion control in an environmentally friendly manner.
Only time will tell the success of the aquatic scientists’ efforts, but projects like this can have a lasting positive effect on rivers and streams throughout the Brazos River basin.
In addition to helping protect and improve the water quality, trees within the riparian zone also provide critical habitat for upland wildlife and aquatic species. Trees can provide shade and a temperature refuge for fish species in summer months where stream temperatures increase, and oxygen levels decrease. Also, tree roots and debris provide excellent instream habitat for many different fish species, amphibians, and macroinvertebrates who call the river or stream environment their home.
Learn about other special projects by BRA aquatic scientists here.
Learn more about how a healthy riparian zone can also benefit communities here.