Dickinson Bayou Marsh Restoration Yields Immediate Benefit

John Blaha
Dickinson Bayou Marsh Restoration Yields Immediate Benefit
CCA Texas staff member Amie Fritchman and TPWD’s Jan Culbertson planting grass seedlings. Photo by Lisa Laskowski.

Coastal wetland loss from both natural and human-induced causes is significant in Texas. Since the early-1930s, up to 50% or more of wetlands once present have been lost in many areas along our coast. Coastal wetlands loss is a continuing concern because of the essential role wetlands play in fisheries production, flood control, erosion prevention, enhanced water quality, groundwater replenishment, and recreation.

Coastal wetlands also serve as vital nursery grounds for greater than 95% of the recreationally and commercially important fisheries in the Gulf of Mexico. Texas Parks and Wildlife, Galveston Bay Foundation, Galveston Bay Estuaries Program, United States Fish and Wildlife and other entities have all taken part in many marsh restoration projects in the Galveston Bay system. Coastal Conservation Association (CCA) Texas has been a supporting member in many of these efforts including Bird Island Cove, Snake Island Cove, Oyster Lake (West Galveston Bay), and Sportsman's Road projects. The Galveston Bay National Estuary Program's (GBNEP) Comprehensive Conservation and Management Plan (CCMP) has given a very high priority to increasing the quality and quantity of wetlands, and setting as a goal the expansion of the area of vegetated wetlands in the GBNEP area by 15,000 acres within 20 years

The Dickinson Bayou Marsh Restoration project, led by Texas Parks and Wildlife Department (TPWD), was recently completed and the efforts of the project leaders are showing immediate success. The area, designated as impaired by the Environmental Protection Agency (EPA), has been affected over many years due to development, oil and gas activities, dredging activities and natural events.

The project area within the lower reaches of the Dickinson Bayou watershed has lost a considerable amount of its historic marsh acreage, due mainly to shoreline erosion. The wetland losses along with local subsidence has created a general widening of the bayou that has negatively impacted water quality in the form of low dissolved oxygen levels. Insufficient dissolved oxygen has been tagged as the root cause of at least twenty-nine fish-kill incidents within the bayou prior to the completion of the project.

The Dickinson Bayou Marsh Restoration project is somewhat unique in that it is located in the watershed of Dickinson Bayou, which flows into Galveston Bay. The project's location is a little less than 1.5 miles upstream of the HWY 146 Bridge. Marsh restoration projects typically take place along open bay shorelines and are restored and created with shoreline breaks and marsh mounding methods. The Dickinson Bayou project created 10 acres of living shoreline (new marsh) that will protect 17.7 acres of existing marsh. This project was executed using beneficial use materials to create the habitat. The beneficial use material was the material dredged from the bayou itself in order to restore historical depths within the bayou channel.

The depth of the bayou in the bend adjacent to the Humble Oilfield had decreased to approximately 4 feet due to sedimentation with depths above and below the bend averaging 12 feet. This shallow area allowed a salt wedge to form at this point as tidal exchanges occurred. This ultimately resulted in the low dissolved oxygen level events that led to the numerous fish kills.

Two living shoreline areas make up the 10 acres of restored marsh. Outer, stabilized levees were constructed with rock armor and then back filled with the beneficial use materials. TPWD and volunteers have already accomplished some grass plantings along the outer edges of the areas and within the levees as well. Once the materials in the marsh cells stabilize, a larger scale planting project will be undertaken during spring of 2017. Once stabilization and planting has occurred, the levees will be opened in some areas to allow water to flow through the marsh and provide access and egress for marine species in the area.

"Because of the two fresh water streams that flowed into this marsh area, it remained healthy during the recent drought. When we visited this area and areas above and below this site, this area had the only viable seed head for the establishing marsh grasses," commented Jan Culbertson, Texas Parks and Wildlife Coastal Ecologist and project manager. Culbertson commented further, "Because the freshwater streams into the marsh kept it healthy, this provided a perfect place for the restoration project and we are pleased at the immediate success we have seen. The project has taken some time to complete and this success makes it worth the wait."

Wetlands and marsh losses have continually increased over time along the entire Texas and Gulf coasts. These losses due to human-induced and natural events threaten the health of the coastal resources, and projects like this are important to help restore and create these critically important habitats. CCA Texas and its habitat initiative, Habitat Today for Fish Tomorrow, are committed to supporting and helping TPWD and other groups in the efforts to ensure healthy and productive coastal resources for years to come.

"CCA Texas contributed $75,000 to this project. These funds were used as matching public funds for Texas General Land Office Coastal Management Program grants," commented Jay Gardner, Habitat Today for Fish Tomorrow Committee Chairman. Gardner continued, "Public funds are important in these grants and through the efforts of CCA Texas volunteers we are able to support important projects such as this one to ensure healthy coastal resources for the future."

Be sure to visit www.ccatexas.org/project-videos/ or search "CCA Texas" on YouTube to see videos on the Dickinson Bayou project and many others.