A&M Systemwide: Research to help restore Caddo Lake

About Caddo Lake

Caddo Lake is the largest natural freshwater lake in the South, covering about 26,800 acres and growing to about 35,000 acres at times of high water levels.
How the lake was formed is a matter of debate. Some believe that the New Madrid earthquakes of 1811-1812 formed the lake, and others believe that the lake was formed by the Great Raft, a large mass of fallen trees in the Red River, in 1806.
The Caddo Indians, a friendly and peaceful tribe, were the area’s first settlers. In 1835 the U.S. government purchased the land for $80,000 and within a year moved the Indians away from the region.
In the mid-1800s, a region of Caddo Lake known as Old Monterey—home to a racetrack, rooster fights, saloons and brothels—was a haven for outlaws, who boasted that it averaged at least one violent death per day. Jean Lafitte, the well known pirate, had close connections in Monterey and may have visited there on several occasions.
Paddleboat and steamboat traffic through Caddo Lake was in full swing by the 1830s and transported people as well as commercial items such as iron ore, cotton, leather goods. During the Civil War, steamers were used to move military and civilian supplies to the rest of the confederacy.
In the late 1800s, after the lowering of the water level made navigation impossible, a new economic boom centered on harvesting pearls. This ended when the first dam was built.
After oil was discovered on and around Caddo Lake in the early 1900s, the lake became the site of the first over-the-water drilling platform in the United States.

Caddo Lake, the largest natural freshwater lake in the South, is on the Texas-Louisiana border.

Research to help restore Caddo Lake

by Kathryn Wythe
Texas Water Resources Institute

(College Station)—As the only natural lake in Texas, Caddo Lake, on the Louisiana border, is unique. With its bald cypress and tupelo trees, the lake is also only one of 19 wetlands designated as “of unique importance” in the United States.

Texas Agricultural Experiment Station scientists, along with the Caddo Lake Institute (a private operating foundation underwritten by musician Don Henley), The Nature Conservancy, the U.S. Army Corps of Engineers, Northeast Texas Municipal Water District and other federal and state agencies, and local citizens are working together to help Caddo Lake remain a diverse and economically important wetland.

Although other issues affect the lake, the integrity of the lake and its ecosystem are being threatened because of a lack of freshwater flow.

After the U.S. Army Corps of Engineers built Lake O’ the Pines on Big Cypress Creek upstream of Caddo in 1959, the Caddo Lake area no longer flooded as much. The regulated water flows from the dam stabilized lake levels, reducing the regeneration of bald cypress forests.

Benefits of flooding

Flooding helped sweep sediment from the lake and inhibit excessive plant growth. Invasive aquatic plants are now choking off water bodies, and heavy metals, including mercury found in the lignite coal used to power an electricity-generating plant, are accumulating in fish tissues.

At different times in its long and colorful history, Caddo Lake has been home to the Caddo Indians, a band of outlaws, and the first over-the-water drilling platform in the United States. (Photo courtesy of the Texas Parks and Wildlife Department)

The Nature Conservancy’s Sustainable Waters program, designed to protect river ecosystems downstream of dams, has sponsored workshops at Caddo Lake to determine the research needed to develop ecologically based environmental flow recommendations for the lake. Environmental flow is the amount of water that needs to flow down the river to maintain the ecological system in the lake, river and flood plain.

“The effort under way is a science-based approach to determining exactly how much water is really required and under what conditions for the downstream environment to persist over time, while continuing to provide quality habitat for associated flora and fauna,” said Dan Weber, the Conservancy’s northwest Louisiana program manager.

Texas A&M researchers present at workshop

At the first workshop, Texas A&M researchers presented a summary report that synthesized the “state of knowledge” about the geography, hydrology, ecology and environmental impacts affecting Caddo Lake and Big Cypress Creek, said Wildlife and Fisheries Sciences professor Kirk Winemiller.

Other A&M scientists involved in the workshops were Brad Wilcox, associate professor of rangeland ecology and management, who examined the hydrology; Anne Chin, associate professor of geography, who studied the fluvial geomorphology; and Dan Roelke, associate professor of wildlife and fisheries sciences and oceanography, concerned with nutrients, productivity and aquatic plants. Steve Davis, assistant professor of wildlife and fisheries sciences, studied the riparian and floodplain vegetation, and Winemiller studied the aquatic and terrestrial fauna.

Strategies developed and implemented

Winemiller said workshop participants developed “building blocks,” describing the expected ecological responses or conditions associated with specific river flows or lake level fluctuations for Big Cypress Bayou and Caddo Lake. Winemiller said the participants came up with preliminary recommendations for researching environmental flows as well as research to fill information gaps and to improve estimates.

A critically important next step involved developing a plan for conducting necessary baseline monitoring of ecological conditions in Big Cypress Bayou in 2005 and implementing Big Cypress Bayou low-flow and high-flow management strategies, beginning in 2006. In addition, the feasibility of modifying the Lake O’ the Pines outlet to improve control of lake levels, nutrient flows and cypress regeneration was discussed.

A research coordination network for Caddo Lake will regularly call for and coordinate field research by key agencies, scientists and stakeholders to establish an ongoing process known as adaptive management that will respond effectively to environmental changes.