Introduction: A New Phase in Lake Research
After more than a year of planning, our team is launching a pivotal phase of field research on Lake Decatur. We have designed and built two small floating wetlands, or living laboratories, that will drift on the lake’s surface. These rafts are more than static installations; they are dynamic platforms for investigating how floating wetlands influence nutrient levels and sediment movement across lake systems nationwide.
Design: The Structure and Purpose of the Rafts
The living laboratories consist of simple steel cages loaded with thick coils of coir, a natural coconut fiber. The coir acts as a stable matrix to hold a diverse array of native plants in place while allowing water to flow through and around the roots. At the dock, researchers arrange nine species of native vegetation in carefully planned rows within the coir, ensuring each plant has room to establish and interact with the water column.
The placement is deliberate rather than random. Last September, we harvested plants from nearby wetlands and tested them in the Ecohydraulics and Ecomorphodynamics Laboratory at the University of Illinois to determine root toughness under flow and potential effects on lake-bottom sediments. Those lab findings guide today’s planting strategy, aiming to maximize root protection in higher-flow conditions and to enable clear identification of each species in future analyses.
Construction and Safety: Getting the Wetlands Ready for Lake Life
Once the plants are anchored in the coir logs, we attach bright orange buoys to the frames to alert boaters. A small fence around each raft helps deter hungry geese and protects the tender roots from herbivory. The rafts themselves are straightforward steel structures without a walking platform, designed solely to support plant growth and future data collection as the ecosystem responds to the engineered habitat.
Deployment: From Dock to Deep Water
With a shared sense of accomplishment, the team lifts and lowers the floating wetlands into the water. The moment of release is followed by careful checks: the rafts float at the planned depth to ensure the roots remain submerged and active. Archimedes would approve—the buoyant force aligns with the expected weight and draft of the plant-filled logs.
Next, the team navigates to the anchorage site. A boat tow to the planned location is longer and slower than anticipated due to the raft’s buoyancy and surrounding buoys, transforming a quick transfer into a cautious, meandering voyage. Upon arrival, the anchorage and orientation are assessed, and minor adjustments are made after a quick survey of conditions.
Monitoring and Early Data: What We Expect to Learn
In the coming weeks, the plants will grow, and their roots will gradually penetrate the coir and extend into the water column. This root development will enable us to begin testing key hypotheses: How do root systems interact with lake currents and suspended sediments? Do floating wetlands reduce erosion in the littoral zone or alter deposition patterns on the lake bottom? And what habitats might these rafts foster for aquatic organisms along the margins and nearshore areas?
Why It Matters: Implications for Lake Management
Floating wetlands offer a potentially scalable approach to improving water quality and shaping sediment regimes in lake systems. By carefully selecting native plant species and arranging them in row plots, researchers can isolate the effects of plant structure on sediment capture, nutrient uptake, and microhabitat creation. The insights gleaned from Lake Decatur could inform similar efforts across regional and national water bodies facing nutrient loading, algal blooms, and shoreline erosion.
Looking Ahead
As the project progresses, researchers will monitor plant health, root expansion, and sediment interactions, integrating field observations with iterative modeling. The ultimate aim is to build a robust, transferable framework for floating wetlands as living laboratories—spaces where science and restoration can advance together to protect and restore lake ecosystems.
