Over the last 3 years, Merrill Creek Reservoir (MCR) has been committed to finding ways to perform conservation work that has multiple ecological benefits and, in some cases, those conservation practices can simultaneously provide added value to recreational uses of the property. This is especially highlighted by MCR’s work to improve fish habitat and fishing opportunities at MCR. Specifically, MCR’s use of harvested logs from ecological forestry projects to create Fish Crib Structures and the use of invasive/non-native autumn olive plants removed during annual meadow management projects for building Fish Spider-Block structures to create artificial reefs in the reservoir. As these submerged structures are providing physical cover and over time plant and algae growth on them attract macroinvertebrates, the structures become a refuge area for smaller fish to forage, spawn and seek cover from larger fish.
MCR Volunteers Planting the Floating Wetlands
Recent surveys over the summer of 2025 of these structures that have been deployed in the reservoir have shown that a variety of fish are using them as intended, including Yellow Perch, Black Crappie and both Small and Large-mouth Bass!
As success of the submerged fish structures (a “bottom-up” method of structure) progress, MCR has now deployed, with the help of the MCR Volunteer Group, a new type of habitat structure in the reservoir that concentrates on a “top-down” process of providing fish structure with other ecological benefits. Specifically, MC has deployed five (5) floating wetlands clustered together in the cove near the shoreline of the Wildlife Viewing Blind located off the Blue Trail in the Preserve Area.
Floating Wetland Functionality
Floating wetlands are buoyant structures, or “islands”, planted with vegetation that floats on the surface of the reservoir. They are tethered to anchors, but their buoyancy allows them to adapt to changing water levels. Typically, these structures are used in smaller bodies of water to help improve water quality by absorbing excess nutrients (such as phosphorus and nitrogen) and other pollutants. However, with MCR being a 650-acre reservoir that holds 16-billion gallons of water, nutrient uptake by the vegetation on these structures, although happening, is not expected to show any kind of measurable impact. However, what is expected of these floating structures is they will provide additional habitat for fish and other wildlife.
Basically, the structures provide shade areas for fish, but the real magic is that the roots of the native vegetation that is planted on the structures grow hydroponically into the water, creating a root-biofilm network that not only filters water from sediment and provides a surface for microbes that further process the breakdown of any nutrients, but they create a unique complex habitat for beneficial insects, fish, and other aquatic life, thus contributing to biodiversity. They also create areas for turtle basking, and amphibian and bird foraging/resting.