Neal Marsh is WRI’s first mitigation bank which took place on property that it solely owns. The property was acquired by a donation and sale between William Anest, the property’s previous owner and Robert “Bob” Neal, then President of Wetlands Research Inc.
Historically, the parcel was used for a golf course and a paint-ball battlefield. The property was purchased to expand the restored wetlands along the Des Plaines River floodplain, providing additional ecosystem services such as flood storage and habitat as well as additional research opportunities.
Neal Marsh has a unique mitigation bank design, as a rock riffle installed in the Des Plaines River was used to restore the hydrology back to the adjacent floodplain within and extending beyond Neal Marsh. Since its installation, Neal Marsh mitigation bank has evolved into a high quality aquatic resource, providing nesting and foraging areas for waterfowl and migratory birds dependent on wetlands and water features but also for frogs, snakes, turtles, spiders, bees, butterflies, and other aquatic insects. Additionally, larger mammals such as beaver, muskrat, coyote, and white tailed deer use the area for bedding and foraging.
The stream ecology and fish habitat have improved; the upstream reach of the Des Plaines River has reduced flows, allowing for sediments in the water to drop to the channel bottom. Light penetration increased and plants have begun to colonize the channel, utilizing nutrients (especially phosphorus) which is adhered to soil-sediment particles. Past studies at the Des Plaines River Wetland Demonstration Project Research Station proved that wetlands can remove on average 60% and 80% of the phosphorus and nitrogen load respectively. Concurrently, the bowfin and other sight feeding fish species populations increased, decreasing the number of carp found in the Des Plaines River, thereby improving water quality, yet another crucial function of wetlands. Today fish migrating from southern reaches traverse the rock riffle and add to the diversity of fish species found in the reach of stream where once 90% of the fish biomass was comprised of common carp.
Currently, we are pursuing a study to investigate the use of geothermal heat to maintain surface water temperatures above freezing in Neal Marsh during the months of December through March. This should promote the processes of denitrification and phosphorous sequestration. If successful, the widespread application of these aquatic ecosystems could help control the size of the hypoxic zone in the Gulf of Mexico and reduce algal blooms upstream in the Mississippi River and its tributaries. We use the term GTWetlandsTM to identify such ecosystems and their enhanced functions.