Protecting our Beaches by Restoring Natural Ecosystem Processes
Maumee Bay State Park has had to post swim advisories at its lakeside beach for several days a year due to high levels of bacteria and algae. Dr. Daryl Dwyer, a University of Toledo associate professor and director of the Environmental Remediation and Restoration Laboratory at the Lake Erie Center, his students, and U.S. Geological Society collaborators identified the Wolf Creek watershed in Oregon as a proximal source of nutrients (that contribute to algal blooms) and bacteria for the beach. Armed with these data, Dr. Dwyer obtained funding from the U.S. Environmental Protection Agency via the Great Lakes Restoration Initiative to create pilot projects that are designed to restore watershed habitat to reduce the influx of nutrients and bacteria.
Although the emphasis has been on keeping bacteria and nutrients from entering our watershed, this is not the only solution according to Dr. Dwyer. “Continuing to develop best practices in agriculture is important, but our goal with this project is to demonstrate that capturing bacteria and nutrients by restoring native habitat is a valuable strategy.”
Part of the restoration process resulted in an in-stream pond, which has been operating since August of 2014. Ph.D. student, Ryan Jackwood, and M.S. student, Matthew Mayher, are documenting the effect of the pond on water quality. To date, they have observed reductions that are better than expected:
Total suspended solids – average daily reduction: 57%
Densities of bacteria – average daily reduction: 93%
Phosphorus concentration – average daily reduction: 49%
The in-stream pond is effective because bacteria and phosphorus are often attached to suspended sediment. Water velocity slows as it enters the pond, which causes bed sediment and heavier particles to sink to the bottom of the pond. All of the nutrients and bacteria that were attached to these particles become trapped within the accumulating sediment. Water that exits the pond contains less sediment and consequently less nutrients and bacteria. Over time, bacteria will die and the nutrient-rich sediment will be dredged periodically and applied to agricultural fields.
Within a 10-acre footprint at the Maumee Bay State Park a wetland system was created as the second component of the habitat restoration project. Construction and the inclusion of native plant species to the site were completed in early spring, 2015. Measurements to observe the effects on water quality are now underway. However, Mr. Jackwood and Dr. Dwyer are confident that the design will prove to be a useful model for lake shore water quality treatment. Whereas the pond design relies on sediment sinking to the bottom of the pond, the wetland design uses a soil-rock substrate as a filter to remove bacteria and nutrients that are not attached to larger particles moving through the creek. Thus, the restoration project results in a two-pronged attack on pollutants. First the heavier particles are removed and then the finer particles and dissolved nutrients are removed. In 2015, the UT researchers hope to document improvements in beach water quality. You can follow potential improvements by logging into the NowCast System for Ohio beaches: http://www.ohionowcast.info/
Water will be pumped through the wetlands which traps contaminates, dissolved nutrients, and free-floating bacteria within the soil-rock substrate. Native plants use the nutrients for growth and naturally break down several types of contaminants.