MAUMEE – How does one dispose of an annual 1.5 million cubic yards of dredged sediment in an economically and ecologically feasible way, now that dumping it into Lake Erie was officially banned last year?
The potential answers were discussed at the March Agribusiness Forum hosted by the Center for Innovative Food Technology and held virtually.
The presentation “Value and Benefits of Dredge Sediment on Farm and Agriculture Lands in Northwest Ohio” allowed speakers Vanessa Steigerwald-Dick of the Ohio EPA and Dr. Angelica Vazquez-Ortega, Bowling Green State University department of Earth, Environment and Society assistant professor, to share the most current research findings.
Steigerwald-Dick first explained the size and importance of the annual dredging program. She said each year 35 million tons of commodities move through the Lake Erie system, resulting in $25 billion in business revenue and 130,000 jobs.
As a result, she said, it has always been imperative to keep Ohio’s Lake Erie harbors and shipping channels open so that commodities can move in and out of the ports. Historically, most of the dredged material was disposed of in Lake Erie’s open waters but it was found that adding large amounts of sediment and nutrients to the water was seriously impacting water quality.
To meet the challenge of disposing of the dredge material, several agencies came together to find safe, beneficial uses for harbor sediment with the goals of increasing use of the dredge material to create an economic value, while at the same time improving water quality by reducing nutrient impacts and sedimentation that dredge material creates when dumped in open waters.
Steigerwald-Dick said the State of Ohio is working closely with the U.S. Army Corps of Engineers and local stakeholders to develop projects to beneficially use dredged sediment as a resource.
Toward those ends, during the 2020 dredging of Toledo Harbor, 635,000 cubic yards of dredge material was hydraulically unloaded into the Port Authority’s recently upgraded Facility 3. The Toledo-Lucas County Port Authority, using Healthy Lake Erie Funds, constructed the Dredged Material Center of Innovation to establish a model demonstration site for beneficial use of dredged sediment research, provide innovative edge of field research for agricultural runoff impact reductions and provide soil blending opportunities for beneficial use of dredge material.
Located on the western bank of the Maumee River, the 10-acre site was filled with 70,000 cubic yards of dredge material from Toledo Harbor in 2016 and 2017.
Steigerwald-Dick said it is planned that the de-watered dredge material will become available for beneficial use projects such as marketable soil and soil amendment for farm fields.
However, before that could happen, studies were needed to ensure that the dredged soil was suitable for uses such as farm fields.
Representative samples of dredge material were collected for laboratory testing for agronomic and geotechnical parameters to see if the dredge had the same nutrient levels as standard soil and no accumulation of toxins ranging from heavy metals to toxins created by harmful blue-green algae blooms which have plagued Lake Erie for years.
One such study was presented by the second forum speaker, Vazquez-Ortega.
In a series of experiments, she determined that dredge material would be suitable for agricultural use and contained nutrient levels sufficient for most Northwest Ohio crops.
To reach her conclusions, she conducted an experiment on the growth of soybeans grown in samples of soil from dredge material as well and standard soils in a greenhouse setting. In her research she found that there was no discernible differences between soybeans grown in dredge material and regular soil, although she did note the soybean roots were more dense in the dredge material.
As to introduced toxins in the dredge material, she found no evidence of toxins from blue-green algae nor accumulated heavy metals. Concerning chemical properties, only calcium appeared lower in the dredge samples. Dredge samples consistently had higher organic matter.
But, now how to translate these findings to the larger goals?
Steigerwald-Dick said that stepping into the picture is the Ohio Lake Erie Consortium, which soon will be accepting Requests For Proposals specifically looking for a demonstration project on the side-by-side comparison of crop yield between two adjacent farm fields, one of which would be amended with Toledo Harbor dredge material by the successful applicant.
The application of Toledo Harbor Dredge Material Demonstration Project can be found at https://lakeerie.ohio.gov/wps/portal/gov/lec/home/resources/dredgerfp_2021.
CIFT has hosted Agribusiness Breakfast meetings for 12 years as an in-person event. Pandemic restrictions moved the meetings online in 2020. They plan to returning to in-person meetings when restrictions are lifted.