With so much focus on agriculture as the source of excess nutrients in Lake Erie, it seems like the challenges associated with what to do about large quantities of dredging material being dumped into the Maumee Bay have been comparatively ignored.
Well, if it was being ignored as a part of the problem, it is not any more. Around 800,000 to 1 million cubic yards of dredge material collected to keep the Port of Toledo clear is dumped into the open lake each year. There the material is re-suspended in the water where it can potentially provide nutrients to harmful algae.
The challenges of dredge material were addressed under Senate Bill 1 that was implemented this summer. The bill bans the disposal of dredge material into Lake Erie in Maumee Bay after July 1, 2020 unless authorized by the director of the Ohio EPA.
In addition, there is some experimental work being done in Toledo to better learn how to handle the challenging material.
“At the Port of Toledo there is a 16-acre site which we’ll be doing construction work on this fall,” said Scudder Mackey, chief at the Office of Coastal Management with the Ohio Department of Natural Resources. “We are going to create four cells where we are going to perform experiments using dredge material in terms of its suitability for agricultural use. We are going to try to manage the water in this sediment in a better way and also see if we can get the types of material that that ag community would be interested in. We think that taking material from the lake that came off the fields and placing it back on the land could be the most common sense thing to do.”
The material that is dredged is largely comprised of potentially agriculturally valuable soils.
“Typically the sediments coming down the Maumee River are very fine grained clays and silts. Phosphorus and nitrogen are often bound with that sediment,” Mackey said. “We are concerned about those nutrients, but we are also concerned about the sediment loading as well. We are talking about perhaps 70,000 cubic yards being placed initially in these experimental sites. This is a very small percentage of the total dredged material, but if we find larger areas to place this material we could reduce the amount of material we are putting into Lake Erie by a significant percentage and it could be used for agricultural applications. We need to learn to treat dredged materials as a resource not a waste product.”