Image courtesy of NOAA
Editor’s note: this article was written by Ray Stewart, President of Ohio Wetlands Association and Dr. William J. Mitsch, Professor Emeritus, The Ohio State University; Director, Olentangy River Wetland Research Park, OSU; Eminent Scholar and Director, Everglades Wetland Research Park; Founding Editor-in-Chief, Ecological Engineering
Officials may be hedging their responses to the latest water crisis in the western Lake Erie basin but there is no mystery to what is going on. While the investigation into specifics about this particular spike have not been completed, the general causes are well understood.
Too many nutrients, especially phosphorus, have made their way into the water. Agricultural fertilizers, septic systems, sewage treatment plants and concentrated animal feeding operations (CAFOs) are all contributors. These nutrients, combined with the long day lengths and the warmer temperatures of summer, create the perfect incubator for algae and especially Mycrosistis cyanobacteria that produce toxic substances.
Although climate change exacerbates the conditions that enhance Mycrosistis production, other man-made landscape alterations have been leading up to this moment ever since the first settlement of Europeans in the region. Among the most egregious alterations in the western Lake Erie basin was the clearing and draining of the Great Black Swamp more than 100 years ago. The conversion of wetlands to agriculture and urban settlement required a monumental effort to move water rapidly off the land. Drain tiles in farm fields, ditches, sewer networks, and hard surfaces manage the water on nearly every acre throughout the watershed. Straightened and shortened creeks and streams send the water and all that it carries into major river systems and to Lake Erie.
The science is clear and the solution to the nutrient stimulated harmful algae blooms (HAB’s) is well known. There are three facets to correcting the problem. One is local, for individuals to do their part to stop the excess use of fertilizers, maintaining septic systems and cleaning up after their pets. The second is industrial in scale, for businesses, farm operators and municipalities to assure that they do not allow nutrients or any other contaminants to get into the waterways. Third, restore natural habitats that will prevent nutrients from getting into the waterways and restore those habitats that naturally filter water and remove those nutrients that lead to HAB’s.
The natural habitat that is best suited to the solution of HAB’s is wetlands, the habitat that used to dominate the landscape around the western basin of Lake Erie. Water must be slowed down, held back, kept from entering the rivers that lead to Lake Erie as long as possible. Runoff from fields should pass through vegetated treatment or retention wetlands before entering public waters. Our creeks and streams need to twist and meander through the landscape and expand onto floodplains to absorb surges after rains. The reversal of decades of civil engineering to ecological engineering and the restoration of natural wetlands will serve to restore this vital public resource, water, essential to the life and well-being to millions of residents who depend on the waters of Lake Erie. Our Ohio Wetland Association can help. We know how wetlands work and how much fertilizer they can adsorb on a sustainable basis. There are examples of successful systems in Ohio, Florida, and elsewhere that have been operating for decades.
Ohio Wetlands Association recommends the restoration of a large percentage of the Great Black Swamp and lacustrine wetlands along the Lake Erie Coast as buffers between the agricultural field and Lake Erie. The benefits of this restoration go beyond the HAB issues addressed in this article. Healthy wetlands will assure a healthy Lake Erie and better Ohio. There are many other ecosystem services that these wetlands will provide including wildlife and waterfowl habitat, carbon sequestration, and places for humans to learn about how our ecosystems function.