Artificial wetland in Ohio filters runoff, fights algae

Ohio officials have built an artificial wetland to help prevent blooms of toxic algae in Grand Lake St. Marys by filtering runoff from a nearby creek.

The Ohio lake located about two and a half hours southwest of Lake Erie has been a hotspot for toxic algal blooms over the past few years.

The artificial wetlands and water treatment facilities at Prairie Creek began filtering water entering Grand Lake St. Marys in June 2013.

The artificial wetlands and water treatment facilities at Prairie Creek began filtering water entering Grand Lake St. Marys in June 2013.

Excess nutrients in water runoff are a leading cause of harmful algal blooms, a sudden growth of toxic algae that significantly reduces the supply of oxygen to marine organisms. Algal blooms have been a growing cause of concern in communities all over the country, notably in the Great Lakes region, where nearly 45 percent of all the reported incidents occurred this summer.

“It didn’t happen overnight, and it won’t be fixed overnight,” said Ohio Department of Natural Resources spokesperson, Mark Bruce. “This is part of a multifaceted operation to improve the health of water. Our end goal is to not have algae blooms in Grand Lake St. Marys.”

Construction of the 200-acre project started in the spring of 2012, said Milt Miller, manager of the Grand Lake St. Marys Restoration Commission. Operation of the Prairie Creek site began in June of this year.

About 1.3 million gallons of Prairie Creek water is pumped each day through an alum dosing station, settlement ponds and wetlands.

Alum is a binding agent that weighs down excess nutrients as the water travels through the settlement ponds. It is used to supplement the natural filtering process done by the plants in the wetlands.

“Wetlands are mother nature’s way of filtering water. They are nature’s kidneys,” Bruce said.

“The wetland was doing such a good job by itself that we didn’t start using alum until a few weeks ago,” said Miller. “With fall coming on, you have a shorter growing season, and the plants weren’t taking up the phosphorus.”

The idea is to catch as much of the nitrogen, phosphorus and dissolved reactive phosphorus as possible before they enter the lake. Each of these is a contributing factor to harmful algal blooms and increase in toxic cyanobacteria, but the third is of particular concern.

Dissolved reactive phosphorus always comes from commercial fertilizer, according to Miller.

Water is discharged from treatment facilities into artificial wetlands, where many excess nutrients are filtered out before entering the lake.

Water is discharged from treatment facilities into artificial wetlands, where many excess nutrients are filtered out before entering the lake. Photo: Grand Lake St. Marys Restoration Commission.

“Soil carries phosphorus binded to it to the lake. Dissolved phosphorus actually comes in the water.”

Prior to when alum dosing began, data was collected by the Grand Lake St. Marys Restoration Commission of the amount of these nutrients going into and out of the system. Since June, nitrogen levels going into the lake from the Prairie Creek watershed have been decreased by an average of 41 percent. Additionally, dissolved reactive phosphorus output has dropped an average of 65 percent, and phosphorus outputs have dropped almost three-quarters. Numbers since alum dosing began will be collected in the coming weeks.

Plans for an additional 40-acre treatment train at neighboring Coldwater Creek have also begun. Though there is not a yet an exact time table, the Grand Lake St. Marys Restoration Commission would like to have it functioning by the early summer of next year.

The artificial wetland was officially dedicated on Oct. 1st by the Ohio Department of Natural Resources, Ohio Department of Agriculture and the Ohio Environmental Protection Agency.

  • Tyler

    The Lake has a multitude of problems and blaming one group of people is wrong. First off the lake is way too shallow, it was meant to be drained constantly to feed the canals. Second there is runoff on farms and farmers are changing their ways and doing a better job, however, all the manure barns that are put up are pointless because when march comes around everyone and their brother are hauling manure and when a two inch down poor comes around, everything is washed into the creeks. Finally the marshland around the lake was not all destroyed by just farmers. People have to think about all the housing, camping, and channels that built right by the lake. The channels hurt the lake greatly because the water is stagnant and algae loves stagnant water because the particles settle down allowing sunlight to penetrate and the algae to grow.

  • Tom M.

    Well folks a wetland replacement or natural has to be wet to work.

  • Patty

    In response to Vicki, unfortunately Buckeye Lake is also starting to have an algal bloom problem. They had to shut the beaches this year because the Alge was too high for individuals to safely swim.

  • Joe

    The requirement of a “tricked out” drainage ditch for farmland would seem to indicate a misplaced farm.

  • Mary

    Over 90 % of the wetlands in Ohio have been destroyed by Agriculture. The Lake Erie watershed is home to many CAFOS and yet this author would like us to believe it is the row crop farmer creating the pollution. Be real, I think this is ludicrous. How about placing the blame where it belongs on the improper placement of CAFOS in the environmentally suspect area! Does anyone blame Farm Bureau for this?Larry Antosh should know better! Fake wetlands do not work! Get real and address the issue scientifically, there are plenty of reources out there.

  • Anonymous

    Ohio has destroyed 90% of the wetlands by allowing agriculture to plow them up and plant on them. In the western part of Ohio where CAFOS are permitted to build in the Lake Erie watershed are we to believe it is the row farmers creating the algae? Nada! Get real and address the problem realistically Farm Bureau! Do you really think you can improve on what God created?

  • Bob Midden

    It’s interesting that Mr. Milt Miller is quoted in this article as saying that dissolved reactive phosphorus (DRP) always comes from commercial fertilizer. I agree that commercial fertilizer does produce DRP but we always find high levels of DRP in manure samples that we test in my chemistry lab at Bowling Green State University using a Seal Analytical AQ2+ discrete chemical analyzer and standard sampling and US EPA testing protocol. We also find high levels of DRP in water after it passes through mixtures of soil and manure in the lab. And we have measured very high levels of DRP in runoff from agricultural fields to which manure has been applied prior to heavy rain. So I am curious about the basis for Mr. Miller’s statement and wonder if perhaps it was misquoted or I am misinterpreting it or there is some scientific information that I have not previously encountered to support this claim. (We also find DRP in water coming from municipal waste water treatment plants especially during CSOs and household septic systems that are not fully functioning.)

  • Vickie

    I was very surprised to read this statement – “Dissolved reactive phosphorus always comes from commercial fertilizer, according to Miller.” I think it’s interesting that GLSM is surrounded by animal production operations and the Lake is full of algae. Whereas, Indian Lake is located approximately 30 miles east of GLSM and is surrounded by row crop fields BUT it hasn’t had algae problems. I don’t understand why they are trying to place the blame on row crop farmers and commercial fertilizer. I wonder if that’s the only way they can get state money for band-aids?

  • Marty

    Glad to hear the created wetland is working so well, and significantly improving water quality. Have there also been strong efforts to reduce the nitrogen and phosphorus inputs from agriculture? Thanks.