A severe heat wave and drought had caused trees to prematurely turn orange and gold on the shores of Otter Lake on the first day of August. But a cool breeze blew as Dennis Ross and Jeff Boeckler skimmed across the surface in a pontoon boat, toward a strange-looking contraption with a blue heron sitting imperiously upon it. The apparatus is one of the measures the Otter Lake Water Commission has employed to fight the serious nutrient pollution problems that affect many Illinois lakes and waterways, causing algae blooms that are disgusting and can be toxic; nitrates that can dangerously contaminate drinking water; and low oxygen zones that harm fish and other aquatic life.
Four of these solar-powered machines protrude above the water in Otter Lake, each with mechanical arms that revolve to stir the water and impede the growth of algae that thrives on the nutrients nitrogen and phosphorus. Nitrogen and phosphorus are major components of the fertilizer that farmers put on their fields throughout the Midwest, including around Otter Lake about 35 miles south of Springfield.
Much of the fertilizer runs off during rain, heading toward the lake. Extremely hot summers – like this one in 2012, expected to become more common with climate change – exacerbate the effects of nutrient pollution because algae thrive in hotter conditions. Drought also makes nutrient pollution worse, since lower lake levels mean pollution is more concentrated. And even though there is less runoff during a drought, when it does eventually rain, the runoff can be worse because water skims over hot dry ground rather than percolating into the soil.
The Dangers of Nutrient Pollution
Many “lakes” surrounded by agricultural fields in Illinois are actually drinking water reservoirs, so nutrient pollution is a serious economic and health problem. Nitrogen in the water can mean high levels of nitrates, which can cause a dangerous condition called “blue baby syndrome” wherein babies’ red blood cells are not able to take up enough oxygen. Nitrates are also linked to thyroid problems, including cancer, in adults. Meanwhile, nitrogen and phosphorus fuel blooms of toxic blue-green algae, or cyanobacteria, which can cause a range of illnesses in humans and animals.
In 2005, the Illinois Environmental Protection Agency (IEPA) surveyed 15 lakes statewide and found toxic algae in 13 of them. A 2010 national lakes assessment by the U.S. EPA similarly found that 18 out of 21 Illinois lakes surveyed had seriously elevated levels of nitrogen and/or phosphorus; and 12 of the lakes had indicators of toxic algae.
Along with serious health risks, algae often gives drinking water a foul odor and taste. “A glass of water tasted like you were drinking out of a flower pot,” said Ross of a 2006 algae outbreak in Otter Lake. But treating algae-infested drinking water creates its own risks, creating byproducts linked to higher rates of cancer and asthma, as detailed in an April 2012 report by the Environmental Working Group.
Algae blooms can also make recreational boating, fishing and paddling unpleasant or even impossible. In 2006, Otter Lake had to cancel a cardboard boat regatta because of algae blooms.
When algae decompose, they consume oxygen and lead to oxygen levels so low it is hard for fish to survive. This is of course a problem for anglers, as are long filaments of green algae that get stuck on their lines.
People have known for a long time about the serious consequences of nutrient pollution. But reducing it is not easy. Federal and state laws regulate releases from power plants, factories or other point sources into water bodies. But there are no regulations regarding runoff from farms.
What Can Be Done
Many farmers are taking the initiative to reduce the amount of fertilizer and sediment washing off their land. Doing so not only reduces pollution to nearby waterways, but also keeps the valuable soil and fertilizers where they are needed – on the farm.
Water commissions and environmental groups are partnering with farmers by helping them secure grants, providing technical advice or even coordinating projects for them. For some years, the Otter Lake Water Commission, with assistance from Boeckler’s Northwater Consulting Group, has received federal grants specifically to reduce nutrient pollution. The grants, under Section 319 of the Clean Water Act, provide matching federal funds for projects including the construction of ponds, wetlands, dry dams and rock riffles to catch and absorb runoff before it gets into lakes or streams.
Enter Farley Cole, a long-time local farmer who grows soybeans and corn and raises cattle on his own fields and land that he manages for other owners adjacent to Otter Lake. He and other farmers got involved with water quality issues in the early 1990s when they learned about high levels of the toxic pesticide Atrazine in the drinking water.
On an extremely hot July afternoon, Ross, Boeckler and Cole drove trucks between Farley’s rows of corn, shriveled and yellow because of the drought. Runoff has cut a steep channel through this earth. During rains, rushing water courses down the incline and picks up loads of dirt, emptying much of it into Otter Lake. Sedimentation – the deposit of dirt – in lakes is a serious problem throughout the state, especially since phosphorus binds to sediment. But this gulley in Cole’s land is now filled with white limestone boulders that catch sediment and break the speed of water flowing through.
Cole paid 20% of the cost of this project, while the federal government grant covered 60% of the cost and the local water commission the remaining 20%. Similar grants also allowed Cole to build a wetland and several ponds on his land. The ponds provide a water source for cattle and catch sediment that can later be dredged and spread – as rich soil – on fields.
“These guys are out there farming – it has to make financial sense to them or they can’t do it,” Ross said. So far the commission has worked with about 15 farmers, and they count on word of mouth from people like Cole to convince others to participate. Gaining farmers’ trust isn’t always easy, especially since some are still bitter from losing land for the creation of the reservoir in 1969.
Cole noted that he sacrificed having two head of cattle to make room for the wetland, but he knew it was the right thing to do. “I guess we’re saving our soil and keeping it on our land instead of putting it in your lake,” he told Ross.
Even the best land management practices will never curb all runoff, so Boeckler and Ross also fight nutrient pollution by fortifying the shores of Otter Lake. Motoring around on the pontoon, they pointed out the attractive perimeter of white limestone, from a local quarry, that lines much of the shore. Boeckler has specifically calibrated the size and shape of the rocks to absorb the impact of waves and wind, preventing the otherwise soft shoreline from eroding.
Erosion means a massive influx of sediment and nutrients – dirt and fertilizers – into the lake. The limestone barriers, by contrast, allow rich soil to build up on the shore, supporting native plants whose roots stabilize the soil and further prevent runoff and erosion.
The Otter Lake Water Commission covered about a mile of the shoreline with limestone this summer. Federal grants have also helped Boeckler and Ross remove masses of invasive honeysuckle from the banks. Honeysuckle proliferates and out-competes other plants, then forms a thick canopy that blocks sunlight and prevents smaller plants from growing. With the honeysuckle gone, you can already see new native plants growing, including bald cypress planted by the water commission.
Different Lake, Same Problem
Like Otter Lake, Lake Bloomington 90 miles to the northeast is also a drinking water reservoir and a very popular recreational oasis – and sometimes a hotbed of algae and nutrient pollution.
Sitting at a picnic table beside Lake Bloomington on a balmy July weekday evening, Bloomington Water Purification Superintendent Rick Twait watched boaters and fishermen enjoy the peaceful waters – by the weekend the lake would be packed – and explained graphs showing nitrate levels in the lake and tributaries over a quarter century.
In 2005, Lake Bloomington had critical amounts of toxic blue-green algae called oscillatoria. Twait attributes the problem to hot dry September and October months, followed by heavy rains in November – a situation water managers fear could be replicated in fall 2012.
There are legal limits on the amount of nitrate that can be in drinking water, and Lake Bloomington periodically exceeds them. Equipment to remove nitrate is extremely expensive – the Environmental Working Group estimates $12 million to $56 million for a town of 100,000. Nitrate levels were especially high during the drought of 1988 and 1989.
Another drought period like that would mean serious and costly measures to remove nitrate from the drinking water, like reverse osmosis or ion exchange. Twait notes that ion exchange purification involves flushing water and chloride ions through a brine solution, creating the need to dispose of a toxic brine byproduct.
When nitrate levels spike, Lake Bloomington water is typically mixed with water from nearby Evergreen Lake – a larger reservoir that drains a much smaller area, so nutrients are more diluted and less of a problem. But such mixing isn’t a permanent solution, especially if droughts become more common. It would be much more efficient and ecologically responsible to prevent too much nitrogen from getting into the lake in the first place.
As the Environmental Working Group says in its recent report, “Treating this water after the fact to clean up the contamination is increasingly expensive, difficult and, if current trends continue, ultimately unsustainable.”
Keeping Nutrients out of Lake Bloomington
Currently, the Bloomington water department is working with groups and other agencies, including The Nature Conservancy and the Environmental Defense Fund, to promote better nutrient management practices, including developing wetlands and rock riffles on surrounding farms. When nitrogen is trapped in a wetland, it breaks down to a harmless nitrogen gas that is released into the atmosphere. Phosphorus by contrast does not dissipate, but can be sequestered in wetlands or soil.
Runoff into Lake Bloomington can be reduced by removing the “drainage tiles” – plastic pipes planted under much of Illinois’ farmland – that were originally intended to drain swampy earth. Now many people see the tiles as counter-productive, since they collect and channel water into nearby water bodies, rather than letting it naturally soak into the soil.
The Bloomington water department and The Nature Conservancy are testing different types of nitrogen removal on six 5-acre test plots. They are also encouraging farmers to do more of their fertilizing in the spring than the fall, when rains washing over semi-frozen ground create especially bad runoff problems. They use aerial photography, digital precision tools and testing nitrogen levels in cornstalks to help farmers figure out the optimum amount of fertilizer to use.
“Farmers love it. It doesn’t do them any good to spend all this money and have it all drain off,” Twait said. “They do have a very good stewardship ethic.”
The water district has been working with local landowners since the 1990s, but their efforts are still in the relatively early stages and based on county and local funding rather than federal programs. Twait noted that it can be expensive and time-consuming for farmers to change their practices or convert fields to wetlands. But it is in everyone’s interest to solve the problem of nutrient pollution.
“We’re trying to deal with the economic realities,” Twait said. “They’re providing an essential commodity – food. But we are providing a water supply. We have to deliver, and it better be good.”