“Our state is one of the highest contributors of nitrogen and phosphorus to the Gulf of Mexico. That means the Bloomington Drinking Watersheds project doesn’t just benefit local residents; it has the potential to positively affect the hypoxia or 'dead zones' in the Gulf of Mexico. ”
– Dr. Maria Lemke, Aquatic Ecologist for The Nature Conservancy in Illinois
When the growing season began this spring, a total of four new constructed wetlands bordered agricultural lands near Bloomington, Illinois, with two more in the design phase. That’s good news for the 80,000 people who rely on Lake Bloomington every day.
Lake Bloomington is one of two reservoirs that provide the city with drinking water, and it’s surrounded by lands that are 80-90 percent farmed and drained by surface channels and subsurface tiles. When water leaves the fields and enters these drainage systems, it brings with it the nutrients used in fertilizer, such as phosphorus and nitrogen. These nutrients eventually enter Lake Bloomington through tributaries like Money Creek and Six Mile Creek.
As a result, Lake Bloomington has historically exceeded the Environmental Protection Agency’s drinking water standard of 10 mg/L of nitrates. High concentrations of nitrogen can cause large algal blooms that lead to taste and odor problems in drinking water and, in some cases, may be associated with blue baby syndrome -- an illness that arises when an infant’s blood is unable to carry enough oxygen to body cells and tissue. Nitrogen-laden waters can also distress fish and other animals and has been reported to contribute to gulf hypoxia, also known as the “dead zone,” in the Gulf of Mexico.
For the past several years, The Nature Conservancy and partner organizations have been working with the City of Bloomington towards a way to use nature to solve Bloomington’s drinking water problems. Together, they are collaborating on a “constructed wetlands” program along Money Creek and Six Mile Creek that includes using a combination of wetlands and nutrient management to reduce nutrient loss from farm fields to the streams.
“We are working with partners to leverage private funding and Farm Bill programs to help farmers construct small wetlands that intercept and reduce nutrient run off,” explained Maria Lemke, a freshwater ecologist for the Conservancy.
Extensive research conducted by the Conservancy and its partners at the University of Illinois has shown that wetlands, which help slow water and filter natural and man-made pollutants, effectively remove up to 60 percent of inflowing nitrates from underground tiles when they are strategically installed alongside agricultural fields.
In 2014, three new wetlands were constructed, and up to three additional wetlands will be installed this year. One of these wetlands, which is funded by the Coca-Cola Company, will be installed on city property.
“We are very excited about the new wetlands that are being installed around Lake Bloomington, as well as the development of effective nitrogen management practices” Lemke said. “These conservation practices will help to provide cleaner water for the residents of Bloomington, as well as protect wildlife that depends on quality habitat and water resources.
While this work is local to Illinois, it also aligns with the Conservancy’s global Water Funds program, which works with investors−primarily large businesses and government agencies−to establish funds for conserving key lands upstream that naturally filter water and reduce its speed across the land. Ultimately, the watershed conservation program in Bloomington has the potential to affect freshwater conservation further downstream.
“Our state is one of the highest contributors of nitrogen and phosphorus to the Gulf of Mexico,” Lemke explained. “That means the Bloomington Drinking Watersheds project doesn’t just benefit local residents; it has the potential to positively affect the hypoxia or “dead zones” in the Gulf of Mexico. ”
Updated July 7, 2015