Illinois power plants have resorted to releasing massive amounts of extremely hot water into Illinois rivers and lakes, causing fish populations to rapidly decrease, according to the Illinois Department of Natural Resources.

Although Chicago power plants have not asked for any special variances to release coolant water the Chicago River system is still being affected.

With temperatures rising to 100 degrees Fahrenheit this summer, Illinois power plants have seen a steep increase in demand, causing them to reach near shutdown levels. Coal and nuclear plants have to draw in water to maintain a baseline of electricity within the plant, which forces the Illinois Environmental Protection Agency to grant facilities such as the Dresden plant in Morris and the Quad Cities plant in Cordova, special variances to release 100 F coolant water into surrounding lakes and rivers at a rate of 100 million gallons per day. Power plants need permits from the IEPA to stay in operation if their water supplies exceed 97 F.

According to a 2011 report by the Union of Concerned Scientists, dozens of power stations that rely on Great Lakes water for cooling kill an estimated 100 million fish annually.

According to the DNR, fish deaths are common in the summer, but this summer has seen a drastic increase because of elevated temperatures.

The water coming into the plants was already above normal temperatures, prompting the facilities to request variances from the IEPA.

According to the DNR, this has caused temperature-sensitive fish to migrate downstream toward unaffected parts of the waterway, such as the Chicago River, in order to avoid being scalded by the heated water.

If the variances had not been issued, the end result would mean blackouts for many Illinois consumers, according to Roger Callaway, IEPA environmental compliance manager.

“I can tell you that there were definitely alerts on the grid this year that justify the need for power,” Callaway said.

Because the plants typically used water that nears 90 F this summer, they faced the daunting task of cooling equipment vital for power production.

According to the Nuclear Regulatory Commission, whose job is to ensure that all nuclear plants are operating in accordance with safety procedures, plants must shut down if the internal temperature reaches 100 F—unless the facilities provide information stating that its safety limits have not been compromised.

IEPA communication manager Maggie Carlson said the variance permits are issued to ensure that there are no regulatory problems to plant operation, while considering the environmental concerns.

Although Chicago power plants were not issued permits, the discharge of heated water is still affecting the city’s river ecosystem, according to Jerry Mead-Lucero, a member of Pilsen Environmental Rights and Reform Organization, a group that monitors local environmental conditions.

According to Jared Policicchio, an attorney at the Environmental Law and Policy Center, the ELPC looks to use existing laws so state regulators will make sure permits being issued are in accordance with the law and dealing with the issue of thermal pollution.

“We need to move away from ways of genereting electricity that are heavily water-intensive,” Policicchio said. “Any form of generating electricity that is using steam to turn a turbine to create that electricity is going to require a lot of water to cool it down. Wind generation doesn’t require large amounts of water and neither does solar [energy].”