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Eagan: Water treatment proposal causes controversyPosted: 12/12/03 by Erin Johnson The Eagan City Council is considering a proposal to treat Fish Lake and Blackhawk Lake with doses of alum, a chemical that removes phosphorous from water. But some residents are concerned about the effects of treating chemicals with more chemicals. Phosphorous, found in many lawn fertilizers, contributes to algae and plant growth in bodies of water, said Eagan Water Resources Coordinator Eric Macbeth. The objective of alum treatment is to reduce phosphorous levels and improve those water bodies, he said. ìA lot of our parks have beautiful lakes and wetlands that provide an amenity to the community,î he said. But in the past 20 years, the city has experienced population growth of more than 200 percent, he said, which has put an additional burden on watersheds. ìWhat we are facing today is an urbanized area that has had a lot of runoff into these lakes and ponds and wetlands, and our challenge is how do we maintain and try to improve those water bodies,î he said. The state has already taken steps to reduce the amount of phosphorous that enters water through rain runoff. As of January 2004, the use of residential fertilizer containing phosphorous will be prohibited in metro area cities. But cities still have to figure out how to deal with phosphorous that does make it into the water. Eagan conducted a pilot program from 1998 to 2001 that treated Fish and Blackhawk lakes, as well as a wetland area called JP47, with doses of alum. But some say treating phosphorous with alum is like ringing a doorbell with a canon. Some residents who live near the proposed treatment area appeared at a council work session Monday to oppose the project. Resident Patrick McCarthy, who owns land adjacent to the lakes in central Eagan, said he is against the project. During the pilot program, JP47 was used as a catch basin for the alum and phosphorous, causing it to accumulate sludge, which emitted a ìstinkyî odor, he said. Linda Haugen, who lives near the JP47, agreed, saying it smells ìlike a sewage pond.î Macbeth said that a new catch basin with more water volume would be created for the chemicals if the project is approved, which would relieve JP47 as a collector. The smell, he said, occurs when the sludge gets close to the surface and mixes with air, causing it to decay. Because it was a short-term program that was discontinued, sludge in JP47 was bound to accumulate, he said, but it was not expected to accumulate such a large amount. The new catch basin, which will be operating on an ongoing basis, should not experience that problem, he said. ìWeíre not going to tell people that thereís not going to be any odors, but we do know that we will have a lot more water volume above the material,î he said. ìWe donít expect to have any odors associated with this setup when its running.î Residents also had concerns over the environmental impact of the alum treatments. Hogan said the alum dosing ìkilledî JP47. The fish and turtles are dead, she said, and the blue heron and egrets that used to flock there are gone. ìAlum is one solution, but itís not the only solution,î Haugen said. ìApple Valley has a rain garden system ... which is a natural system for cleaning up rainwater. They are not injecting anything into the environment that becomes poisonous sludge.î Eagan also employs a rainwater garden, located in Cedar Pond Park, but that system would not work on an area the size of Fish Lake and Blackhawk Lake, Macbeth said. ìIím trying to impress upon people that a 2,500 acre area drains through this pipe,î he said. ì(Rainwater gardens) have limited value on that scale.î Alum works, he said, and while it is not exactly good for the environment, ìitís not altogether environmentally harsh,î he said. ìWe would be very supportive of a more environmentally-friendly option,î he said. ìBut thereís no perfect solution here.î The council is expected to make a decision on the alum treatment proposal early next year. Erin Johnson is at eagan.thisweek@ecm-inc.com. -- Check out this week's newspaper for more about your community. © Thisweek Newspapers |
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