Going back nearly 200 years to the 1820s, MGP sites in this country used coal and oil to produce gas as fuel for lighting, heating and cooking. Over the years, as natural gas became more readily available, this process was phased out, and MGP sites were no longer operated by the 1950s. However, their environmental remnants remained.
Over the last 20 years, Interstate Power and Light Company (IPL) and Wisconsin Power and Light Company (WPL) have been cleaning up old MGP sites across Iowa, Minnesota and Wisconsin, restoring the land for public use wherever possible. Through previous or present ownership, IPL is responsible for 32 former sites in Iowa, six sites in Minnesota and two sites outside of our service territory. WPL has responsibility for 14 sites in Wisconsin.
Each MGP site goes through a multi-year process to investigate, clean-up, and restore the land. Alliant Energy focuses clean-up efforts on the sites with the highest risk with only two major clean ups remaining. The majority of sites are now in the long-term monitoring phase to document that residual contaminant concentrations are stable or declining. To assure that risk associated with residual impacts is properly managed for future land uses, the company follows state-based administrative regulatory processes to document site status.
Once all requirements are met, Environmental Regulatory agencies issue "No Further Action" or "Regulatory Closure" letters meaning the site no longer poses a threat to human health or the environment. The site is then released from further remediation or monitoring requirements.
From industry to green space
Two recent examples show how we converted old MGP sites to usable green space for the communities to enjoy.
WPL throws Fond du Lac dog owners a bone
The Fond du Lac MGP operated from 1918 to 1930 and WPL began site investigation activities in the early nineties. In 1999, WPL began using a WDNR-approved system for pumping and treating contaminated groundwater. Eventually a layer of clean topsoil was added to 
the site to allow grass to grow while the groundwater pumping was underway.
Beginning in 2007, approximately 2,000 hybrid poplar and willow trees were planted in the western portion of the property to treat the contaminated groundwater, eliminating the need to pump water to the surface to treat it. The trees absorb groundwater contamination without being affected and provide a natural cost-effective method of cleaning up the site.
In 2008, WPL worked with the city of Fond du Lac to open a dog park at the site. The exercise area is on the eastern portion of the site where the east and west branches of the Fond du Lac River come together. The entire area is fenced off so dogs can run and play off leash.
The popularity of the dog park has grown over the last couple years. A group of volunteers now keeps the park mowed, clean and also updates a communication sign that was donated to the park. The city points to the dog park as a great example of the success that can happen when the city, the community and businesses work together.
A place to enjoy the outdoors in Austin
In Austin, Minnesota, IPL recently converted the former Austin Gas Manufacturing Company site, almost five acres, into green space for the entire community to enjoy.
The plant served the city of Austin from 1905 to 1935. IPL bought the Austin Gas Manufacturing Company in 1924. While the site had been used since 1935 by a variety of retail and commercial users, below ground contamination from things such as coal tars, oils and other chemicals remained. In 2002, IPL began the multi-year process of cleaning up the site in order for it to be transformed into green space.
More than 1,100 tons of concrete, asphalt, and metal scrap removed from the site were recycled during the project. Also, IPL excavated and treated more than 31,000 tons of soil with a mobile thermal decontamination unit. Treated soils were then placed back in the excavation and covered with topsoil. In 2009, the area was then planted with native trees and prairie species and access was added to the existing bike path. Now cleaned up, the site also serves as a trailhead, connecting to the nearby Cedar River trail, for public recreation.
