The Oakley Dam Project was part of a larger trend in American politics to promote industry in the wake of the Cold War through the construction of infrastructure around the country, including dams. Known as the “Big Dam Era,” the Oakley Project was one of these many efforts by the U.S. Army Corps of Engineers to manage American waterways. The Oakley Dam, located on the Sangamon River in Piatt County, was intended to assist with Decatur’s water supply, control flooding, as well as offering a new recreational area in the form of a reservoir. Originally the project would create an eight-mile-long reservoir, but changes made to the proposal in 1966 would result in a twenty-four-mile-long reservoir, and subsequently, the flooding of over 1,000 acres of Allerton Park.
The estate at Allerton Park was built in 1900 by Robert Henry Allerton on land that his father, Samuel, had bought throughout his life. Robert was an avid art lover and collected many pieces during his travels. The park you see today if full of these treasures. With Robert’s death in 1964, the park was gifted to the University of Illinois for the continued enjoyment of the community. With over 1,500 acres of woodland and prairie, Allerton Park includes some of the last remaining old growth bottomland forests in the state of Illinois. These lowland and upland forests would have been flooded if the dam completed construction.
When visiting Allerton Park in 1967 Bruce and Patricia Hannon heard about this news and immediately sprang into action. They organized a group of community members, called themselves the Committee on Allerton Park (COAP), and began what would be a decades long fight to stop the Oakley Dam.
Initially, the group circulated a petition that quickly gathered over 20,000 signatures from community members. COAP took this petition to the Illinois state legislature, who asked the Army Corps of Engineers to revisit their plans for the dam and justify its construction. Hannon quickly brought on John Paxton and John Marlin to assist, and they began an intense letter writing campaign to local and state representatives. A second petition circulated in 1968 totaled over 80,000 signatures.
But COAP did not stop there. John Marlin published Battle for the Sangamon River in 1970. This text used expert scientific research to argue for the preservation of Allerton Park and became the definitive text for dam opposition groups across the country. They found that the Army Corps had vastly overestimated the Sangamon River’s floodplain and vastly underestimated the costs to build it.
For the next ten years, the Committee on Allerton Park leaders, including Hannon, Marlin, and Paxton, would travel to Washington DC to argue against the dam in front of congressional appropriations hearings. These efforts coincided with growing public interest across the country in environmental preservation and conservation. The National Environmental Policy Act was passed in 1969, which requires all branches of the government to consider environmental impacts of any federal action. The following year marks the very first Earth Day celebrations, which included demonstrations across the United States and signal a powerful public stance on environmental issues.
The Oakley Dam project was finally killed in 1975. Political pressure and the activism of local communities along the Sangamon River was fundamental to this success and spurred countless other similar movements. The Committee on Allerton Park continued their work bringing attention to the waterways of Illinois and the Midwest for years. They eventually shifted to Prairie Rivers Network and persist today in their fight to protect the rivers of Illinois.