The U.S. Fish and Wildlife Service, in cooperation with the City of Alton and the Illinois Department of Natural Resources, invites the public to review and comment on a draft Environmental Assessment (EA) for the construction of a marina breakwater extension on the Mississippi River in Alton, Ill.
The draft EA evaluates three action alternatives, including the proposed alternative. All three action alternatives would extend an existing breakwater to the Illinois shore to prevent silt from depositing in front of the existing boat ramp and launching area. A “No-Action” alternative is also evaluated in the document. The project will use Boating Infrastructure Grant Program funds made available by the Federal Aid in Sport Fish Restoration Act. These funds come from federal excise taxes on fishing tackle and motorboat fuels.
The southern boundary of the Alton marina is formed by a 1,300-foot-long rubble mound breakwater. This breakwater, known as the “Trail Dike,” was constructed by the U.S. Army Corps of Engineers as part of its program to reconstruct Lock and Dam 26. The Trail Dike is responsible for the creation of a large silt that has formed downstream of the marina.
The silt has increased to the point where some river flow is running upstream between the and the Illinois shore. This “backflow” is entering the marina through a gap in an existing breakwater and, as velocity slackens, silt deposits in front of the boat ramp and as far into the marina as the fuel dock.
The proposed alternative would address this problem by extending the existing breakwater to the shore to provide a closure and prevent silt from entering the marina. The three action alternatives comprise three different extension configurations and construction methods that would each provide the necessary closure. The proposed alternative is a vertical sheet pile wall that would maximize maneuvering space in front of the boat ramp and be constructed entirely on city property.
The EA was prepared in compliance with the National Environmental Policy Act, which applies to the actions of all federal agencies. This project is proposed by the City of Alton and the Illinois Department of Natural Resources for funding through the Boating Infrastructure Grant Program (Federal Aid in Sport Fish Restoration Act), administered by the U.S. Fish and Wildlife Service.
The draft EA is available on the U.S. Fish and Wildlife Service Web site at
