The Fort Wayne City Council is moving ahead with plans for a 5-mile tunnel aimed at reducing the amount of raw sewage reaching the city's rivers during heavy rain. City Utilities official Matthew Wirtz told council members Tuesday that planners are trying to hold down costs for the estimated $150 million project. The Journal Gazette reports the council gave initial approval to spending $15 million on design work. The tunnel is expected to be 12 feet in diameter and at least 150 feet deep in the bedrock. Construction is projected to be finished between 2022 and 2025. Wirtz says the tunnel would help reduce sewage overflows from some 70 times a year to about four. A similar system with about 25 miles of tunnels is being built in Indianapolis.