FORT WAYNE, Ind. (AP): Officials in Fort Wayne are working on plans for a seven-mile tunnel aimed at reducing the amount of raw sewage reaching the city's rivers during heavy rains. 

Preliminary plans for the project call for the tunnel to be drilled about 150 feet below ground. Once built, the tunnel would hold water from the city's combined storm and sanitary sewers after storms until it can be treated.

A city engineer says the sewer system now has about 70 times a year when raw sewage is discharged into the rivers. He says the tunnel project would help reduce that to about four times a year.

The tunnel is estimated to cost about $150 million, with work not expected to start until at least 2017.