A billion dollar plan to keep raw sewage from seeping into Indianapolis rivers and streams will involve a network of underground tunnels.Officials said that raw sewage is often forced into rivers and streams, and the city's aging sewer system is sometimes unable to handle the excess water when it rains.Citizens Energy Group President Cary Lykins said engineers are mapping out a series of tunnels called the Deep Rock Connector to billions of gallons of waste water separated from clean water."It's an intolerable condition. You might see this in a third-world country, but not in a first-class city, Lykins said.In Southport, crews prepared the area where digging will begin in August for the first billion dollar storage tunnel, RTV6's Rafael Sanchez reported.The city is planning to place a total of five tunnels 250 feet underground.They will run near the Indiana State Fairgrounds to north along Harding Street to the south.Mayor Greg Ballard said the project will not impact traffic or neighborhoods."The environmental benefits will outweigh any inconvenience to the construction, Ballard said.Environmental advocates said the storage tunnels are not only a win for their cause, but every homeowner and business with a stake in the city's future."I think theres value in how we are perceived as a community and our quality of life, said Kevin Hardie with Friends of the White River.Officials said they expect the first phase of the construction to be completed in 2017 and the final phase to be completed in 2025.The total price tag of the construction could top $1.6 billion, but Ballard said the project will save taxpayers money in the long run.