Indy's $3 Billion Plan

Clean Streams Program Aims to Enhance Waterways

by Don Talend

Like many Northern industrial cities, Indianapolis has a combined sewer overflow system that keeps combined stormwater and sewage off of city streets during major rainstorms but pollutes the city's river system at unacceptably levels in the process.

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More than many other cities, though, Indianapolis is making progress toward cleaning up its waterways by separating stormwater and sewage. That job is part of a sweeping environmental initiative in Marion County.

The $3 billion Clean Stream program consists of two main components: a Marion County Stormwater Master Plan and a Septic Conversion Program Master Plan.

The stormwater master plan is the result of a 20-year Raw Sewage Overflow Long-Term Control Plan that the city submitted to the Indiana Department of Environmental Management and the U.S. Environmental Protection Agency and formalized with the filing of a consent decree in U.S. District Court in October. The plan calls for several improvements to the city's combined sewer overflow, or CSO, system that will capture stormwater overflows for treatment at city treatment plants.

The septic conversion plan entails gradually replacing poorly performing septic systems with sewer systems in areas outside of the Indianapolis city limits but within Marion County. Indianapolis' Unigov system, which merged the governments of the city and Marion County in 1970, gives the city jurisdiction over the outlying septic systems.

Stormwater Master Plan

The driving force behind implementation of the $1.8 billion stormwater master plan is addressing sewage runoff and water quality issues in the neighborhoods of Marion County.

In response to numerous complaints from residents about sewage and water issues, Mayor Bart Peterson's administration developed a database for prioritizing improvement projects based on field studies.

Under a recently developed funding program for these projects, the city is gradually transforming the CSO system to a more sustainable alternative.

After the city developed a stormwater master plan in 1998, it did away with a flood control district tax that obtained maintenance and capital improvement funding from throughout Marion County. The tax, which proved inadequate for the region's stormwater infrastructure needs, was replaced in 2001 with a system that collects user fees from businesses on properties with runoff-generating hard surfaces, regardless of their tax status.

"As a result of that, we began to implement a more aggressive capital improvement program," says John Oakley, senior engineer with the Indianapolis Department of Public Works.

The additional funding available through the user fee-funded Stormwater Capital Improvement Program has allowed Oakley and the department to prioritize stormwater infrastructure improvements. One of the highest priorities has been enabling better management of CSOs at the city's two water treatment plants.

The Belmont plant is located along the White River to the southwest of downtown and currently treats about two-thirds of the city's sewage.

Bob Masbaum, administrator of environmental engineering for the DPW, says the Belmont plant and the Southport plant located farther to the southwest along the river have approximately the same capacity. "The Southport plant basically serves all the separate sewer areas on the outer edges of town, and the Belmont plant serves all of the combined areas in the center part of town," he adds. "During a large rain event, Belmont will start seeing an increase in flow pretty quickly, whereas the Southport plant tends to peak a lot more slowly."

The two plants are currently connected by a 5- to 6-ft-diameter diversion that is insufficient to ease the burden on the Belmont plant during major rain events. To correct this disparity in plant utilization, the DPW will have a 6.5-mi Belmont-Southport Interplant-or pipeline-constructed between the two plants that will use a 12-ft-diameter interplant and a pump station to move the water to the interplant.

The design phase of the $161.2 million project is scheduled for completion by February and construction should be completed by December 2012.

Another major project in the city's effort to reduce CSOs was the recently completed $19.2 million Pogues Run Sewage Overflow Reduction. The Pogues Run stream that runs through the city's downtown occasionally overflows near four schools located east of downtown.

These overflows are being mitigated through the rehabilitation of aging brick sewers and construction of a new tunnel to divert overflows to a downtown tunnel and away from the schools. The project is expected to cut Pogues Run overflows from about 22 to 38 during a year with average rainfall to about four.

The project took place in three phases. In phase one, a sewer collection box and connecting sewer were built under the Michigan Street ramp to north Interstate 65, also located east of downtown. This structure is now fed by three sewer pipes and diverts flow from the pipes to a tunnel and away from the schools.

The connection of the new sewer pipes to the tunnel constituted phase two. Phase three consisted of rehabilitation of aging brick sewers located northeast of the first two phases.

Chicago-based Walsh Construction Co. was involved in the first two phases of the project from December 2004 to spring 2006 as the contractor on the Pogues Run project. The company excavated for the overflow consolidation structure and partially constructed the structure.

Charles "Charlie" Gannon, project manager for Walsh, says the most difficult part of the project was installing the 3,200-ft-long, 6-ft-diameter connecting sewer.

"It was about a 12-ft-deep, open-cut excavation, but it was along a line of traffic, so it had to be shored using trench boxes," Gannon adds. "A pipe that size is quite heavy, so we were limited as far as the type of equipment that we had to use, and that equipment turned out to be almost too big for the area that we had to work in.

"At the same time, we were laying a dedicated storm drain alongside this sanitary pipe, so we had problems with laying a 72-in. pipe and a 24-in. pipe simultaneously, setting manholes with traffic going beside us, crossing streets and not contaminating things any worse than they were already contaminated."

Super Excavators of Menomonee Falls, Wis., used a tunnel-boring machine for the tunneling and also built part of the consolidation structure.

The first two phases of the project, in which Pogues Run was widened, yielded the added benefit of reducing the boundaries of a 100-year floodplain upon which the Cottage Home neighborhood is located. That means residents have been able to discontinue their flood insurance.

Septic Tank Elimination Program

When the Unigov system was implemented, the city inherited 30,000 homes that have septic systems. Among other initiatives, the city's Septic Conversion Program Master Plan addresses septic problems throughout suburban Marion County.

A boon to this effort has been the launch in 2006 of the $320 million Septic Tank Elimination Program, which provides a new way of funding the connection of these homes to a separate sewer system outside of the city infrastructure.

STEP will replace septic systems at 18,000 high-priority homes outside of the city limits over 20 years. Under STEP, the city pays for sewer construction in various neighborhoods and residents pay a contractor for a sewer connection. New sewer rates approved by the City-County Council will finance the new sewer construction, which is to replace septic systems at 4,800 homes from 2006-2008.

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