Hamilton County sits immediately north of the Ohio River, at the southwest corner of Ohio, near the lowest point in the state. Cincin-nati is its major metropolis. Aging infrastructure has led to a continuing problem with CSOs and SSOs, but the Metropolitan Sewer District of Greater Cincinnati is on track to eliminate them by 2038.

The key to the plan is a broad collaboration of municipal and political leaders, and an informed citizenry, all concerned with protecting environmental quality. And a critical part of the solution is a wide variety of green infrastructure for stormwater control.

“The Earth Day generation has now reached positions of power and influence, so there was an ‘underground army’ ready to strike when given the chance,” observes Karen Ball, MSD compliance coordinator for the county. The first Earth Day was on April 22, 1969, and it strongly influenced a generation bent on social and environmental change.

MSD’s coalition includes leaders from 49 jurisdictions, including the Ohio DOT and the Transportation and Planning Agencies of Cincinnati and Hamilton County. The district also has the support of the local chapter of the Sierra Club. It’s this powerful coalition of people and perspectives that allows MSD to move forward with a host of innovative solu-tions to its CSO and SSO dilemma.

Tough geology

In addition to the aging infrastructure, MSD’s task is made more difficult by the sheer magnitude of the system (3,100 miles of sanitary and combined sewers), the large fraction of impervious surfaces in its jurisdiction (38 percent), less-than-favorable soil conditions, and a shrinking tax base due to an exodus of residents to adjoining counties.

MSD’s service area lies in what is best described as a topographical funnel: Runoff from adjacent areas is channeled in by natural drainage slopes. Further, the area contains a large percentage of impervious surfaces. The district’s GIS records a total of 96,317 acres of land, 37,053 of which are impervious.

The soil is less than ideal. Some 60 to 70 percent of it falls into hydrological soil groups C and D. The “good” soils (A and B) lie mainly along the floodways of major water courses, such as Mill Creek and the Great and Little Miami rivers. And 40 percent of this soil area has high water tables averaging 10 to 30 feet. With an average of 40 inches of rainfall each year, it’s not surprising to see frequent CSOs and SSOs.

Before joining MSD, Ball worked for three years as a legislative aide for the City of Cincinnati, and six years as an aide to the Hamilton County commissioners. At that time there were few environmentally sensitive elected officials. Most policy makers were driven by a “sprawl mentality,” pushing development for its own sake.

“Smart growth principles we promoted were not popular in the mainstream developers’ minds,” Ball recalls. “Infrastructure conditions in the city core and first-ring suburbs were causing problems. Oddly enough, the CSOs didn’t seem to matter.

“The tables turned in 2006 when Hamilton County board commissioner Todd Portune, previously the lone voice for the environment, was joined by others who shared his vision,” Ball says. “The majority on the boards shifted at both the county and state levels and opened the door to new conversations about how to solve the problems.”

Still, Ball’s coordination effort is a formidable task. With 49 jurisdictions to juggle, and a need for consistent strategy throughout the system, communication is key. In addition, there are three regulatory agencies to contend with, each with its own priorities: the U.S. and Ohio EPAs, and the Ohio River Valley Water Sanitation Commission.

Consent decree

Under the Clean Water Act of 1977, cities are required to reduce (and in some cases eliminate) the release of untreated wastewater through CSOs and SSOs. Because this remediation can be a long-term, expensive project, MSD began negotiating in 1997 with the EPA, the U.S. Department of Justice and the State of Ohio. The goal was a response plan that would be recognized and supported by the government, and affordable to local ratepayers.

The first result was an Interim Partial Consent Decree, accepted by all parties in February 2002. Under this plan, MSD must:

• Eliminate the 17 most active SSOs by the end of 2007.

• Develop a plan to resolve the remaining SSOs by 2022.

• Develop a computer-based model of the sewer system to better determine capacity limits and future planning.

• Build a temporary treatment plant to reduce the discharge from SSO 700 (the system’s largest) while implementing a permanent solution.

This was followed, one year later, by the Global Consent Decree, a draft of which is still under review. If it is approved, MSD would:

• Complete 23 pre-identified projects to reduce CSOs.

• Update and implement its Long-Term Control Plan (LTCP) to include comprehensive water quality testing, computer modeling, cost/ benefit study of options for correcting CSOs, and public review.

• Implement enhanced CSO control, response and public ­notification.

• Invest $5.3 million in local environmental enhancement projects.

• Pay $1.2 million in fines for past SSOs and CSOs.

The three regulatory agencies were not entirely satisfied with some aspects of this plan, primarily the 9 billion gallons of untreated runoff still impinging on Lower Mill Creek. ­This necessitated MSD’s revised Wet Weather Improvement Program (WWIP), submitted in September 2008. Changes include a budget increase from $1.99 billion to $3.29 billion, enhanced high-rate treatment technology combined with increased storage capacity, and elimination of proposed in-system disinfection and screening from the plan (because effective green infrastructure made these measures unnecessary).

In addition, MSD will enact a Water-In-Basement (WIB) Response Program, the goal of which is to eliminate basement backups. This program includes:

• A new process to help MSD respond quickly to customer calls.

• One-on-one customer service for people experiencing WIB issues.

• Cleanup service to help remove standing water and debris from affected homes, including disinfection and deodorizing.

• Reimbursement for property damage (subject to legal conditions).

• Installation of WIB preventive measures such as check valves and isolation pumps (short term), and increased system capacity (long term).

Potential costs

The Global Consent Decree, if approved, represents a massive and costly project. And there are still some major unresolved issues. Depending on the efficacy of green infrastructure tactics, it may yet be necessary to build “The Tunnel,” a 25-foot-diameter conveyance structure 6 miles long, up to 150 feet deep, to channel combined flow to the Mill Creek treatment plant.

Part of the original Corps of Engineers plan, the tunnel was shelved in 2004 because of funding shortfalls. Total cost to meet the Consent Decree would be capped at $3.2 billion, spread over 30 years (if the tunnel is needed). MSD still sees the tunnel as a last resort and hopes to avoid it through green infrastructure and other measures.

Service rate increases will be necessary. For 2008, the increase is projected at 12 percent, raising the average quarterly sewer bill by about $23. More increases are expected in the future. MSD knows some customers are financially vulnerable. All rate increases must be approved by the Board of Commissioners.

Industrial and commercial customers (including apartments), comprise the bulk of MSD’s system load. These customers tally about 15 percent of the service area, and 24 percent of the impervious surface. The properties provide dramatic opportunities for storm-water control that can offset potential rate increases.

Potential solutions

The scope of MSD’s project is characterized in its 86-page Green Infrastructure Program. Here, the district details how it intends to win the war. Although the task may seem daunting, the coalition of green forces enables solutions.

“I threw myself in front of the stormwater bus, and the grass roots folks were there to pick me up,” Ball notes. At first pleasantly surprised by the groundswell of support, she quickly learned to leverage that support into real progress. The engineers believe they can reach 85 percent CSO and SSO control, or better, in some cases simply by using green storage solutions.

Solutions include rain gardens, vegetated swales, pervious and porous pavement, green roofs, sedimentation catchments, recharge wells and gray-water systems for irrigation. The National Resources Defense Council released its “Rooftops to Rivers” report in May of 2006, validating these solutions with case studies, and encouraging their adoption nationwide.

The grassroots army has been mobilized through programs like the Greenacres Foundation Project for the Little Miami, a National Scenic River. This community outreach effort allows volunteers to monitor and sample local rivers and streams, testing for pH, conductivity, nutrients, sediment and bacteria. The project is in its fifth year, and MSD hopes to use the results to document the efficacy of green infrastructure.

One noteworthy project is the 1600 Gest St. project, part of a countywide commitment to reducing runoff from public structures. This MSD-owned property includes 11 acres of buildings and other impervious surfaces. Early estimates place the cost of study, design and construction at $500,000. Green technology installed here would significantly reduce outflow and, perhaps more important, serve as an example for others and provide educational exposure to the public.

Another innovative project is the U.S. EPA-sponsored “reverse auction” program for rain barrels and gardens in the Shepherd Creek watershed. Homeowners are allowed to place open bids on the materials to build rainwater retention systems on their properties, and MSD provides the funding and coordination with local contractors. This popular program is making an impact on runoff and infiltration and will be expanded pending results of monitoring and analysis.

Outlook for the future

MSD’s immediate priority is to get the green infrastructure up and running. To make this all happen, Ball oversees the capital budgets, reviews capital expenditures before they go to the commissioners for approval, coordinates MSD work with NPDES Phase 2, manages development of rules and regulations (and works to get them passed), and negotiates with the Sierra Club for continued support.

“Since I took this job, my title hasn’t changed, but the number of things to do has increased,” Ball says. “Ultimately, I have to work hard to get all this to happen across the 44 jurisdictions participating in the Hamilton County Stormwater District.” In some of these jurisdictions, zoning laws limit the adoption of green technologies. Changes are needed to permit these applications as required.

Current work focuses on increasing the capacity of 12 wastewater treatment plants, improving conveyance, and reducing treatment loads with green infrastructure. One new treatment plant is planned for the northern part of the county, where gravity service will provide an effective long-term solution. This will eliminate two pump stations, the antiquated Wade Mill treatment plant, and a 30-year-old large force main that feeds the Mill Creek treatment plant.

Still, at the end, it all comes down to basic and established ideas. “I believe restoration of the ecosystem on private properties is key to keeping stormwater out of the system,” Ball says. “There will be monumental costs, and it will take a lot of collaboration, government included, to get the job done. Ultimately, the solution will be a mix of green and gray.”

The “green army” has its marching orders, and the battle has been joined.