PW: Where were you able to cut costs compared to the original consent decree?
Sherman: We took a two-pronged approach. While we increased the size of some facilities, we tried whenever possible to expand existing facilities rather than build new infrastructure. Then, to minimize as much as possible the size of any new or replacement pipes throughout the system, we looked for ways to keep runoff from entering the collection system. While the original long-term control plan included prescriptive requirements, the new plan has cutting-edge engineering strategies.
On the “gray infrastructure” side, the single largest opportunity for cost savings was achieved in our first amendment to the consent decree. We suggested replacing a 24-million-gallon interceptor with a 54-million-gallon deep tunnel that would capture and hold 1 billion gallons more raw sewage between the city's two treatment plants. Though it cost 70% more up-front, it enabled us to downsize or eliminate parts of the original plan, such as one of two new pumping stations; and keep stormwater from overwhelming the plants by holding it until they're ready to process it.
With a longer and larger-capacity tunnel, we were able to lower the total length of new pipe to be installed throughout the city, thus lowering associated right-of-way complications, and use smaller-diameter pipes to connect to the deep tunnel. We estimate the $129 million additional investment will reduce consent-decree compliance costs by $740 million and reduce the amount of raw sewage in surrounding waterways by more than 200 million gallons — a 36% increase over the original plan.
To us, this was the right approach: devising environmental solutions that better addressed overflow issues at the center of the consent decree while producing net savings over the original proposal.
PW: That tunnel redesign was a breakthrough for your planning. Who came up with that idea?
Sherman: Actually, the suggestion to make the “interplant connect” deeper and on a different alignment was evaluated years earlier, during the original consent decree's facility planning phase. But the impacts of the alignment weren't fully vetted and the flow and storage requirements of two tunnels that would connect to the main tunnel weren't fully modeled.
In 2008, shortly after I joined public works, Mayor Ballard's drive to eliminate cost overruns pushed us to revisit these issues. We decided to invest $5 million in consulting services, adding more flow meters and sensors throughout the watershed, and survey information to develop new flow models. As a result, the new design allows more flexibility in treating wastewater; flows can go to either plant whereas the original design would've had sewage on one side of the river going to the 300 mgd Belmont plant and the other side to the 300 mgd Southport facility. Both are being upgraded to allow secondary treatment of all sewage.
This is an example of a decision to invest in modeling up front, which is paying off in the long run by helping to identify savings. That enhanced model gave us better flow data to optimize the original design and to better define wet weather events and preferred solutions. For example, we learned that initial flow estimates were as much as 30% too high, and this became a critical factor in our revamped plans.
PW: How did you gain elected official and public support for the revamped plan?
Sherman: The revised plan satisfied Mayor Ballard's requirement that solutions remain sustainable 50 years from now. Changes were proposed to the city's technical advisory committees — engineers, scientists, and former regulators who helped critique our evaluations — through the process of updating the long-term control plan.
Changes were also discussed at many public meetings and meetings with industrial leaders and eventually published in the Federal Register.
PW: How much of the expected reduction in illegal-discharge volume can be attributed to natural control mechanisms rather than pipes and other “gray” infrastructure?
Sherman: Best management practices and other natural runoff-control solutions divert 1 to 3 million gallons from the combined sewer system.
We did a low-impact-development study that identified six additional opportunities throughout the city for enhanced green projects, such as building wetlands to reduce pollutant loads into the White River and reduce flooding into surrounding neighborhoods.
We also looked at how various projects could reduce the city's carbon footprint and minimize disruption to the environment and the public.
For example, a tunnel bore doesn't require as many entry points as an interceptor, so we lessened disruption to property owners and traffic patterns. The tunnel also allowed us to avoid a trichloroethene (TCE) plume discovered while the interceptor was being designed. The tunnel's depth lessened the impact to groundwater wells and dramatically reduced the right-of-way acquisition impacts associated with the original project.
PW: How receptive was the EPA to “green infrastructure” proposals? The agency has encouraged communities to use best-management practices, but now — under pressure from environmental groups that feel the agency's taking too long to clean up particularly polluted watersheds, like the Chesapeake Bay — doesn't seem convinced they do the job. Where does that leave communities that have implemented these methodologies in hopes of avoiding a consent decree?
Sherman: The city's won numerous awards for green infrastructure projects, which have performed better than expected. But evaluations aren't always as definitive as traditional engineering models.
That was one take-away for us. The mayor encouraged us to partner with regulators, industrial partners, and the public; and we did. But non-traditional control mechanisms are scientifically complex and the methodologies for estimating their impact on a long-term control plan are still under debate. In hindsight, we should've been more assertive, worked earlier to bring all stakeholders together and improve communication with EPA. By achieving more buy-in earlier for our methodology, the process could have moved at a quicker pace.
The city also pursued strategies to complement the mayor's strategy of supporting “sustainable” development. We'd done this before with great success. For example, in our Ohio Street abatement project, we used non-traditional measures to better manage stormwater while beautifying a significant transportation corridor into the city in an area that had no existing stormwater infrastructure. The project incorporates 2,650 square feet of pervious concrete sidewalk, 900 linear feet of pervious concrete curb and gutter, and 750 square feet of rain gardens. These retrofits manage runoff from approximately 60,000 square feet of impervious surface and will remove 1.35 million gallons of stormwater from the combined sewer system annually while creating a safer corridor for pedestrians walking along and across the street.
This is an example of the approach we took for green infrastructure in the consent decree discussions.
PW: How do public-private partnerships factor into any of this?
Sherman: What was unique to our strategy is the way we leveraged the private sector in terms of our organizational strategy.
When we engaged private sector industry experts, we formed an integrated team that was totally transparent in terms of the “private” versus “public” labels. We formed an integrated program team that allowed private sector staff to lead public sector employees, and visa versa, within the team structure.
We're truly an integrated team working toward a single goal.
PW: Indianapolis is the first city to modify a compliance plan to such a degree, reducing program costs from $3.8 billion to $3.1 billion for almost 20% in savings. What sets the city apart from those that have tried in the past?
MWH Global Program Development Director Mike Musgrave: The public-private partnerships that Mayor Ballard and Public Works Director Sherman created were critical to enabling public works to craft better environmental solutions that saved ratepayers money over the original plan.
The mayor is a member of the U.S. Conference of Mayors Water Council, which is engaged in discussions with EPA over the cost of regulatory compliance. He expanded the city's partnership to the conference and created an internal team that was fully integrated with the right experts from private industry.
PW: You've worked with several cities in similar situations. What best practices do you recommend for a community trying to avert or modify a consent decree?
Musgrave: Regulators have signaled they intend to continue using consent decrees to compel cities to comply with the Clean Water Act. We've seen a lot of enforcement activity in the last several years and I expect that to continue.
In working with other cities, one important “lesson learned” is to avoid entering into a consent decree with prescriptive requirements: numeric goals such as size of storage tunnels or treatment capacity. One city agreed to limit surcharges to sewers by 100%, an expansive requirement that provides limited environmental benefit.
Communities increasingly are approaching wet weather programs from an “adaptive management” approach, a process that involves continually monitoring key inputs and adapting an approach to meet a broader goal. In Indianapolis, we gathered better data around flow volume and adapted our approach to bring down the overall amount of overflows taking into account the new data. So be proactive about recommending solutions that meet broad goals, such as reducing the overall amount of overflows, rather than agreeing to numeric goals that have no real environmental significance.
This approach allows a community to better understand the watershed before developing and agreeing to a plan to address environmental issues. Indianapolis invested in a tenfold increase in flow meters, from 23 to more than 240, to get better data before refining strategy. A data-driven approach is more effective and less costly in the long run than more traditional approaches that may be narrower in focus.
Also, communities are more successful when they work with regulators to define performance metrics: ultimate control measures for number of overflows allowed each year. This tactic defines the ultimate environmental benefit and will allow you to develop the most cost-effective plan for meeting environmental goals.
Prepare for a potential consent decree by building teams that include experts from the engineering and legal communities to focus on financial responsibility and environmental stewardship. As Indianapolis' experience shows, those two goals don't have to conflict and can support one another.
Regularly evaluate the long-term control plan to identify and troubleshoot potential problems. With better information, you're in a much better position to meet the challenge and propose meaningful solutions.6 TIPS FOR A SUCCESSFUL DISCUSSION
How to increase the chances of negotiating a more financially favorable consent decree.Start the process early. Begin negotiations before you hear from regulators.Understand your wet-weather system's impact on the watershed.Assemble a team of engineering and legal experts to focus simultaneously on environmental and financial stewardship.Push for adaptive management strategies rather than prescriptive (i.e., numeric) requirements.Work with regulators to define performance metrics rather than having them imposed on you.Regularly evaluate your long-term control plan to identify and troubleshoot potential problems.