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Civil Engineering Magazine THE MAGAZINE OF THE AMERICAN SOCIETY OF CIVIL ENGINEERS

Team Evaluates Water Distribution System in Flint

By Kevin Wilcox

In the aftermath of a highly publicized contamination event, the Michigan city is examining how best to upgrade and optimize its water lines.

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The City of Flint, Michigan, has hired a team led by the international design and consulting firm Arcadis to conduct an in-depth evaluation of its drinking water distribution system and to develop an optimization plan. Wikimedia Commons/BlueSkiesFalling

January 17, 2017—The City of Flint, Michigan, continues to move forward with improvements to its drinking water system after a contamination event made national headlines in 2014 and 2015. City leaders have hired a team led by the international design and consultancy firm Arcadis to conduct a comprehensive evaluation of the drinking water distribution system and develop an optimization plan.

The city has approximately 800 mi of water lines that will be included in the project, as well as about 30 million gal of storage in the form of two large reservoirs within the distribution system and a reservoir and elevated tank at the water treatment plant. The team will also examine a booster pumping station that serves an area of the city that experiences lower pressure at certain times.

The team that Arcadis has assembled includes as subconsultants Confluence Engineering Group LLC, of Seattle, a national expert in distribution system optimization, and Cornwell Engineering Group, of Newport News, Virginia, a firm that is coordinating the corrosion control efforts, according to Chris Hill, a vice president of Arcadis and the firm's water supply and treatment leader.

Corrosion control will be important because it was at the heart of the contamination incident that began in 2014. The city stopped purchasing water from the Detroit Water and Sewerage Department (DWSD) in April 2014 in favor of water pumped from the Flint River. However, the water supplied by the DWSD was being treated with orthophosphate, an additive that encourages the formation of a film layer on internal pipe surfaces that reduces the dissolution of lead.

What is more, the quality of the water in the Flint River is more variable than that of the water in Lake Huron, from which the DWSD had been obtaining its water. "The variability, combined with that lack of orthophosphate, is really what led to the destabilization event," Hill says.

Flint is now obtaining its water from the Great Lakes Water Authority, which was formed in late 2014 during the bankruptcy proceedings for the City of Detroit. The authority acquired many of the assets of the DWSD and assumed operations of the system in 2016. The water that the Great Lakes Water Authority provides to Flint is treated with orthophosphate, and the city is adding additional orthophosphate to this water.

One of the tasks of the team is determining the optimal level of orthophosphate to protect the pipes, Hill says. The members of the team agree that orthophosphate is the correct choice. "The system has seen enough changes," Hill explains. "In analyzing the current options available to them . . . orthophosphate addition is the most practical solution."

The three-phase project began in September with a stakeholder meeting that included Flint officials as well as representatives from the Michigan Department of Environmental Quality and the U.S. Environmental Protection Agency. The first phase, called a gap analysis, was concluded recently by Arcadis and its subconsultants. The team looked at the current state of the system and the extent to which it implements practices generally regarded by the industry as highly effective ("best practices") and then developed suggestions for addressing any shortcomings.

For the second phase of the project, which began recently, the team will assess the system's needs and develop a list of resources to close any gaps remaining from the first phase. In phase three, the team will develop and present a detailed plan for improvements that will include a prioritized list of water main replacement projects. In examining data on water main breaks and water loss, the team found that the aging system is typical of many systems in cities like Flint around the country. The replacement list will be built around three time windows. The first will cover the first 5 years, the second years 6 through 10, and the last years 10 through 20. The city has received both state and federal funds to address the issues with the system.

Hill says that the biggest challenge for the team, however, is outside the technical arena. The chemistry and pipe replacement elements are straightforward and based on practices deemed to be the best in the industry. However, public trust in the system was damaged by the contamination event and its aftermath.

"I think the biggest challenge that the project and the city face is restoring trust in the water system with the public," Hill says. The team has hired Detroit-based McConnell Communications, Inc., as a subconsultant to develop a strategy for allaying public concerns.

The team began with a large public meeting at which it introduced the project and listened to residents' concerns. That has been followed by other public meetings at which the team has outlined work that is under way and described the steps that are to follow. Hill says the public is appreciative of their updates and has greeted the project with an open mind.

"It has not been easy. They have been through a lot," Hill notes. "But they are happy that Arcadis is there and we are talking openly with them. We are committed to helping the city establish a relationship with its residents with the focus on educational outreach and engagement."

In addition to the meetings, the team is developing a website to serve as a key central resource for the public. It is also exploring social media, email campaigns, and newsletters as other communications channels.

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