Watermain repair job instills lesson learned
The City of Dayton has decided to reconfigure and reroute the piping.
Congested underground infrastructure played a role in the large water main break on Aug. 3 that left thousands of Dayton-area customers without pressure or service and led to a boil advisory, city offifficials said.
After a large main ruptured, the water that gushed out caused erosion that led to another pipe’s failure, affecting service to far more customers than the initial break, officials said.
The city has decided to reconfigure and reroute the piping that failed to create space between the lines to reduce the likelihood that one break will lead to others, officials said.
“This is an example of lessons learned and howcan we improve this situation with an investment so that we are lowering risk in the future,” City Manager Shelley Dickstein said.
Despite three major water ser
vice disruptions in less than 18 months, the city says its water system’s performance and reliability are strong and improving, which is evidenced by the overall declining rate of water line breaks and leaks.
Also, the city recently issued a request for proposals to find a company to assess and repair its large water valves with the goal of improving its distribution system.
Aug. 3 incident
Dayton has not completed its reviewof theAug. 3 water main break near the Ottawa Water Treatment Plant that flooded the streets and impacted about 27,000 customers mainly in downtown and eastern and southeastern Dayton, officials said.
City officials, however, say the break happened in an area where three separate water distribution pipes operated in close proximity to each other, though they were buried at different depths.
A 48-inch pipe installed in 1951 that serves the city’s lowpressure area broke for still undetermined reasons, officials said. This break caused erosion that led to the failure of a 30-inch pipe installed in 1893 that serves the high-pressure system.
Severe erosion also damaged the surface of a 36-inch pipe, which was installed in 1926, that serves the high- pressure area, officials said.
The initial break impacted service to about 17,000 customers in the low pressure area. The second break affected about 10,000 customers in the high-pressure area.
After events like this large disruption, city staff and team leaders in the relevant departments perform a debrief to evaluate what happened and howthe city responded, Dickstein said.
The city takes a close look at its performance, identifies areas for improvement and explores potential investments or projects that could prevent similar events in the future, Dickstein said.
Next steps
Instead of just repairing the broken or damaged pipes, the city has decided to realign the 30-inch and the 48-inch lines to reduce the cluster of underground
water infrastructure in the area, Dickstein said.
Pipes will be routed across Keowee Street at a location north of the break point.
The extra space, they said, should help prevent one water line break from causing additional line failures.
“If we are going to make this repair, let’s do it right,” said Michael Powell, Dayton’s director of the water department.
The city says it is evaluating whether other similar clusters of water pipes exist around the city.
The city also recently
issued a request for proposals seeking a vendor to assess the condition of its large water valves and make repairs.
The waterdepartment has 21,517 system valves, and 667 are 16 inches or larger, which are considered transmission mains, according to city documents.
The city said large valves are critical to the “resilience” of its water distribution system and it wants a detailed report that spells out a rehabilitation plan, including the scope of the projects and cost estimates.
The vendor will complete
repairs to valves the city’s water department deems “economically feasible” priorities, city documents state.
Officials said this request is unrelated to the recent break, but it will help prioritize capital improvement projects and improve the system.
Breaks and leaks
The city has about 100 water line breaks and leaks each year, though most are minor and have minimal impact on service, Powell said.
The Aug. 3 incident, however, was the third major
water disruption since early 2019.
In February 2019, the city’swater distribution systemsuffered a massive and widespread outage after a largemain in the river burst. Months later, theMemorial Day tornadoes knocked out power to parts of the city’s water system and led to another large water outage.
Each of the three major disruptions were different, and Powell said it is important tokeepinmindthatsome things are out of the city’s control, like the record number of tornadoes that tore through the area onMemorial Day 2019.
The city also claims that a contractor working on a bridge replacement project was responsible for causing the first outage.
The city constantly evaluates its system, Powell said, and uses software and other tools to analyze data to figure out what repair and replacement projects are most urgent.
The goal is to evaluate the likelihoodandconsequences of infrastructure failures, he said, and special attention is given to critical infrastructure around schools, hospitals, police stations, recreation centers and other sites that are important during emergencies.
Main break history is one consideration in the prioritization process, and soil condition is another. The age of the pipes and thematerials they are made of are other parts of the equation.
More than half (55%) of Dayton’s water pipes were constructed before the 1950s, and about 5% were constructed in the 1800s. Almost two- thirds of the pipes are cast iron, and rest are mostly made of ductile and concrete.
Powell said he’s not overly concerned about any type of piping in the 800-mile network thatmakesupthe city’s system, despite the advanced age of some of the lines. He said most pipes were well made, have long life spans and remain in good shape.
Powell saidDayton’s water system has a much better performance record than other systems across the country.
Better rate
The American Water Works Association’s target range forwater distribution systems is 22.9 to 78.7 breaks per 100 miles of water piping, Powell said.
Lastyear, Daytonhad20.7 breaks per 100 miles of piping, according to city data. Between 2015 and 2018, the rate was between 22.4 to 60.4.
“We’re not just sayingwe have awell-run utility — but according to AWWA benchmarks, they say we have an excellent-run utility,” Powell said.
Dayton officials said they cannot predictwhere breaks will happen, but that the declining rate of breaks and leaks shows their plan to upgrade the system isworking. The plan dates back to 2012.
“There is a difference between proactive and clairvoyant,” said Joe Parlette, Dayton’s deputy city manager.
Dayton is investing about $30million each year in new waterdistribution and sewer pipes, Dickstein said.
Between 2013 and 2019, the water department awarded 173 water, sanitary sewerandstormsystemprojects valued at a combined $200 million, Dickstein said.
Also, Dayton is in amuch better shape than other municipalities because its water, wastewater andstorm water systems are separate, Dickstein said.
Dayton also is researching sensor-based technology that can help detect leaks early before they become breaks.