Marshfield Utilities Shares Information on Water Main Breaks
Submitted to OnFocus – One of the inevitable things about winter are water main breaks. Each year is a little different; breaks can be spread out evenly throughout a period of time or can come back to back, we can have minimal numbers or like in 2014 we can have a record breaking year, they can be easy to find and fix or they can literally and figuratively take quite a bit of digging. The value of safe and reliable water is undeniable and it warrants the efforts the water department puts into our system every day.
Between main breaks, hydrant leaks, and valve leaks the most prevalent by far are main breaks. In an average year the Marshfield Utilities (MU) crew will repair 35 main breaks, with the high record year in 2013/14 reaching 74 and the low record year in 1981/82 only reaching 5. In comparison to main breaks, MU replaces about 5 hydrants and 10 valves a year due to leaks. With the number of main breaks and the large amount of pavement replacement needed, main breaks are the most costly.
Main breaks are tracked from July 1st through June 30th each year. For this current year we are currently up to 30, which puts us on pace to have roughly 50 total. This is due in large part to the two week span where we had extreme below zero temperatures which pushed the frost depth down 2.5 feet (from 1.5 feet to 4 feet) in 10 days. The faster the frost pushes down, the more stress it puts on the pipes which results in main breaks. The same can happen in the spring based on how quickly the frost melts. When the frost melts the pressure is reduced and if this happens rapidly main breaks are caused in the same fashion. In a perfect world the frost would go down and be let off in a very slow manner.
Fixing a main break starts with MU getting notified of a potential problem by someone such as a customer, dispatch, or the street department. Someone from the water crew will go to verify an actual problem. While this may seem like a waste of time, there are times it turns out to be snow melt runoff, a sump pump from a customer’s basement, or a customer’s outside faucet that was turned on and left running. If we concur that it is a main break or leak of some sort on our side, we call Digger’s Hotline to get the process started and then organize a crew for the work. Organizing the crew can take some coordination if after normal working hours and the after-hours answering service helps facilitate these calls. While a crew is being assembled, the initial crew member tries to notify affected customers and locate the necessary valves to isolate the leak when the time comes to shut the water off. When a second crew member comes in, they work to pinpoint the leak via a correlator to know exactly where to dig and also make sure the valves are all thawed out and vacuumed out to be prepared to shut the water off. MU doesn’t turn the water off right away if it is not creating a hazard to minimize the amount of time a customer is without water. After Digger’s Hotline locates all of the underground activities and the leak is located, the crew shuts the water off and starts breaking out the pavement (asphalt, concrete, sometimes both) and excavate down to the water main. Once the excavation has reached down to the water main the crew then must clean the pipe off of all debris (soil, mud, rocks, frozen particles) and put a water main sleeve around the affected area to stop the leak. They then slowly turn the water on to fill and flush the pipe. They will take a safe water sample and start back filling the excavation. Sometime later, most likely in the summer, MU’s contractor will come back to the location and repair the street to previous existing conditions.
MU does take proactive measures with regard to the health of the system. Approximately $800,000 to $1,000,000 of water main is replaced every year. The specific sections replaced is coordinated with areas the city has street projects which minimizes cost and customer inconvenience. Replacing water mains helps to minimize main breaks, but it also allows for increased pipe size in areas that need it. As the city grows, water is needed to go farther and farther from the sources and the most efficient way to move water is through larger pipes. In water replacement projects, MU is able to install temporary water so a customer is never really without water with the exception of a few minutes during the switch over from the old water main to the temporary service and then back to the new water main once it is ready. Those outages are planned and then can be worked around a customer’s needs versus an unplanned outage, as well as more efficient working conditions such as the time it takes to dig down during the summer in comparison to jackhammering through frost to reach a main break.
According to GIS records the oldest sections of water main were installed in 1926. While it might seem like a lot to spend annually, MU remains committed to steadily working to replace these older and less reliable sections and hopefully reducing the inconvenient and unplanned main breaks.
– Melissa Barnes & John Richmond, Marshfield Utilities
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