Archive, Editorial, Infrastructure

Main Break on Constitution Avenue


I had just gone to bed on Friday night, October 15 when I got the call about a main break. A large 24 inch main on Constitution Avenue NW had burst right at the intersection at 10th Street. I was on the scene in about 30 minutes, and remembered that this intersection is right in front of the Smithsonian’s Natural History Museum on one side, and the US Department of Justice and Internal Revenue Service on the other. Constitution is one of the main arteries through the city.

All the challenges that come with water main breaks were evident. First, it was not easy getting the water off to the particular line, without also turning off water service to some very prominent buildings. Getting the right combination of valves turned combined with adequately draining the water that is already in the pipe, is a trial and error process that relies on the maps our inspectors have in their trucks outlining every pipe and valve. In the city, we have more than 36,000 valves.

Next, we had to get the underground utilities marked. This includes a major gas line, electrical and phone lines, sewer and stormwater, and other lines associated with electrical or communication grids. Utility marking is done by a private company – which had us all waiting for nearly 8 hours until they finally did the marking job. We can and won’t dig until we know where the utilities are located.

Third, we had to mobilize a series of crews to do the work. We needed inspectors to oversee teh work and review the latest plans, valve crews to regulate the flow of water, water crews to dig the hole and then repair the pipe, sewer crews to clean the storm drains to get the water to drain, and public information and the general manager’s office to help coordinate the effort, interact with other agencies, and keep the public informed. We had to mobilize a backhoe, trucks, lighting, safety material — all on a Friday evening after midnight.

Third, we had to get the road open and the pipe break localized and then fixed, Although we do our best to pinpoint the problem before opening the street, we are often unsure until the excavation begins. In this case, the broken pipe was broken about 10 feet to the South and West of what were originally expected. The excavation has to be done carefully – so we don’t damage pipe that is still functioning, or damage any of the other systems under the street.

Fourth, we have to acquire and shape components to repair the pipe. The sewer and water system was first placed in service in this area starting in the early 1800s. Most pipe from that era has been replaced, although we do have pipes that were installed in the 1850s still in service. The challenge is keeping in inventory replacements for pieces that break. Not surprisingly, in some cases we need to fabricate pieces to fit the particular situation, or reshape a curve or bend to accommodate how the system has settled over the decades. Each repair becomes somewhat of a unique operational episode, which requires remarkable creativity by our field crews.

Finally, after the break is found and repaired, the street must be filled and resurfaced. Water is nature’s great natural solvent, and the water bursting out of a pipe is at high pressure. The rock and gravel under the street can be loosened, which makes the street itself unstable. On Constitution, the surface asphalt was buckled by the force of the water underneath. Often, the harder part of the restoration is the street itself.

I am also reminded that the cost of these repair are classic emergency maintenance. Today, the line on Constitution is sporting a new 16 foot piece of 24 inch water main. Unfortunately, the rest of the line is still 82 years old. We are investing money and time in piecemeal fixes, rather than the capital funds to actually replace the entire older line. The latter is the priority, but the former must always be done in any event, and must always be funded as a result.

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One Comment

  • Hey George, we met at the recent water conversation in Philadelphia.

    This post made me think that it would be pretty interesting to hear how feasible it is to get extensive with monitoring in a city system. How pricey is it to drop some gauges all over the place.

    We really need to do it at the sewershed level to start, seriously, getting a handle on just how effective extensive LID design can be. I hear you about the inability of LID to deal with major events, but as you talked about all these pipes opening up I couldn't help but daydream about gauges going in all over the place with the new infrastructure.

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