Main breaks 101: Raising our infrastructure GPA

Learn more about why pipes burst, how much water is lost and what Denver Water is doing about it.

February 13, 2017 | By: Travis Thompson
Crew draining water from hole after main break.
A Denver Water crew drains water from a hole caused by a 24-inch-diameter conduit break before repairing the pipe that ruptured in the Highlands on Jan. 28, 2017.

With a significant portion of our system installed right after World War II, Denver Water is no stranger to main breaks — as Denver witnessed in late January when a nearly 130-year-old pipe ruptured in the Highlands.

An estimated 10 million gallons of water was lost when the 24-inch-diameter pipe burst.

These unfortunate situations are a part of operating a water system, and we’re not alone.

The American Society of Civil Engineers’ grade for America’s drinking water infrastructure is a D, which is no surprise considering there are 240,000 water main breaks each year in the U.S.

In Denver, we’re working hard to limit these issues and help raise the GPA of the nation’s water infrastructure.

Check out the curriculum for Main Breaks 101:

Home Room — The basics.

Denver Water operates and maintains more than 3,000 miles of pipe — enough to stretch from L.A. to New York. The pipes that carry clean drinking water to your home vary in size, from ½-inch-diameter service lines to a 108-inch-diameter conduit.

Cracks and breaks occur based on the condition of the pipe and its surroundings — including age, pipe material, how corrosive the soil is, water flow, temperature and more.

“Every main break is different, but fixing it safely and quickly are always our top priorities — to minimize disruption to our customers who live, work or commute in the area, and to make sure we lose as little water as possible,” said Tom Roode, Denver Water’s chief operations maintenance officer.

Crew repairing 16-inch water pipe.
In 2016 Denver Water repaired 326 main breaks, including this 16-inch-diameter water pipe that burst along East Sixth Avenue on Nov. 11, 2016.

Accounting — Water lost.

Denver Water treats more than 60 billion gallons of water a year, and estimates that less than 1 percent of that water is lost to breaks and leaks we find and repair.

“While water loss due to undetected leaks and main breaks is inevitable, our goal is to proactively locate those leaks and respond quickly to water main breaks across our system,” said Roode.

Math — Calculating water lost.

How do we know how much water is lost through main breaks and leaks? Without a water meter attached to a main break — which isn’t a viable option — we have to rely on calculations that factor in the size of the pipe, cause of the break, average flow rates and average water shut-off times. Here’s how some of the numbers break down:

  • ¾-inch service line leak = 15,000 gallons
  • 6-inch main break = 30,000-156,000 gallons
  • 8-inch main break = 35,000-252,000 gallons
  • 12-inch main break = 45,000-378,000 gallons
  • 16-inch main break = 52,000-1,125,000 gallons

Applied Science — What we’re doing about it.

To minimize water loss, Roode said Denver Water has numerous programs in place to proactively identify and minimize leaks, and upgrade and repair the aging water system, including:

  • Crew installing new pipe
    Denver Water installs a new section of pipe in Greenwood Village during the summer of 2016.

    Leak detection — This program has saved an estimated 138 million gallons of water over the past 5 years. Underground (non-surfacing) leaks found through our leak detection program account for about 0.03 percent of our treated water.

  • Pipe replacement — We proactively install or replace an average of 60,000 feet of pipe throughout our service area per year. In 2016, about $11 million went to main replacement and main improvement. Denver Water will invest about $130 million in main replacements over the next 10 years.
  • Pressure regulating valve maintenance and replacement  This program allows us to replace or repair the valves that regulate the 160 pressure zones in our system, reducing the number of main breaks caused by these valves.
  • Corrosion control  We have more than 4,000 test sites on pipes throughout our system to help us calculate the rates of corrosion and decide which pipes need to be replaced before they cause major damage.

Homework — How can you help?

You already do! Your water rates fund the programs to maintain, upgrade and replace our aging system, helping us ensure we provide you and the 1.4 million people we serve with clean, safe water every day.

If you see what may appear to be a leak in the street, give our emergency dispatchers a call at 303-628-6801.

 

Visit Denver Water’s website to learn how to troubleshoot problems and fix leaks at your home or business.

5 thoughts on “Main breaks 101: Raising our infrastructure GPA”

  1. If we have 3,000 miles of pipe (15,840,000 feet) and replace 60,000 feet a year, it will take us 264 years to replace all the pipe we’ve got in place. So, new pipe laid today will need to last until the year 2281. Is this right?

    1. On the surface, your math appears to be correct, but there is much more to our proactive pipe replacement program than just removing old pipe. Just because a pipe is old doesn’t mean it needs to be replaced. We have pipe more than 100 years old functioning just as well today as it did when it was new. Denver Water pinpoints “hot spots” in our system based on location, pipe type, installation dates and other data. This allows us to be more strategic so we can get the most out of ratepayer money.

      Currently, Denver Water is replacing a 12-mile zone of pipe in Centennial on pipe installed in the 1950s and 60s. Learn more about Denver Water’s pipe replacement program and the work at this hot spot here.

    1. While it may seem like a drop in the bucket, it’s vital that we are responsible and strategic with ratepayers’ investment into the system. Whenever you’re talking about infrastructure buried underneath the street, it’s costly and disruptive to replace.

      Our strategy with respect to asset management is to minimize the life cycle cost of the pipes in our system. Ideally, we’d replace a pipe one day before it was expected to fail, but that is all but impossible to do. We’re balancing the concept of minimizing life cycle costs against our level-of-service goals that include factors such as water outages, customer inconvenience, etc.

      It’s important to note that just because a pipe is old it doesn’t mean it needs to be replaced. For example, the life span of ductile iron pipe is generally estimated to be in the 100 plus year range. The life span of PVC pipe is generally estimated to be in the 75 year range, although some recent research has suggested that 100 years might be possible. The life span will be heavily influenced by such factors as quality of pipe and installation, soil type, operating pressure, variability of operating pressure, among other factors.

Post a Comment

Your email address will not be published. Required fields are marked *