Posts Tagged ‘infrastructure’

Breaking point: Temperature swings tough on water pipes

With the ups and downs of winter weather in Colorado, repair crews are clamping down on main breaks across Denver.

By Jay Adams

 

 

Denver winters can feel like a rollercoaster ride — cold and snowy one day, mild and sunny the next. All those ups and downs make for interesting weather forecasts, but those temperature swings also take a toll on water mains under city streets.

Through Dec. 20, Denver Water crews had fixed more than 318 water main breaks this year. Of those, nearly 20 percent were linked to dramatic changes in temperature.

Temperature breaks, technically called “shear breaks,” are caused when the ground shifts due to changes in the weather.

Shear breaks occur during prolonged cold spells and fast warm-ups.

When temperatures drop, the ground freezes, causing water molecules inside the soil to expand. The longer the temperature stays below freezing, the deeper the frost layer stretches below the surface. The frozen soil puts stress on top of the pipes and can cause them to crack.

A pipeline mechanic removes dirt from a broken water main to identify the leak.

A pipeline mechanic removes dirt from a broken water main to identify the leak.

Pipes are also prone to crack when the weather warms up quickly after a cold spell. As the ground warms, the water molecules shrink and the ground shifts.

“The ground freezes and thaws all the time during the winter here in Denver,” said Ed Romero, water distribution foreman. “Any little bit of movement in the ground can end up splitting a pipe.”

Crews can identify a temperature break because the crack looks like a line was drawn around the pipe with a marker.

Older pipes are more vulnerable to temperature breaks due to the ongoing stress of the freeze and thaw cycle over time.

Denver Water crews can usually fix a temperature break by digging up the street and placing a stainless steel repair clamp around the crack on the pipe.

Pipeline mechanics bolting on a repair clamp, which is commonly used to fix water mains after temperature breaks.

Pipeline mechanics bolting on a repair clamp, which is commonly used to fix water mains after temperature breaks.

“Repair clamps are very effective ways to fix broken water mains after a temperature break,” Romero said. “The clamp forms a tight seal and will not let any water out of the pipe.”

When pipes are replaced or installed, Denver Water reduces the risk of temperature breaks by putting a sand-gravel mix around the pipes to provide a cushion when the ground shifts.

Temperature swings and ground shifts are just one cause of water main breaks. Other factors include age and material of the pipe, corrosion, the type of soil and the amount of water pressure running through the pipe. All of these factors can weaken sections of the water main and lead to more complicated breaks and repairs.

“We see lots of temperature extremes here in Denver and lots of different types of pipe breaks,” Romero said. “Some breaks are easy to fix, others can take hours, even days to repair.”

Your water bill is going up (slightly). Here’s why

That small increase helps us make big system upgrades, ensure water reliability and plan for future needs.

By Steve Snyder

 

Nobody likes to pay a bill.

No matter how much you like a service or how essential it may be, handing over your hard-earned money to somebody else — particularly if that bill often increases from year to year — is never fun.

But when it comes to your water bill, the simple fact is the cost of running a complex water system continues to rise. Your bill helps to maintain and upgrade a vast infrastructure that allows us to collect, treat and deliver safe, reliable water, while also providing for essential fire protection services.

You’ll see some slight increases in your water bill starting April 1, 2017. Here are the answers to three questions you may be asking:

  1. Why are you raising my rates?
crews placing concrete for storage tank at Hillcrest

Crews work to place the concrete floor of one of the new Hillcrest treated water storage tanks on Dec. 10. Denver Water is in the middle of a $100 million project to improve the safety and reliability of its Hillcrest facility by replacing two 15-million-gallon underground water storage tanks with three 15-million-gallon tanks, and a pump station.

We have a large, intricate system with a lot of aging infrastructure. With a 5-year, $1.3 billion capital plan, we’re staying on top of the upgrades and new projects needed to keep this system running.

(Watch the video at the top of the page to see the kinds of projects, like replacing failing underground storage tanks and aging pipes.)

To keep up with this necessary work, we are increasing the monthly fixed charge on your bill to help us even out our revenues over the year so we can repair and upgrade our system. This means less reliance on revenues from how much water customers use, which has become increasingly difficult to predict in recent years given the more frequent and extreme weather fluctuations.

  1. How much is my water bill going up?

That depends on the type of customer you are and how you use water. Your bill is comprised of a fixed monthly charge and charges for how much water you use.

Every customer will see an increase to their monthly fixed charge. If you’re like most residential customers who have a 3/4-inch meter, that charge will increase from $8.79 to $11.86 per month.

To help offset the fixed monthly charge, the charge per 1,000 gallons for many customers will see a small decrease in 2017.

Adding up those two elements, if you live in Denver and use 115,000 gallons of water a year in the same way you did in 2016, you can expect to see an annual increase of about $29, which averages out to a monthly increase of about $2.40 a month. (Summer bills are typically higher because of outdoor water use.)

If you live in the suburbs and get your water from one of our 66 distributors, your bill will be higher than Denver resident’s. That’s because the Denver City Charter requires that suburban customers pay the full cost of service, plus an additional amount.

  1. You ask me to use less water and then raise my rates. Am I being penalized for conservation?

We always encourage conservation and the efficient use of water. In fact, rates would be higher without our customers’ conservation efforts; we’d have to build more treatment and distribution facilities to keep up with the demand for water.

For example, your conservation efforts are saving Denver Water an estimated $155 million on a new treatment plant and storage facilities because it doesn’t have to be as big as we originally estimated. That’s $155 million we don’t have to recover through rates and charges.

No one likes paying higher bills, but consider the overall value of water. Most Denver Water customers will still pay about $3 for 1,000 gallons of water.

And while rates are going up, Denver Water is committed to keeping water affordable, particularly for the essential indoor water use that is vital for drinking, cooking and sanitation. In 2017, customers will continue to pay the lowest rate for what they use indoors.

 

If you’d like to talk over your bill with someone, contact Denver Water’s Customer Care team at 303-893-2444, and a representative will help you calculate your individual bill impacts, based on your personal water-use information.

Why is all that water pouring into the street?

Flushing stagnant water out of our hydrants, all in the name of high-quality H2O.

By Steve Snyder

 

Steve Lovato gets the same question all the time.

“Why are you wasting water, especially if we’re in a drought?”

As a system quality supervisor for Denver Water, Lovato is charged with flushing more than 3,000 hydrants and blow-off valves in our distribution system. That means he opens hydrants all around the metro area — letting lots of water rush out onto the streets.

Why?

“These hydrants sit at the end of a water main, so water isn’t constantly circulating like in other parts of the system,” said Lovato. “When water sits in a pipe too long, the quality isn’t as high as when it leaves our treatment plants. Flushing the hydrants brings that water quality back to where we want it.”

So every year from April to October, Lovato and his team open hydrants to get rid of stagnant water, but not without a lot of preparation first.

“We look at the size and length of the water mains before we go out, so we have a good idea of how much water it will take to flush a particular area,” Lovato said.

On average, about 1,000 gallons of water is flushed before the water is back to Denver Water standards. That amount represents a very, very small amount of our total annual consumption — about 0.01 percent.

But as you can imagine, opening hydrants in a busy area tends to draw a crowd, so the crews put up signs and hand out informational pamphlets explaining what Denver Water is doing and why.

And boy, do people love to watch.

“We have kids come up to play in the water,” Lovato said. “We have people who fill buckets to put on their gardens and lawns.”

And yes, people ask him why we’re “wasting” so much water.

“They have a lot of questions, but when we tell them we are making sure they have high-quality water, they are very accepting of what we are doing,” Lovato added.

As the hydrants spew water, Lovato watches for clarity, while testing the temperature and water-quality levels. When everything meets Denver Water’s standards, Lovato seals the hydrant and moves on to the next stop. Each hydrant takes about 10 to 15 minutes to flush. But the impact is more lasting.

“It’s important to make sure people have great quality water,” Lovato said. “That’s the thing I love about my job.”

Labor Day the Denver Water way

Employees work 24/7 to keep the water flowing.

By Denver Water staff

The need for water doesn’t shut off on weekends or holidays — including Labor Day. So while many folks are enjoying a day off from work Monday, employees from disciplines across Denver Water will be on the clock.

Whether responding to a main break or performing daily tasks that can’t skip a day, we have many employees who cover shifts 24/7 to ensure our customers always have clean, safe water to drink.

Learn who they are.

Note: This slideshow may not work depending on the type and configuration of your Web browser. If that’s the case, click here to view it.

Looking for ‘hot spots’ — in all the right places

New analysis pinpoints water mains at risk, allowing crews to upgrade whole neighborhoods at once. 

By Travis Thompson

Denver Water crew installs a new 12-inch-diameter pipe as part of 2015 pipe replacement program in southeast Denver neighborhood.

A Denver Water crew installs a new 12-inch-diameter pipe as part of the 2015 pipe replacement program in a southeast Denver neighborhood.

When a water pipe breaks under the road, there’s no telling what it’s going to do. Some shoot geysers into the air large enough to make Old Faithful jealous. Others turn neighborhood streets into muddy rivers, and some barely send a trickle of water up through the cracks in the pavement.

But even if there isn’t major disruption when the pipe breaks, there will be when it’s time for the repairs. Work crews can’t fix a pipe buried eight feet underneath the street without creating some commotion, from traffic disruptions to noisy equipment and temporary water outages.

Knowing emergency repairs can be a headache — especially when they happen in front of your home — Denver Water is always looking for ways to improve the repair process.

Enter Peter Kraft. As Denver Water’s asset manager, his job is to track and examine infrastructure conditions and needs throughout the water distribution system. Kraft recently analyzed about 630 breaks in Denver Water’s service area since 2013, using locations, type of pipes, installation years and other data to identify areas that he calls “hot spots.”

The research led him to neighborhoods on the west end of Centennial that have experienced 18 breaks in two years, over a 12-mile span. That’s more than three times the number of breaks as the rest of Denver Water’s service area.

Sensing an opportunity, Kraft and Mike Mercier, supervisor for the crews who replace sections of pipe each year, devised a new scheme. Instead of only upgrading pieces of “bad” pipe speckled throughout the water distribution system, the pipe replacement team will concentrate its efforts on one area.

This map shows the locations of 18 breaks across 65,000 feet of pipe in west Centennial since 2013.

This map shows the locations of 18 breaks across 65,000 feet of pipe in west Centennial since 2013.

This new approached kicked off in March, and crews will replace about 60,000 feet of pipe throughout the targeted 12-mile zone east of South Broadway along Arapahoe Road over the next two years.

“Though we’ve mapped out additional work in this area, it will be more prudent for us to see how the first couple of years go and adapt, if needed,” said Kraft. “As we learn from doing work in that area and also advance our analysis techniques, we may find there is a different ‘hot spot’ that boasts even higher value for us to concentrate on.”

Even though the work is cumbersome, the crews are coordinating their efforts and communicating with residents before the disruptions occur.

Kraft said he hopes this new strategy will help reduce issues like one seen in early March, when a 12-inch-diameter pipe broke in an east Denver intersection — just feet from where a new piece of pipe was upgraded less than a year earlier.

“There is no exact science when trying to guess the condition of a pipe underneath the road,” he said. “But by identifying these hot spots across the system, we can concentrate our resources on larger areas so we don’t have to return to deal with a main break in a community where we recently worked.”

So while Denver Water trucks will be common sight over the next few years in west Centennial, the upgrade will rid the community of its “hot spot” moniker, leaving the geyser shows for vacations in Yellowstone National Park.

 

 

Releasing water in the middle of a drought?

California does it, and so do we. It’s all part of managing a complex water system.

By Dana Strongin

Even in times of severe drought, sometimes a water system has to know when to let go.

Consider the conundrum in water-challenged California, where operators recently doubled the amount of water flowing out of federally run Folsom Lake, a Northern California reservoir.

“You can’t hold on to every drop,” said Shane Hunt, a spokesman for the Bureau of Reclamation, which runs Folsom.

AnteroJune2015_close

Water drains out of Antero Reservoir in June 2015 as part of preparations to rehabilitate Antero Dam.

Why would a water system release such a precious resource? We put the question to Nathan Elder, water resource engineer at Denver Water.

“The main benefit of drawing a reservoir down early is to be able to control releases from the reservoir,” Elder said. From a system view, opening space in one reservoir may create the flexibility to fill all of the reservoirs during the runoff season.

Call it science or a miracle, we are blessed to have the gift of Mother Nature’s snows as our primary source of water.

Denver Water’s mountain collection system spans about 4,000 square miles and houses a lot of infrastructure — facilities that cannot all be online all of the time. Maintenance and improvement projects, such as upgrading the outlet works at Dillon Reservoir and rehabilitating Antero Dam, are critical to keep the system working well into the future.

Operating reservoirs requires careful thought — including balancing many other important considerations, such as water supply, safety, recreation, the environment and hydropower.

With all of the complexities our planners consider, they can count on one simple fact: Every spring brings warmer weather, and most of the mountain snow will melt. We need a place to put that water to store it for future use.

DillonMay2009_making_room

Dillon Reservoir sits low in May 2009, after operators released water to make room for runoff.

Dillon Reservoir offers a good example. In early February 2014, when Dillon was 94 percent full, we started to make room for the robust runoff expected with snowpack at 163 percent of normal. And in late January 2015, because the reservoir was 99 percent full and we had a healthy snowpack, we began to slowly lower the reservoir.

It’s starting to happen again this year. Dillon Reservoir is 93 percent full, and snowpack above it is 108 percent of normal. In late February we began letting out more water to slowly decrease the reservoir level and benefit hydropower production at the same time. It’s possible we could decide later to release water at a higher rate to make more room for runoff.

But it’s way too early to know for sure. Denver Water operators keep their eyes on the skies and weather forecasts so they can stay nimble if conditions change quickly.

Either way, releasing reservoir water is not necessarily a loss. “Water released from Dillon is used to generate hydropower,” Elder said. “If conditions present themselves, releases can be managed and timed to prolong rafting season on the Blue River.

“The water may not go to customer’s taps, but that does not mean it is not put to use.”

A sure sign of winter: Closing up the Morning Glory spillway

Capping the summer maintenance season at Dillon Reservoir takes expert work crews, planning — and a really big plug.

The 6-ton steel plug is carefully placed into the Morning Glory spillway at Dillon Reservoir

The 6-ton steel plug is carefully placed into the Morning Glory spillway at Dillon Reservoir

By Matt Wittern

How do you keep debris and cold temperatures from damaging a giant spillway that measures 15 feet in diameter and features a more than 200-foot drop?

Get a really big plug.

That’s what happened on Nov. 6, when Denver Water crews placed a 6-ton steel plug into the Morning Glory spillway at Dillon Reservoir. The annual activity marks the end of summer and signals the start of winter maintenance season, when Dillon Dam’s caretakers focus on maintenance of the structure’s interior facilities.

The plug serves a primary and secondary function — first, it prevents cold air from entering the spillway, which could damage the outlet works and take hours of manual labor to melt the ice that builds up. It also helps prevent chunks of ice and snow from falling into the spillway and crashing more than 200 feet below.

The plug helps prevent chunks of ice and snow from falling into the spillway.

The plug helps prevent chunks of ice and snow from falling into the spillway.

Timing of the operation varies from year to year, though the rule of thumb is to do it when the reservoir’s water level is at least four feet below the crest of the spillway.

“That way, we have time to get back in here and remove the plug should we get sudden, unexpected inflows,” said Rick Geise, caretaker at Dillon Reservoir.

The cap was placed using a mobile crane provided and crewed by Terry’s Crane and Rigging out of Salida, Colorado; the company has provided this service to Denver Water for more than 15 years. Denver Water employees Rick Geise, Donald McCreer and Nate Hurlbut assisted, overseen by dam and hydropower plant supervisor John Blackwell.

“One of the best things about Dillon’s operations is its complexity. My team and I are involved in so many different types of projects that our job is never boring,” said Blackwell. “With good planning and the ability to adapt, projects like this one are not necessarily difficult — especially when you have a crew who are experts in performing their tasks safely and efficiently like we do here.”

Come early spring, Blackwell, the crane and crew will be back again to pull the plug, signaling the start of the summer maintenance season, where the dam’s crews will focus on larger capital improvement projects to keep the facility in tip-top condition.

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A view of the spillway cap installation from Dillon Dam.

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