Archive for the ‘infrastructure’ Category

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.”

All in a day’s — or night’s — work

On the shortest day of the year, the sun sets early, but you still need water. We’ll be there.

By Kristi Delynko

Dec. 21 is the winter solstice, the shortest day — and longest night — of the year in the Northern Hemisphere. And while many of us use an early sunset as an excuse to curl up on the couch with a good book or movie, some Denver Water employees will be hard at work — no matter how short the daylight hours.

Ensuring 1.4 million people receive high-quality drinking water is a 24/7 operation. Here’s a glimpse at what some of our employees will be doing long after the sun sets.

Emergency services conducts night work to repair a leak

A customer calls the emergency services dispatcher to report water bubbling up in the middle of a busy intersection. Even in the dark, members of the Emergency Services team are Denver Water’s first responders. They handle anything from shutting off water so crews can repair pipe breaks, to supporting Denver firefighters during multi-alarm blazes, to assisting customers with water quality complaints.

 

Daniel Ruvalcaba, senior utility technician, works on repairing an underground leak

Water mains burst when they want to, and usually at inopportune times, like when it’s dark and chilly. After Emergency Services responds to a call, a Water Distribution crew — including senior utility technician Daniel Ruvalcaba — fix the problem so customers can have water service restored as soon as possible.

 

Water treatment plant supervisor David Brancio

Long after many of us have gone to bed, staff at our four water treatment plants are hard at work. They gear up overnight when water use is low, to ensure the plants can meet customers’ needs during the day, when demand is higher. Our three drinking water plants and recycling plant are staffed around-the-clock by operators and maintenance personnel like water treatment plant supervisor David Brancio, who monitor the treatment processes and run lab tests to ensure the water we deliver (sometimes at the rate of 350,000 gallons a minute) meets all the federal and state regulations, and even tighter Denver Water standards.

 

Distribution operator Albert Geist monitors our complex water system

Coffee percolates and the dark room glows from monitors that cover entire walls in Systems Operations (also known as Load Control). Distribution operators like Albert Geist work 24 hours a day, seven days a week, scanning various computer screens to make sure our 30 treated water reservoirs, more than 3,000 miles of pipe, 160 pressure zones and 22 pump stations are ready for the morning load as our customers wake and prepare for their day. With a water system as large and complex as ours, pumps, facilities, even entire pipelines occasionally go down for service, maintenance or repair. Operators must constantly respond to alarms that signal potential real-time problems with everything from equipment and instrumentation to water quality and pressure.

We provide customers an average of 64 billion gallons of high-quality drinking water and 2 billion gallons of treated recycled water every year. No small task, but it’s all in a day’s — or night’s — work at Denver Water.

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.

Hidden underground, and ready to go with the flow

Whatever the demand, 30 storage tanks ensure reliable water delivery. Here’s how we keep them ready.

By Kim Unger

How many times do you turn on the faucet or flush the toilet every day? Is it the same amount, at the same time, every time? Probably not. No matter when or how often you need safe, clean water from your tap, it’s right there waiting. But how?

Underground storage tanks.

Inside a water storage tank

A peek inside one of Ashland’s new storage tanks. Construction is expected to wrap up in June 2017.

You may not realize it, but Denver Water has 30 tanks across our service area. They provide a buffer to allow our treatment plants to operate at consistent flows, while the tanks handle the highs and lows of water demands. This reduces energy costs and strain at the treatment plants, and it means that you never have to wait for treated water.

Just like pipes, dams and treatment plant equipment within our water system, storage tanks need maintenance and repairs to ensure reliability. Over the past few years, Denver Water has been replacing and upgrading the tanks, making sure we can provide water well into the future.

Take a look at this animated video to see how storage tanks work — and preview an upcoming project in southeast Denver.

In Waterton Canyon, Black Friday is for the birds

After nearly two years of sporadic closings, a major construction project is finally complete. Time for a Turkey Trot!

By Travis Thompson

In the spirit of the holiday, I want to give thanks for Waterton Canyon.

As an outdoor enthusiast with two young children, the canyon has become our family sanctuary. In 15 short minutes we can be on a trail — actually a Denver Water service road — large enough for the kids to ride their bikes without impeding others, while we gawk over the varieties of birds, reptiles and mammals along the way.

Like others who love the canyon, our time in this oasis has been limited since the spring of 2015, when the High Line Canal diversion dam, halfway up the canyon in the South Platte River, deteriorated to the point that it needed to be replaced.

Since then, it’s been nearly two years of intermittent, months long closures and restrictions on public access while crews worked to rebuild the dam.

It was a long and challenging process, but construction on the dam is officially complete.

 

On Nov. 25, hikers will be allowed back into the canyon just in time to burn off the Thanksgiving stuffing, gravy and sweet potato pie.

Just as grateful as I am for this recreational retreat next to the city, I’m even more grateful for the true purpose of the canyon: to provide 1.4 million people in the Denver metro area with clean drinking water.

As explained in “The ‘trails’ and tribulations of Waterton Canyon,” the No. 1 priority of this working facility is to store and send water to two of Denver’s three drinking water treatment plants. That means infrastructure maintenance and upgrades are frequent and must take priority over recreation.

In fact, the next weekday closure is already looming. A separate construction project wrapping up at Strontia Springs Dam, located at the top of the 6.5-mile canyon, involves heavy equipment, creating unsafe conditions for recreationists for the last three weeks of the year.

This certainly won’t be the last time the gates are closed to the canyon, either. So, here’s my advice:

1) Take advantage of the times when Denver Water is able to safely allow recreation on its service road. 2) If you see a wild turkey in the canyon the day after Thanksgiving, you might not want to look him in the eye.

Turkeys in Waterton Canyon

Wild turkeys, including these two, are frequently spotted in Waterton Canyon. Photo courtesy of Waterton Canyon enthusiast, Lori Bollendonk.

 

 

Into the dark, under the Divide and out the other side

Inspecting Roberts Tunnel: What it’s like going through a 23-mile concrete tube thousands of feet underground.

By Jay Adams

 

 

This is not your typical road trip. Twenty-three miles long and more than 4,000 feet underground, navigating Roberts Tunnel is more like driving a convertible through a car wash in the dark.

And for the Denver Water team that inspects this critical piece of infrastructure, it’s a big task, and not for the faint of heart.

Inspection Team left to right: Nate Soule, Lithos Engineering inspector; Tim Holinka, West Slope operations supervisor; Garret Miller, Roberts Tunnel supervisor; Doug Sandrock, safety specialist; Jay Dankowski, mechanic; Erin Gleason, dam safety engineer.

Inspection team (left to right): Nate Soule, Lithos Engineering inspector; Tim Holinka, operations supervisor; Garret Miller, Roberts Tunnel supervisor; Doug Sandrock, safety specialist; Jay Dankowski, mechanic; Erin Gleason, dam safety engineer.

Starting in Summit County, Roberts Tunnel carries water from Dillon Reservoir, under the Continental Divide and into the North Fork of the South Platte River in Park County before heading on to customers in Denver. Completed in 1962, the tunnel took 16 years to build and can deliver more than 480 million gallons of water a day to the Front Range. It’s nearly as long as the Chunnel under the English Channel.

“It’s an impressive piece of engineering,” said Erin Gleason, a Denver Water dam safety engineer. “We inspect the tunnel every five years to check for debris and look for any structural issues.”

On Sept. 21, a six-person inspection team went into the tunnel entrance at Dillon Reservoir and spent four hours driving through the 10-foot diameter passageway to the tunnel’s east portal, near the town of Grant in Park County.

“When we do tunnel inspections, we’re looking for shifts and cracks in the concrete lining,” Gleason said. “We compare notes from past inspections to see if there are any changes that could lead to future problems.”

Before the inspection begins, Denver Water drains the tunnel so the team can go through, but it’s not completely dry — especially at the entry point where the tunnel runs under Dillon Reservoir.

“It’s definitely wet at the beginning,” Gleason said. “Pressure from the water in the reservoir seeps through the rock and concrete and drains into the tunnel.”

The inspection team arrives at the tunnel's eastern portal near Grant in Park County.

The inspection team arrives at the Roberts Tunnel east portal near Grant in Park County.

While the water makes for a soggy ride, Gleason said seepage is not unusual to see inside tunnels and is not considered a major problem. The tunnel is basically dry after the first mile.

“We didn’t find any defects,” said Garret Miller, Roberts Tunnel supervisor. “It was a long ride, but this is something we have to do to make sure the tunnel can deliver water to our customers.”

A tunnel engineering consultant rode with the inspection team and declared the tunnel’s concrete lining to be in excellent condition.

“It’s really a team effort to pull off inspections like this, and we had an outstanding team,” Gleason said. “With regular inspections and maintenance, this tunnel will last well into the future.”

5 things you may not know about Chatfield Reservoir

This popular recreation spot also happens to be one of Colorado’s hardest-working bodies of water.

By Jessica Mahaffey

Are you a Chatfield junky?

As a long-time Littleton resident, I have fond memories of sailing, water skiing, swimming, fishing and camping at the reservoir with friends on my summer breaks from nearby Columbine High School (Rebel Pride!).

Today, I still enjoy afternoon walks on my favorite trails and take my two small dogs to the onsite dog park.

I’m hardly alone. Chatfield State Park is summer sanctuary in Denver’s back yard, welcoming more than 1.5 million visitors each year, according to Colorado State Parks.

The result: Nearly $10 million in economic impact to the communities within 50 miles of the park.

With all the pleasure it provides, many people may not realize that this is one hard-working reservoir, handling multiple duties and obligations. Here are five facts about Chatfield you probably don’t know:

album-101-21-south-platte-flood

Photo of the South Platte River flood of June 1965, looking due east.

  1. Chatfield was built for flood-control — not to store public drinking water.

It was built in 1967 by the U.S. Army Corps of Engineers in response to the 1965 flood of the South Platte River that cost more than $500 million and claimed 28 lives.

This reservoir can hold more than 350,000 acre-feet of flood water in emergency situations, but its current capacity is only 27,000 acre-feet of water, the equivalent of 8.8 billion gallons.

During drought conditions, water can be pumped from Chatfield to Marston treatment plant to supplement Denver’s public drinking water supply.

  1. Even though we don’t own or operate the reservoir, only water from Denver Water is currently stored behind the dam.

The U.S. Army Corps of Engineers owns Chatfield and leases the land to Colorado State Parks, which oversees day-to-day operations at Chatfield State Park.

Under a state agreement, Denver Water can fill Chatfield Reservoir with water, as long as we maintain water levels for community recreation.

  1. The water stored in Chatfield is used for water exchanges.

Think of an exchange reservoir as a bank. The water we “deposit” (store) at Chatfield can be used to “pay” (trade) downstream users with rights to the water, instead of sending it from our upstream reservoirs that supply Denver’s drinking water. This allows us to keep water higher in our reservoir system and to later deliver it by gravity to our water treatment plants.

  1. Chatfield provides recreational benefits beyond the obvious.

    Bypass flows released from Strontia Springs Reservoir located at the top of Waterton Canyon keep the river at optimum levels, sustaining a healthy trout fishery for anglers like the author’s brother Jason Kirk, pictured here.

    Bypass flows released through Waterton Canyon sustain a healthy trout fishery for anglers like the author’s brother Jason Kirk, pictured here.

In addition to preserving water levels for recreation, Denver Water uses its space in Chatfield to capture water it releases from Strontia Springs Reservoir, located a few miles upstream of Chatfield. These so-called “bypass flows” keep the river at optimum levels all year long, supporting the trout fishery in Waterton Canyon.

  1. Chatfield is about to take on even more responsibility.

The Army Corps of Engineers recently approved the Chatfield Storage Reallocation Project.  The project will increase water levels at the reservoir by about 12 feet, which is about 20,000 additional acre-feet, or about 6.5 billion gallons.

But this won’t be Denver’s water. Instead, it will help meet the water demands of growing populations in Centennial, Castle Rock, Castle Pines and other Front Range communities. It will also be used by farmers downstream of Denver. Denver Water will still maintain its original storage pool of more than 27,000 acre-feet and will remain involved in the overall operation of Chatfield after the reallocation is completed.

But that’s not all. The Chatfield Reservoir Mitigation CompanyColorado Parks and Wildlife and the Colorado Water Conservation Board are developing a plan for an environmental pool to provide up to 1,600 acre-feet of storage. But there is room for more. Learn more about Denver Water and The Greenway Foundation’s effort to provide more water for fishing, farmers and fun on the South Platte: Not your average pledge drive.

So whether you are a Chatfield regular like me or someone who simply enjoys driving by it from time to time, I hope knowing more about Chatfield Reservoir increases your appreciation for this metro-area amenity.

Chatfield Reservoir can hold more than 350,000 acre-feet of flood water in emergency situations, but its current capacity is only 27,000 acre-feet of water, the equivalent of 8.8 billion gallons.

The water levels at Chatfield Reservoir will increase by about 12 feet, which is about 20,000 additional acre-feet, or about 6.5 billion gallons.

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