Archive for the ‘Snowpack’ Category

Early season turnaround bodes well for water supply

Despite a parched start to winter, snowpack levels are on track thanks to a snowy December and early 2017 storms.

Denver Water's Winter Park crew works around the clock to ensure facilities are accessible during snowstorms.

Denver Water’s Winter Park crew works around the clock to ensure facilities are accessible during snowstorms.

By Travis Thompson

Like carpenters, water supply managers use an assortment of tools to get the job done. But instead of tape measures and hammers, their tool boxes are filled with charts and graphs, computer models and good old-fashioned experience.

With 80 percent of Denver’s water supply coming from snowmelt, no tool is used more during the winter months than the charts showing snowpack levels in the mountains above Denver Water’s facilities.

And this year is proving to be one of the more interesting in recent memory.

With more than half of the snow season still ahead, water managers have already seen near historic lows and highs to kick off the winter.

“Our team was starting to sweat a little bit this fall — literally and figuratively — with the unseasonably warm and dry weather,” said Dave Bennett, water supply manager for Denver Water.

In late November, snowpack levels in areas feeding the streams and rivers that flow into Denver’s mountain reservoirs were only 10 percent to 20 percent of normal.

Denver Water’s reservoirs were still above average because of the good water years carried over from 2014 and 2015, as well as efficient water use in the Denver metro area.

But the dry start to winter had Denver Water planners on edge.

“I knew that a couple of good storms would have us back to normal,” said Bennett. “It was too early to panic — well, that’s what I kept telling myself at least.”

Thankfully, he was right.

On Jan. 5, water supply manager Dave Bennett talked to 9News reporter Colleen Ferreira about the improved snowpack levels in Denver Water's collection area.

On Jan. 5, water supply manager Dave Bennett talked to 9News reporter Colleen Ferreira about the improved snowpack levels in Denver Water’s collection area.

In December, Denver Water’s Colorado River basin collection area received almost double the amount of accumulation than normal, with approximately 60 inches, making it the sixth snowiest December for this area over the past four decades.

Similarly, the South Platte River basin collection area that feeds Denver’s reservoirs received approximately 40 inches of snow compared to the normal 20 inches, making it the fifth snowiest December in this location over the same 40-year time period.

Couple that with the early 2017 snowstorms, and snowpack levels are now 137 percent and 128 percent of normal in the Colorado River and South Platte River watersheds — and, it’s still snowing!

It was such a significant turn of events that Bennett was featured on 9News, talking about the importance of the recent snow, not only for water supply but also for Colorado’s greatest asset: outdoor recreation.

“I’ve never seen an early season turnaround like it,” said Bennett. “But we still have a long way to go. A lot can happen between now and spring — the months we rely on the most for snowpack are still ahead of us.”

snowpack-combined-stacked

Weekend snowstorm delivers big shot of moisture

By Jay Adams

 

 

It was tough to shovel, but last weekend’s wet, heavy snow delivered a three-day punch of liquid gold for Denver Water.

The storm ramped up on April 15 and finally cleared out on April 17. When it was over, 2 to 4 feet of snow pounded areas of Boulder, Grand, Jefferson, Park and Summit counties where Denver Water captures the snow that produces up to 80 percent of our water.

In just 72 hours, the snowpack shot up 15 percent in the Upper South Platte River basin and 9 percent in the Upper Colorado River basin. As of April 18, the snowpack for the South Platte and Colorado River basins stood at 109 and 113 percent of normal, respectively.

SP_SnowpackCO_Snowpack

 

 

 

 

 

 

 

“This weekend’s snowstorm was really good for our snowpack,” said Bob Steger, manager of raw water supply. That heavy, wet stuff produced around 2 inches of snow-water equivalent — a measure of how much water comes out of snow when it melts. To put that in perspective, the water gained from the three-day storm accounts for 16 percent of the snow-water equivalent in the South Platte River basin so far this season.

Gross Reservoir in Boulder County received nearly 3 feet of snow during the April 2016 snowstorm. The reservoir is expected to fill to capacity later this year.

As temperatures rise later this spring, the snowmelt will reach Denver Water’s mountain reservoirs. Steger expects 10 of Denver Water’s 12 major reservoirs to fill (two won’t be filled due to construction projects).

The bulk of the storm hit the Front Range — a typical spring pattern during an El Nino year — but that also brings benefits to both eastern and western Colorado. “A storm like this weekend’s means we don’t have to bring as much water over the Continental Divide, so more water stays in West Slope creeks and streams,” Steger said.

The moisture in the metro area also means good things for Denver Water customers. Late-season snow in the city means people don’t have to start watering their lawns as early as they do in a warmer, dry spring.

Steger said Denver Water’s annual watering rules, which kick off May 1, serve as good guidelines to follow in our unpredictable climate.

“The rest of this spring we could see a dry spell or more moisture like last year,” Steger said. “We all have to remember, we live in Colorado. Almost anything can happen with the weather.”

Snowpack totals? It’s all part of March Madness

Hammered by this month’s snowstorms, Summit and Grand counties provide a big boost to our water supply.

By Jay Adams

 

 

March in the Colorado Rockies can be as wild as a half-court buzzer beater in the NCAA Basketball Tournament.

The first week of the month was dry and unseasonably warm. The second week brought a bounty of snow, and some parts of Summit and Grand counties picked up more than 30 inches. Week three saw 70-degree temperatures in Denver, followed by a blizzard and more heavy snow in the mountains.

Call it our own version of March Madness.

That kind of volatile spring weather is why Denver Water’s planning team remains cautious about predicting the snowpack yield until mid-to late-April. “Weather in March is like the basketball tournament,” said Nathan Elder, water resource engineer. “We really don’t know what we’re going to get every year.”

The frozen Snake River east of Keystone is one of Dillon Reservoir's three main tributaries.

The frozen Snake River east of Keystone is one of Dillon Reservoir’s three main tributaries.

The latest storm delivered impressive snow totals at Denver Water locations. Gross Reservoir in Boulder County picked up 20 inches of wet snow, which contained 2.13 inches of water. Strontia Springs Reservoir in Waterton Canyon received 13 inches of snow with 1.43 inches of water and Cheesman Reservoir in Douglas County received 10.5 inches of snow with 1.07 inches of water content.

Mountain snow provides 80 percent of Denver Water’s water supply (rain accounts for the rest), and March and April alone produce an average of 25 percent of the collection system’s annual precipitation.

“The snow we’ve been getting over the past two weeks has been really good for the mountain snowpack,” said Elder. “We’ve definitely seen a nice spike upward on the charts this month.”

It certainly didn’t look that way earlier this year. “Across most of February and early March we had warm temps and dry conditions and melted quite a bit of snow,” said John Blackwell, Dillon Reservoir operations manager. “But now winter’s back, which is creating a bit of madness here in Summit County.”

Snowpack — in the areas of the Upper Colorado and South Platte River basins where Denver Water captures its snow — was above normal in December and January, below normal in February and then back above normal in late-March.

Colorado River March 24 snowpackSP March 24 snowpack

On March 14, snowpack in the Colorado River basin stood at 100 percent of normal and snowpack in the South Platte River basin was 95 percent of normal. After two weeks of snow, the two basins shot up to 109 and 107 percent respectively, on March 24.

March and April are critical months for deciding whether the year’s snow totals will produce a championship season of water, or merely play runner-up to previous years.

While this year’s snowpack is looking good, it will likely fall short of the all-time championship seasons in Denver Water’s collection areas. Snowpack peaked at 166 percent of normal in the Colorado River basin in 1984 and an incredible 203 percent of normal in the South Platte basin in 1997.

Even in an average snow year, it’s common to see ups and downs on the snowpack charts. “Some years you’re constantly hit by small storms, other times you get nailed with one huge storm like we did in the spring of 2003,” Elder said.

Dillon Reservoir in Summit County stood at 93 percent full on March 21, 2016. The historic median for this time of year is 87 percent.

Dillon Reservoir in Summit County stood at 93 percent full on March 21, 2016. The historic median for this time of year is 87 percent.

Denver Water’s reservoir levels are above average for this time of year, and Blackwell hopes more snow this spring will fill Dillon Reservoir this summer. “We’re still cautious, we’re optimistic, and the next couple weeks are critical,” he said.

With more snow in the forecast for the last week of March and the National Weather Service’s Climate Prediction Center showing a 40 percent chance of above-average precipitation for most of Colorado in April, the rest of the snow season is looking good. “We’re getting there,” Elder said. “We can’t say we’re good yet, but we are heading in that direction.”

Why we love juicy flakes (and you should, too!)

Not all snowflakes are created equal; some have more love to give.

By Jay Adams and Kim Unger

When the snowflakes begin to fall, we’re guessing the last thing on your mind is moisture content. Isn’t all snow created equal? Turns out, there is a big difference between the type of snowflake and how much moisture it will produce — which makes a difference in filling our mountain reservoirs. Check out our infographic to see why juicy flakes are best.

 

infographic-snowflakes-waterContent-reservoirs-v6

El Nino: Helping hand or just a lot of hot air?

Snow in Colorado. Rain in California. Is El Nino the cause, and can it keep the water coming?

By Steve Snyder

Too big to fail.

No, this isn’t about enormous financial institutions. We’re talking about the biggest, baddest El Nino weather pattern we’ve seen in years.

This year’s version of the warming surface water in the Pacific Ocean was supposed to blast much of California and other western states with potentially record-setting moisture. If you’re keeping up with climate news, California in particular could use the water.

This map of a typical El Nino weather pattern shows Colorado right on the edge of moisture impacts. (Courtesy: National Weather Service)

This map of a typical El Nino weather pattern shows Colorado right on the edge of moisture impacts. (Courtesy: NOAA)

And so far, so good, at least in terms of moisture content. But the key words are “so far,” as even this supersized El Nino hasn’t made a huge dent in the Golden State’s decade-long drought.

So why is Denver Water watching the weather in California so closely? One reason is that water resources for Colorado and California are closely linked. Any moisture California gets is good for Colorado and the entire Colorado River Basin.

We’ve seen a lot of moisture in Colorado this winter, too, and it has really helped our snowpack. But how much is our winter wonderland related to our warm-blooded friend in the Pacific?

“It’s difficult to credit El Nino for all of our weather this winter,” said Laurna Kaatz, climate adaptation program manager for Denver Water. “El Nino typically increases precipitation across the southwest, and our Rocky Mountains are right on the fringe of this area. So El Nino can influence our weather, but it’s not the only factor.”

It’s also difficult to predict what the rest of the winter and early spring will bring in terms of moisture for Colorado, as each El Nino pattern is different. But there are some historical patterns to study.

“Past El Nino cycles have usually brought moisture to Southern Colorado,” Kaatz said. “The three-month outlook calls for above-normal precipitation in Colorado, but nothing is certain here in terms of weather, given our location and topography.”

Of course, as long as the snow keeps piling up in our mountains, we don’t care if it’s El Nino or El-Nacho Libre causing the stir. We’ll take all we can get, especially with Colorado’s unpredictable weather.

Why Denver Water loves snow

Snow far, snow good: Winter snowpack off to strong start — where there’s snow, there’s water.

By Jay Adams

 

 

What’s good for skiers is good for reservoirs. If you’ve already hit a few powder days on the slopes this year, you know the winter of 2015-2016 is off to a snowy start in the mountains.

As of Feb. 16, the amount of snow in the Colorado and South Platte river basins stands at 110 and 114 percent of normal respectively for this time of year, according to the Natural Resources Conservation Service. This is good news for Denver Water, as the mountain snow in these two river basins is the primary source of our drinking water supply.

Denver Water caretaker Per Olsson snowshoes through the woods to access snow-measuring sites.

Keeping track of how much snow is in the mountains is a team effort. From January through May, our crews make a monthly trek into the wilderness and measure snow at 11 locations in Grand, Park and Summit counties. They hike, snowshoe, cross-country ski and ride in snowcats to reach our snow-measuring sites.

“It’s fun to see how much snow we are going to get every year,” said Per Olsson, Jones Pass caretaker. Olsson has been measuring snow at Denver Water for 25 years, including several locations in Grand County. “We’re hoping for a lot of snow this year, and so far it looks good.”

In late January, Olsson and Conor Peters, a water monitoring specialist, strapped on snowshoes and trudged through the forest for a monthly check of the snowpack at the base of Berthoud Pass near Winter Park.

00025.MTS.00_00_12_29.Still001

Olsson (left), and Conor Peters, measure snow density, depth and weight at the base of Berthoud Pass. Records of snow have been kept at the site since 1936.

Measuring snow requires more than just checking how much is on the ground. Olsson and Peters use a special tube to measure the depth, density and weight of the snow at seven locations on the Berthoud Pass snow-measuring site.

The courses provide water planners with eyes-on-the-ground information to compare 2016 numbers with snowpack levels dating back to 1936.

They use that information to determine the snow-water equivalent: a calculation of how much water is packed into the snow. “A general rule of thumb is that 12 inches of snow equals about 1 inch of water when it melts,” said water resource engineer Nathan Elder.

Denver Water also uses information collected by the Conservation Service’s automated snowpack telemetry weather stations, known as SNOTEL sites. The network of stations was established in 1979 and provides real-time snow information at locations across Colorado and the western U.S.

Olsson has worked at Denver Water for 25 years.

Olsson has worked at Denver Water for 25 years.

The manual and automated readings provide Denver Water’s planners with a picture of how much and what type of snow is in the mountains. They use the information to make predictions about how much water will end up in Denver Water’s reservoirs during the spring runoff.

Despite the strong start to the winter, planners don’t make early assumptions. “This year is looking good so far,” Elder said. “We like to see snow any time of year, but March, April and May are our snowiest and wettest months.”

Elder said it takes patience to see how the snowpack develops. “We don’t want to make any decisions about our supply this early,” he said. “We’ve still got a ways to go this winter and even though we are above normal now, weather conditions can change quickly.”

Snowpack: Here today, gone tomorrow?

A recent study finds that climate change means less water from melting snow. So what are we doing about it?

By Kim Unger

snowpack measure winter park

Denver Water employees stationed in Winter Park take measurements of snowpack in 2014.

Denver Water’s extensive reservoir system helps us monitor water supplies, even as a new climate change study warns of a shrinking snowpack.

A recent study from the Earth Institute at Columbia University found that the snowpack in the Northern Hemisphere has a 67 percent risk of declining — greatly reducing the amount of drinking water available from that source.

The study focused on river basins that rely on snowpack and are not adequately replenished by rainwater. The study identified the Colorado River basin among those at high risk for greatly reduced snowpack in the future, when demand for water will outpace availability. The river provides water to seven states, including Colorado.

As worrisome as that sounds, the study doesn’t provide a complete picture of how climate change may affect Denver’s water supplies, said Laurna Kaatz, Denver Water’s climate adaptation program manager.

She isn’t raising any alarm bells.

“This study is a big picture look at how sensitive systems are to different conditions,” Kaatz said. “It’s not a deep examination into the full range of possible climate changes Colorado could experience in the future.” Nor does it dive into how water managers in Colorado are contending with those potential changes.

“We have to consider all of the local variables in our planning,” she said.

Those variables include population growth, how efficiently customers use water, environmental and ecosystem needs, and local climate and weather patterns.

Denver Water’s supply is mostly from snowpack. The snowpack — the total amount of ice and snow on the ground — fluctuates from year to year. In warm, dry years, it can be gone by mid-summer; in wet years it can last through the next winter season.

“Our region experiences huge fluctuations — or variability — in weather and climate conditions,” Kaatz said. “Fluctuations, especially in precipitation, mean that the rivers and streams that supply our water are also highly variable. This is why reservoirs are so important in Colorado. Colorado’s high peaks protect the snow for months out of the year, and our strong reservoir system protects our water supply against seasonal and annual variability.”

Making sure water is available when customers need it requires careful management of how water flows in and out of reservoirs. Kaatz explained, that when the snowpack melts, we capture what we need and store it for future use. In years of drought, reservoir levels go down, and customers need to be even more conscious of water use.

Denver Water works with the scientific community to stay up-to-date on the latest models and trends because we live in such a variable climate.

“As the climate continues to warm, we do anticipate that snowpack will not live as long into the summer and fall months, especially in warm, dry summer and fall seasons, and that variability will increase,” Kaatz said. “At Denver Water, we plan for the long-term and look at the many different challenges we could be up against in the future, including climate change.”

While the study gives a potential glimpse into our water future, the full story is really told in how well Coloradans have embraced water conservation. Per capita water use among Denver Water customers hit a 50-year low in May, a savings of 2 billion gallons compared to recent years.

%d bloggers like this: