Snowpack: Here today, gone tomorrow?
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.