Ask Eartha: I’m a kayaker. How will climate change affect our local rivers?

 In Ask Eartha

Dear Eartha, I know that climate change will impact ski seasons, but I’m a kayaker, too. How will climate change affect our local rivers? -Tom, Frisco

As summer draws to a close and we start packing our aquatic toys for the season, it’s an excellent time to reflect on how important our waterways are. Whether you’re a kayaker, rafter, SUPer, fisher, Lake Dillon beach-goer, or – heck – just a human, water is essential to our well-being. Unfortunately, climate change poses a serious threat to our water availability.

The Mighty Colorado

One of the West’s mightiest rivers – the Colorado – is right in Summit County’s backyard. Over the course of its 1,450 mile length, its waters serve over 40 million people and irrigate 15 percent of US agricultural products. Vegetables in wintertime? Lush golf courses in the desert? Thank the Colorado River.

Since 2000, however, the Colorado has been in an extended drought. In fact, data from tree rings indicate that this is the most extreme drought our region has experienced in the past 1,250 years. On average, annual flows are down more than 16 percent. Water levels in the nation’s two largest reservoirs, Lakes Mead and Powell, are at all-time lows. Only a year ago, the summer of 2018 was the warmest and driest on record in the Colorado River Basin going all the way back to 1895. Why? Scientists have linked the decline in flows to higher temperatures from our rapidly changing climate.

The Ripple Effect of Warmer Temperatures

Warmer temperatures affect water supply in a few different ways. First, as temperatures increase, more wintertime precipitation falls as rain instead of snow. In the Upper Colorado watershed (where we live), 73 percent of winter precipitation currently falls as snow. Under a high emissions scenario (that is, if we do nothing to fight climate change), by 2065 only 43 percent of winter precipitation could fall as snow.

A higher rain to snow ratio is problematic, not only for a high-quality ski season. Snowpack serves as a frozen reservoir – it’s our water stores for the summer. As the snow gradually melts, we receive a relatively continuous supply of water in streams and rivers. Think about how full Lake Dillon gets every spring as the snow starts to melt. But unlike snow, rain runs off instantaneously, leading to decreased summertime flows. In 2018, raft companies across the Colorado River Basin had to cut their seasons short because flows in the river were too low.

Higher temperatures also affect evaporation. How? Warm air is thirsty; it holds more moisture than cooler air. As temperatures increase, more water vapor will be absorbed from the soil, plants (including crops), and waterways. Again, this has multiple consequences. With respect to agriculture, drier soil and crops will require increased irrigation, pulling more water from rivers. But lakes, streams, and rivers will have less water available simply because of increased evaporation. One study found that for every 1 degree Fahrenheit increase in temperature, the flow of the Colorado River declines by 4 percent. And keep in mind, declined flows also lead to increases in water temperature, putting stress on fish and other aquatic life – not to mention the wildlife that feeds on the fish.

Average temperatures across the state have already increased 2 degrees Fahrenheit in the last 30 years. Depending on what the global community does to limit future emissions, we could see an additional 6.5 degrees warming here in Colorado by 2050. That would mean the flow of the Colorado River could decline by over 25 percent! That scenario does not bode well for future river floats.

Tapped Out

If climate change weren’t bad enough, the Colorado River is tapped. The Colorado River Compact, created in 1922, allocated the rivers water among the seven basin states and Mexico. But the Compact promises more water than actually exists in the river. An increasing population requires even more water to survive, but there simply isn’t enough to go around.

Frankly, the river is at risk. If you’re interested in learning more about the future of the Colorado River, join High Country Conservation Center on September 18 from 6 – 7:30 PM at the Frisco Adventure Park Day Lodge for a talk by Brad Udall, the senior water and climate research scientist at the Colorado Water Institute. Udall will discuss the past, present, and future of the Colorado River in a changing climate. The talk is free to attend, and light refreshments will be provided.

It’s not fun to contemplate a future with less water – let alone less river play. For those of us outdoor recreationists, it’s time to start paying attention to how climate change will impact our favorite pastimes and start rallying for action. Thanks for thinking about the river, Tom, and I hope to see you at the event!

Ask Eartha Steward is written by the staff at the High Country Conservation Center, a nonprofit dedicated to waste reduction and resource conservation. Submit questions to Eartha at info@staging.highcountryconservation.org.

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