The bounty of high-country snows that built up over Colorado’s long winter and cool spring is now starting to melt and flow down the state’s creeks, streams and rivers.
And as it flows into the rivers that feed Denver Water’s reservoirs, the utility’s planners are keeping a close watch on the volume of water that’s already in the reservoirs, the demand that’s needed on a daily basis by the 1.4 million people who rely on the utility for clean, safe drinking water, and the amount of water expected to head down the river.
Sometimes, those calculations result in the decision to let some of the water go — to spill it through areas of the dam engineered for just this purpose. Denver Water expects all the reservoirs in its system to fill this year.
And it doesn’t happen every year, but this year a few of the dams in Denver Water’s system are expected to spill for a few days or weeks.
It’s a mesmerizing, awe-inspiring sight, and a reminder of the grace and power that resides in nature.
At Strontia Springs Dam, 6.5 miles upstream of the mouth of Waterton Canyon on the South Platte River, the spillway was roaring during the last half of June. Thousands of gallons per minute thundered through the opening, hit a lip and arched into the air, only to crash on the rock-lined stream more than 200 feet below.
At the base of the dam, mist hovered in the air, lit with rainbows when the sun’s rays hit it.
The sights and sounds are gifts from Mother Nature that don’t come every year.
The last time Strontia Springs was able to spill was in 2015. Cheesman and Williams Fork dams last spilled in 2017.
“This year was the best snowpack in the last 20 years because it’s melting so late, stuck around so long and kept accumulating late in the season — when it typically starts melting,” said Nathan Elder, Denver Water’s manager of supply.
“Along with what’s happening in the mountains, this spring also had unusually low temperatures in Denver, meaning that so far the demand for water has been below normal,” he said.