Lopsided dry weather pattern prompts operational changes
People are talking about the dry winter across the state and what that may mean for this summer’s water supply. But, believe it or not, the weather isn’t the only thing Denver’s water managers are focusing on.
Lopsided snowfall across the state means our water managers are operating the system a bit differently to make the best use of water available.
That’s because Denver Water’s supply system is essentially separated into two parts: the North System, in which water from the Fraser River in Grand County and South Boulder Creek is stored in Gross and Ralston reservoirs, and the South System, which includes water from Dillon Reservoir and portions of the South Platte River basin.
Roughly 10 percent of the water in our collection system is stored in the north, and 90 percent is stored in the south. That’s a pretty big discrepancy.
And, the south part of Denver’s water system has fared much worse than the north this year.
This year, collection system data show we’ve had much more snow on the north – roughly 90 percent of average – than our larger basin on the south, which is at 70 percent of average.
"Because there will be more runoff in the north, and less storage available for it, we’ll start ramping up the Moffat Treatment Plant on the north side of our system, treating and delivering more water to customers from this location than we typically do," said Nathan Elder, interim manager of raw water supply for Denver Water.
“If we start using the water on the north end now, we can preserve water stored in the south and increase the likelihood of filling those reservoirs during this year’s runoff season,” Elder said.
But relying heavily on the north is not ideal, and one reason why the Gross Reservoir Expansion Project is so important.
“Our north system not only provides water to our north end but also works as a safety net for when problems arise on the south,”said Jeff Martin, program manager for Gross Reservoir Expansion. “The bigger the safety net, the less vulnerable we are to drought, forest fires, and infrastructure failures on the south.”
Expanding Gross Reservoir would allow Denver Water to store more water on the north, offsetting the current imbalance and giving us that bigger safety net.
“We want to preserve that small amount in the north just in case anything happens on the south,” Elder said. “If we have a better balance, we’re better prepared for those events.”