It’s like adding insult to injury.
As if flooding on Fountain Creek weren’t bad enough, mountains of sand are stacking up north of Pueblo waiting to descend on the channel through the city.
Dealing with it will take cooperation from the north and decades to correct.
“It’s like a big anaconda eating an animal and moving it down,” said Ian Paton, part of the Wright Engineering team hired by Pueblo County commissioners to analyze the problem. Commissioners heard a status report on what will be an ongoing study on Friday.
The problem may be bigger than previously thought, Paton explained.
The net gain of sediment in Fountain Creek works out to about 370,000 tons a year between Fountain and Pueblo, causing the river to shift its flow in the channel as the increasing amount of material obstructs its path. It keeps piling up year after year as it eats away 20-foot cliffs.
And, it has become worse since 1980, when Colorado Springs started booming in population and major infusions of water from outside sources — Homestake, Blue River and the Fountain Valley Conduit — began putting more water into Fountain Creek.
Southern Delivery System, a 66-inch diameter pipeline from Pueblo Dam to Colorado Springs, could increase Fountain Creek flows 60-100 percent, while depleting the Arkansas River through Pueblo. Water quality will become an increasing concern as more sediment is churned up.
“Population is the driving factor,” said Andrew Earles, Wright’s top water resources engineer. “To have growth, you need water, and since the 1970s, you’ve been putting more and more water into Fountain Creek.”
Additional water has allowed more growth, and increased base flow threefold.
But the growth also has increased impervious surfaces — roofs, parking lots and streets — by 10 percent of the total watershed area upstream of Security, and caused base flows, high flows (the kind seen this spring) and big floods to become more intense at all times.
The Waldo Canyon and Black Forest fires of 2012 and 2013 have caused storms to generate up to 100 times the damage that would have occurred prior to Colorado Springs’ growth surge, Earles explained.
“We can’t turn back the clock. We can’t put it back to the way it was in the 1950s and ’60s,” Earles said. “We can put it in better shape for the future.”
A big part of that will be developing ways to deal with increased flows into Fountain Creek at the source.
That would include detention of floods, bank stabilization and control of tributaries in ways that reduce damage on the main stream.
Wright Engineers evaluated Colorado Springs and El Paso County estimates of 454 flood control projects that could cost $723 million to complete for their benefit to Pueblo County. About two-fifths of the projects totaling $537 million would reduce destruction to Pueblo.
Colorado Springs officials are proposing $19 million annually to bring stormwater control back to the level it was before its City Council abolished the stormwater enterprise in 2009.
“So far we agree with their list,” said engineer Wayne Lorenz.
Lorenz said a dam between Fountain and Pueblo is “worthy of consideration,” but cautioned that such a oneshot solution could fail.
“A dam is more of a treatment for a symptom rather than a cause,” Lorenz said. “We can’t put all our eggs in one basket with a dam because it might not happen.”
Commissioners are also concerned that projects be maintained.
In Pueblo, the Fountain Creek levees are in need of repair in order to provide the same protection they were designed to give 25 years ago.
“The levee is badly silted and vegetated, and it would take $2 (million)-$ 5 million to bring it back to standards,” said Ken Wright, head of the engineering firm.
“The annual maintenance of the levee has been neglected.”
The fear is new projects on Fountain Creek could sink in the same boat.
“We need to make sure we’re not just building projects, but have the money to maintain them,” said Pueblo County Commissioner Terry Hart.