Federal, state and city engineers embarked on an overhaul of metro Denver waterways Wednesday, launching a $3 million feasibility study, aiming to replace cement-lined corridors with wider, flood-resistant natural creeks.
This shift would harness stormwater by slowing it in gulches, to be filtered naturally and irrigate native plants — instead of funneling it directly into the South Platte River.
“We have a lot of opportunities to restore our ecosystems to a natural state. Definitely, the Platte River we can deepen. We can work with edges of the river. We can use native species,” Denver public works director Jose Cornejo said.
“And in our drainage basins we can go from closed-pipe systems to open channels,” Cornejo said. “Our tendency will be to use natural channels and to use stormwater in a different way. When you pipe it, you’re not using it — you’re just taking it to the river with all the contaminants.”
Denver’s emerging effort mirrors similar projects with the U.S. Army Corps of Engineers in other cities, such as Los Angeles, to rip out heavy cement structures of last century and restore natural systems.
It jibes with Denver need to update flood-risk assessments for neighborhoods in the face of projected climate calamities. Ruinous flooding along Colorado’s Front Range in 2013 has piqued city concerns about safety and resilience.
But such an overhaul of all gulches, drainage areas and rivers could cost hundreds of millions and be years in the making — depending on land acquisitions, cooperation with neighbors and how much funding the Army Corps can provide.
The engineers on Wednesday began a jointly funded $3 million study by holding the first of three public forums in Sun Valley, Denver’s lowest-income neighborhood. It sits at a risky area where Weir Gulch waters trickle, and sometimes gush, near ailing public housing inhabited by refugees.
Engineers said they want to hear as much as possible from residents.
They’ve enlisted Somali, Spanish and Vietnamese interpreters. Flash floods in 2007 swept away a toddler who was with his mother and another toddler drowned last year. But residents who live in the area and grew up there said Wednesday they would prioritize having more natural green space with trails along water.
South Platte River Foundation director Jeff Shoemaker said he is “absolutely convinced something real is going to come of this. But it is going to be more of a marathon than a sprint.”
It’s been nearly . Colorado responded with massive cement flood control projects to guard against periodic surges.
But water experts from the Environmental Protection Agency to the Army Corps increasingly see both environmental and flood control benefits in letting waterways be natural.
Denver senior engineer Selena Klosowski said less cement, where feasible, would favor creation of an urban riparian oasis giving great opportunities for bike-riding — not to mention safety.
“What happens with a natural river is that it auto-corrects itself. When a large rainstorm happens, the river naturally adds curves to slow down the water. That self-correcting ability is desirable. It is resilient and more sustainable. Along with going to that curving natural pattern, using native grasses and shrubs allows it to grow. What we’re trying to do is get back to that,” Klosowski said.
“This study will identify the most cost-effective ways to achieve these goals.”
Bruce Finley: 303-954-1700, bfinley@denverpost.com or twitter.com/finleybruce
