From The Colorado Springs Independent (Pam Zubeck):
The city’s stormwater measure on the Nov. 7 ballot has stirred a lot of debate. Some don’t like the flat-fee concept — $5 per household, and $30 per acre for commercial land. Others say too many details remain unresolved.
But one thing is beyond dispute: Colorado Springs’ stormwater system sucks, and it’s going to take many years and a lot of dough to fix it. Far from a sexy topic, stormwater drainage gets no respect, and the consequences of that came into full focus during a tag-along with Water Resources Engineering Division Manager Rich Mulledy on Aug. 31.
To grasp the gravity of the problem, you have to get down in the weeds, literally, to see what’s going on along channels that border roads where tens of thousands of cars whiz by daily, their drivers unaware of possible catastrophes waiting to happen.
Mulledy, a slim 38-year-old engineer and Colorado Springs native sporting a Chicago Cubs cap, leads the way on a short hike behind the Goose Gossage Youth Sports Complex on Mark Dabling Boulevard. “So if you’re playing ball out here,” he quips, “you wouldn’t know about it.”
Beyond the outfield fences, he passes through trees before scampering down a steep embankment to a sandbar where Monument Creek gurgles its way along an embankment prone to sloughing, which sends sand, gravel and trash careening down the creek to its confluence with Fountain Creek, which, in turn, flows south to the Arkansas River east of Pueblo.
Fountain Creek, Mulledy says, is unlike any other in the United States due to its wild fluctuations in flows, from 125 cubic feet per second during normal times to 25,000 cfs in heavy storms. “There’s no other creek that’s a sand bottom creek that sees that kind of flash,” Mulledy says. “It’s a tough creek.”
Rushing runoff from Colorado Springs crumbles banks and sends hundreds of thousands of tons of sediment to Pueblo County, whose officials are none too pleased. There, sediment clogs levees and befouls the Arkansas River. After a 2014 regional ballot measure to fund drainage projects failed at the polls, Pueblo County officials threatened to rescind their construction permit for Colorado Springs’ Southern Delivery System (SDS) pipeline that delivers water from Pueblo Reservoir, unless the city dealt with stormwater. A deal approved by City Council in April 2016 enabled SDS’s activation in exchange for the city spending $460 million on drainage over the next 20 years. That spending eats into the general fund budget, which Mayor John Suthers says is needed to hire more cops and firefighters. Hence, the stormwater fee measure, which is intended to lift that burden.
On this August day, Mulledy doesn’t have to point out damage from Monument Creek’s raging waters. A 20- to 25-foot dirt wall towers along the east side of the creek, where waters carve the banks and threaten to undermine the wall, triggering a collapse of a plateau above. That could bring a storage business crashing down.
“The natural tendency of a stream is to move,” Mulledy explains. “Point [sand] bars move and push the water into the bank. It’s a built environment, so we built up next to it. Now, there’s nowhere for the river to move.”
The city plans to install grouted boulders along a 350-foot stretch at the base of the wall, tying into bedrock. Then, the area will be backfilled with dirt to create a slope, which will be sown with seed to encourage vegetation. “Then it can hold itself, even in big storms,” he says.
Sounds simple, but getting the right kind of heavy equipment into the creek area poses a challenge. “With road work, you can drive up, mill it and pave it,” Mulledy says. “Here, we have to create an access point. We have to bring material in, then we have to armor it for a 100-year [flood] event.” Moreover, the stream’s path itself will need to be moved west to allow workers to construct the project. Lastly, drop structures will be built to flatten the creek bed and retard the water’s flow.
After the project is completed in 2020, Mulledy says, the site should be inspected annually to assure it holds.
North Douglas Creek
As cars speed by on Interstate 25 just yards away, Mulledy hikes down a slope, through sunflowers and thistle, to the edge of North Douglas Creek where he warns visitors to stay away from the edge — a drop of 30 feet to the creek bed.
Here, the creek has eroded soils so dramatically that part of a concrete box culvert has broken off and been carried about 20 yards downstream. Gas and water lines are exposed, along with a drainage pipe, which juts some 10 feet from the canyon wall, acting as a yardstick for how far the banks have been chipped away.
“Colorado Springs Utilities is worried about that gas line and so are we,” Mulledy says.
To the north is Johnson Storage and Moving, while on the south side lies a construction materials business. Both are threatened.
“Johnson Storage is losing their lot,” Mulledy says, noting the embankment is chipping off several feet per year. Erosion is so bad, Sinton Road adjacent to the culvert could topple some day.
One of the problems stems from development practices in the 1960s and ’70s that followed the then-conventional wisdom to simply move storm flows out of the city as fast as possible. Now, best management practices call for slowing down those flows using detention ponds and drop structures. “We have a better understanding than we used to,” Mulledy says.
This segment of Douglas Creek is part of the city’s network of 270 miles of open channels and 500 miles of storm sewers — subject to inspection by federal regulators of the city’s municipal separate storm sewer system, or MS4, permit, issued through the Environmental Protection Agency.
Violations of that permit and the Clean Water Act led the EPA and the state to sue the city last year. The case is pending and could take years to resolve as the city reconstitutes its program to address water quality and conveyance, compliance with plan review and site inspection for new developments, and maintenance of its entire system.
This particular spot is so tenuous that Mulledy says crews visit it whenever heavy rains come. The fix, he says, will require installation of concrete walls along the bend in the creek to stop sloughing earth, structural fill and grouted rock. A crane will be employed to remove chunks of the concrete culvert.
Cost: $3.5 million.
Like many other projects, this undertaking will require the approval of federal flood plain managers and the Army Corps of Engineers. Work is slated for 2020.
The most spectacular sight of the day comes at a canyon just north of the Margarita at Pine Creek restaurant, which sits dangerously close to a roughly 50-foot drop-off to Pine Creek below. Another on the city’s list of 71 projects included in the intergovernmental agreement with Pueblo, this site will require stacking boulders to create a wall at least 10 feet high, from the creek bed to the bottom of an exposed limestone shear. Below that limestone is a clay layer notoriously susceptible to erosion. Under that lies pure shale, easily crumbled, especially when the creek runs up to 10 feet deep during 10-year storms. “It’s a little stream,” Mulledy says, “until it rains.”
The project was specifically identified by Pueblo County due to the large amounts of sediment washing into the creek and on to Pueblo via Fountain Creek. Pine Creek starts in Black Forest, winds through Falcon Estates and finally barrels through this canyon before it meets with Monument Creek about a quarter mile away. Power lines along the ridge top are mere feet from the canyon’s lip, and about 100 yards upstream, a bridge might be in danger eventually, Mulledy says.
Like the others, this site will be challenging to access, driving the cost up, he adds.
Cost: $2 million.
The project will be designed next year, and construction is due to begin in 2019.
Green Crest Channel
Green Crest Channel almost claimed a couple of businesses and a portion of Austin Bluffs Parkway back in 2010 before the city shored up the dissolving embankment with a project completed in 2015.
Mulledy worked on the solution to the problem while he was an engineer with Matrix Design Group, later joining the city in February 2016. By buttressing the banks and installing drop structures and grouted boulders, the stream is now healthy and lined with vegetation, such as willows, that appears historic but was placed there by Matrix as part of the project.
Because the new features, including four drop structures, slow the stream’s flow in Templeton Gap, erosion is dramatically curtailed downstream.
Cost: $2.8 million.
Another project upstream from Green Crest will further secure the waterway. At Siferd Street in Park Vista, just east of Academy Boulevard, even a small rain creates monster flooding from an over-topped Templeton Gap waterway. Plans call for crews to raise the road by several feet, lower the creek, and install a box culvert and five drop structures downstream. Work begins in 2020.
Cost: $3.75 million.
Those projects just scratch the surface of problems that become evident when face-to-face with the city’s stream system. With the price tag in the high millions, Mulledy notes he wants to maximize those dollars. That’s why his staff works hand-in-glove with Utilities and the Parks Department to find opportunities to incorporate trails and recreation facilities where plausible.
“Most of our projects are on green corridors,” he says, “so we look for opportunities for green spaces.”