Design for Dry Creek floodplain fix nearly done
By JoAn Bjarko
North Forty News
A fix for floodplain problems in north Fort Collins should get under way
in February, if state and federal agencies give their final blessing to
construction plans.
A year and a half ago, staff at Fort Collins Utilities decided to work
on reducing the risk of a Dry Creek flood with a project that could be
entirely funded with the city's stormwater fund. The city has allocated
$8.1 million for the project, to be spent over three years, according to
Jim Hibbard, engineering and field operations manager.
Originally Fort Collins and Larimer County were working together on a solution
estimated to cost more than $15 million, but the county was unable to continue
financial assistance.
The Dry Creek Basin encompasses about 62 square miles, with hundreds of
residential and commercial structures located in the floodplain. Dry Creek
enters Fort Collins near Willox Lane and College Avenue and meanders through
small remnants of ditches and channels until it joins the Cache la Poudre
River near Mulberry Street and Timberline Road. At this time, any businesses
in the floodplain that want to expand or renovate have to follow federal
standards for floodproofing, which is often cost-prohibitive.
The city's final plan revolves around two concepts - adding places to detain
more stormwater and releasing stormwater in a controlled fashion. Existing
reservoirs and ditches owned by irrigation companies are key components
to the city's plan. Negotiations are not yet complete.
"We hope to start construction in February if all agreements are in place,"
said project manager Dean Saye.
Following the flow of water from north to south, here is a summary of what
the city utilities department wants to accomplish.
Modify the existing spillway at Douglas Reservoir to better control floodwater
dumping into Dry Creek.
Build a large dry detention pond on property owned by the city of Thornton,
about three-quarters mile north of County Road 56 and east of CR 19. The
dam embankment would be 2,200 feet long and 22 feet high. Water could cover
95 acres in a 100-year rainfall event (a storm that has a 1 percent chance
of occurring in any given year).
Build a 10-acre detention pond south of CR 56 and east of CR 19 at the
confluence of Dry Creek and Little Dry Creek.
Build remote-control operated gates on the Larimer and Weld Canal, about
a half-mile west of Shields Street and Willow Lane.
"By the time water gets to College and Willox, it's slowed the water down
enough so there's room in the Larimer and Weld Canal," Hibbard said.
Build a grass-lined diversion ditch at the east end of Lindenmeier Lake
to carry water into Dry Creek at Vine Drive.
Without the flood control project, Hibbard explained, water could rush
through North College and the Airpark at 6,000 cubic feet per second. With
the improvements, the flow will be cut to 700 CFS.
The city is still working with private landowners on a way to get water
from the area south of Vine into the Poudre River. Even if that section
is delayed, properties farther north and east will still benefit from the
project, Hibbard said.
Hibbard and Saye are hopeful that construction can be completed within
a year. It could take another year for the Federal Emergency Management
Agency to approve new maps showing what properties are no longer in the
floodplain.
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