LONGMONT, Colo. (CBS4) – Flood mitigation work continues at an area along the Front Range that was devastated by flooding in 2013. Crews have been installing a new drainage system at Heron Lake in Longmont.

That new system has been designed to keep floodwaters from heading into some Longmont neighborhoods. The project cost $925,000. Boulder County is chipping in some of its FEMA money to help with the bill.

Flooding at Heron Lake in 2013 (credit: CBS)

Flooding at Heron Lake in 2013 (credit: CBS)

When water from the St. Vrain River breached Airport Road in Longmont in September 2013, it flooded more than 400 homes on the west side of Longmont.

“This was an area that was unanticipated, unexpected,” said Public Works Manager Dale Rademacher.

It was unexpected because the neighborhoods that flooded were not in the floodplain.

“But we certainly learned the lesson through the flood, that the river is going to behave differently to the west of the city than it had historically,” said Rademacher.

(credit: CBS)

(credit: CBS)

Public works is tackling that issue with easements from landowners and farmers that allow the construction of the Heron Lake relief channel at the eastern end of Pella Crossing. The channel is designed to intercept flood water coming from the St. Vrain, with a similar path in 2013, and then redirect it a half mile south, downstream.

“It is a way to tame flood waters that are coming at us from the west that are out of control and to get them into a more controlled state,” said Rademacher.

He said the project takes a natural approach. The channel will be lined with grass, “You can do flood control in a manner that also respects the environment around you.”

The project is meant to ensure future flood waters will bypass homeowners on their way back to the St. Vrain. It should be complete by November.


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