The Niver Creek Tributary M Improvement Project was produced to mitigate recently identified local flood risks.
Niver Creek Tributary M is two-mile long riverine system draining just over one square mile of developed land. In 1984, the Niver Creek Tributary M watershed experienced significant flooding. The area experienced flooding again in 2011, and this time the Huron Street culvert overtopped. As a follow-up to a study done in 2016, the Mile High Flood District completed a Flood Hazard Area Delineation (FHAD) for the entire Niver Creek basin. The FHAD identified 11 structures southeast of Thornton Parkway and Gale Boulevard in the “100-Year Floodplain”..
The Project has three key focal points: upstream surface flow capture, channel improvements, and safe use of a Huron Street pedestrian underpass.
At the upstream end of the Project, the undersized culvert at Thornton Parkway results in overland flows across Thornton Parkway and Gale Boulevard. Project improvements include additional inlets and storm sewer, and a lowering of the curb and sidewalk in the southeast corner to collect this water off the streets and direct it into the channel, away from the homes.
From Thornton Parkway to Huron Street, improvements are being made to the channel to increase capacity which will reduce water depth. The lower depth will thereby remove the floodplain from the adjacent residential structures. These channel improvements include several design strategies such as widening the channel and maintaining more resilient, flexible floodplain plant species.
The culvert improvement at Huron Street is primarily to remove flood overtopping at the street level. This will reduce the flood impact to the travelling public. Since roadway overtopping is a key risk, the design effort provides a culvert capacity and resistance to clogging that maintains a dry and passable roadway in the “100-year” storm. The culvert is large enough that it will include a pedestrian trail connection into the Niver Open Space.
The project is currently under construction and is expected to end late summer/early fall of 2022.
The project is being funded by Mile High Flood District and the City of Thornton. ICON Engineering, Inc. is the design engineer, Valerian LLC provided landscape architecture services, Naranjo is the Civil Constructor, and Habitat Management will be providing the landscape restoration.