Project Details

Project Name

Project Location

Project Description

The second phase of a multi-agency effort to restore Lower Colgan Creek was completed in 2022 with Green Valley providing CM and inspection services.

The GVCE team oversaw the restoration of an inhospitable concrete flood control channel constructed in the 1950s to a living, breathing creek that now offers recreational opportunities and improved habitat for aquatic life. The 3-Phase restoration project will accomplish a long-time goal of restoring the Creek from Bellevue Ave. to Victoria Dr. The original Creek geometrics has been for flood control and resulted in minimal tree canopy, which caused elevated creek temperatures and an environment that supported the spread of invasive plants with no support for fish and native wildlife.

Phase 2 restored over 1.3 miles of the creek channel, with improvements including the addition of channel sinuosity, re-grading of the cross-section for a natural geometry, installation of a series of pools and riffles to benefit the migration fish and fowl, installing numerous sizeable woody debris habitat structures, extensive plantings of native vegetation and construction of a paved bicycle and pedestrian path at the top of the banks to allow for safe passage through the Creek – a vast improvement in an area of the City that does not have sidewalks.

A large-scale grading operation undertaken during a strict schedule to comply with permits requirements and tightly monitored by permitting agencies and an on-site biologist, the Creek’s protection increased from a 25-year flood to a 100-year flood, with increased groundwater infiltration to recharge basins.  Both improvements drastically needed for drought relief and the reduction of flood risks to the community.

The Creek flow had to be bypassed around the project site allowing excavation and realignment of the creek channel to occur. Dewatering the site was required throughout the project to ensure a dry work site. Restoration of the site included installing boulders, erosion control fabric, over 1,000 native plants, and an irrigation system.