Colgan Creek Restoration Phases

Phase 1 – Design 

The conceptual design for the Lower Colgan Creek Restoration Project presents a vision of restoring Colgan Creek between Victoria Drive and Bellevue Avenue in Southwest Santa Rosa. Lower Colgan Creek has been straightened for ease of flood control and has very little canopy cover, leading to elevated creek temperature and a habitat that supports the spread of invasive plants like Himalayan blackberry and wild teasel. The restoration will increase flood holding capacity, water quality and habitat value of the creek by increasing the stream width, adding meanders and installing native plants to bring back a healthy riparian forest. In addition, the project will provide a safe route from the local neighborhood to school, in an area that does not currently have sidewalks in all neighborhoods.This project is phase one of three. Each phase is defined by creek reach.  Phase One will restore 2,255 lineal feet of the creek and install at least 1,000 native trees and shrubs adjacent to Bellevue Avenue starting at Dutton Meadow and ending in front of Elsie Allen High School.  This section is an important section to start with, because it will provide the first part of a trail connecting the school to the local neighborhood.

Santa Rosa officials show off rehabilitated Colgan Creek >

Phase 2 – Construction

Remove and relocate existing storm drain outfalls to new channel locations. Existing storm drains and their outfalls will be modified to work with the new channel geometry. This includes relocating and modifying storm drain inlets to work with the revised grading. Existing storm drain pipes will be removed during grading operations and then constructed to work with the new channel geometry. These storm drain pipes will be lengthened in some cases and shortened in others.

Phase 3 – Restoration

Tasks as listed in the budget and project description that allow for relocating the creek channel to create a more natural channel with meanders, flood plains and enhancement of habitat and native riparian planting. The timing and sequence of construction will be finalized after the contract is awarded and the project schedule is approved from the contractor.

In order to construct the project the existing vegetation and access road need to be removed.  Flow within the creek needs to be bypassed around the project site in order for the excavation and realignment of the creek channel to occur.  Dewatering of the site is required throughout the project to ensure a dry work site.  Restoration of the site will include installation of boulders, boulder weirs, erosion control fabric, over 1,000 native riparian plantings and an irrigation system.  Once installed, the plantings will be maintained to ensure 80% survival after the three year plant establishment period.

Phase 4 – Path:  Install a 10 foot wide paved pedestrian/bike path and pedestrian flasher at Bellevue Avenue Crossing by Elsie Allen High School, lighting and trash receptacles.