Bozeman Creek Water Intake Infrastructure Improvement FWP-DN-FSH-R3-24-079

Nov 19, 2024 3:23 PM

The project goal is to upgrade to existing water intake structure at Sourdough/Bozeman Creekl, which serves as the City of Bozeman water supply. Proposed construction activities at the site will include the installation of an infiltration intake to be used as the primary raw water intake, with the existing surface intake being retained as a backup system. The new intake system will collect stream water in 6, 18” diameter well screens placed about 4- 5’ under the existing streambed. Water lines and associated air backwash piping for maintenance will connect the well screens to a valve vault located outside the impacted area. The streambed will be excavated and lined with geotextile separation fabric, backfilled with washed rock, and covered with gabions. The existing stream will be reshaped from a wide, shallow pool into a narrower baseflow channel with overbank areas. The existing surface intake and spillway structures will remain undisturbed. A combination air valve will be installed at the high point in the existing water transmission main pipeline located on the western side of Sourdough/Bozeman Creek.

The water transmission pipeline is buried under the Sourdough Creek streambed and crosses the drainage where the valve will be installed. Installation of the valve will involve crossing the stream to access the high point, pot-holing (excavating) to expose the top of the pipe, and installing a tapping tee valve and access manhole. The stream in the vicinity of the intake is characterized by a wide, shallow pool behind a small dam with much of the eastern stream bank containing riprap and concrete. Wetlands were delineated within the project area. Upland vegetation consisted of large leaf avens, smooth brome, Canada thistle, dandelion, and rocky mountain maple. Wetland vegetation consisted of Nebraska sedge, tufted hairgrass, horsetail, mint, reed canary grass and fireweed.

The applicant is Bob Murray of the City of Bozeman. The project is expected to occur between 4/1/2025 and 10/30/2025.