A Phase 1 Stream Geomorphic Assessment following Agency of Natural Resources Protocols was completed for the West Branch Little River watershed by Lamoille County Planning Commission (LCPC) during summer 2005. During Phase 1, the West Branch watershed was divided into 72 reaches, encompassing roughly 47 miles of river channel. In the fall of 2005, a Phase 2 Stream Geomorphic Assessment following Agency of Natural Resources Protocols was completed for the lower portion of the West Branch (downstream of the Ranch Brook confluence) by Bear Creek Environmental (BCE). A Phase 2 assessment was completed for the upper portion of the West Branch in 2008; approximately 7 miles of river were assessed. Bridge and culvert data collected by BCE during the Phase 2 assessment were used to identify structures that have the potential to fail because of channel adjustments, are having a geomorphic impact on the stream, or are impeding aquatic organism passage. Stream geomorphic and habitat data collected during 2005 and 2008 were used to develop the corridor plan for the upper West Branch watershed.
The West Branch has a watershed size of 27.7 square miles. The Phase 2 study focused on stream reaches on the main stem of the West Branch upstream of the Ranch Brook confluence, and the lowest stream reaches on Pinnacle Brook, Inn Brook, Big Spruce Brook, and Long Trail Tributary. The combined length of the stream reaches assessed is 6.7 miles. The West Branch begins on Mt Mansfield and flows southeast towards the Little River, which then enters the Winooski River at approximately 390 feet above sea level and drains westerly into Lake Champlain. The West Branch watershed flows through three towns (Cambridge, Underhill, and Stowe). The West Branch watershed falls under the jurisdiction of the LCPC and the Chittenden County Regional Planning Commission. This project focused on only those reaches within Lamoille County.
The major problems in the upper West Branch watershed include channel straightening associated with the construction of roads and development. Alteration of stream channels has caused major to extreme channel degradation resulting in sediment build up, channel widening and planform adjustment. Many of the small streams, such as Inn Brook, have undersized stream crossing that are causing localized geomorphic instability and are impeding aquatic organism passage. High quality streamside buffers are lacking along Inn Brook and some areas of the West Branch and Big Spruce Brook. Generally the West Branch above the Ranch Brook confluence and Pinnacle Brook have high quality forested buffers that are worthy of conservation.
As the river works toward a more stable equilibrium, the community of Stowe has the opportunity to provide long-term protection to the river corridor and encourage the reestablishment of floodplain vegetation and healthy instream habitat. At the reach and site level, potential restoration and protection projects that would be compatible with geomorphic adjustments and managing the stream toward equilibrium conditions were identified. A list of 23 potential restoration and conservation projects was developed during project identification. Types of projects include: river corridor protection through corridor easements and conservation efforts, replacing undersized structures causing localized channel instability, improving riparian buffers, and arresting active channel incision.
The management plan and maps appear below with various file size options for download. All files are in Adobe Reader pdf format.