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Lamoille County Planning Commission

 

Brewster River Corridor Plan

Fitzgerald Environmental Associates, LLC (FEA) was hired by LCPC in fall of 2012 to assist with a Phase 1 and Phase 2 stream geomorphic assessment and to develop a River Corridor Plan for the Brewster River. The Phase 1 study and a portion of the Phase 2 study were completed in 2012-2013 and summarized in a report delivered in March of 2013. The remaining Phase 2 assessments were conducted in 2014 and are described in the River Corridor Plan. The objectives of the Phase 2 SGA and River Corridor Plan are described below:

  1. Develop a basis for understanding the overall causes of channel instability and habitat degradation along the river corridors in the watershed;

  2. Collect the information needed to map fluvial erosion hazard zones in Cambridge;

  3. Develop a list of preliminary river restoration projects that can be further developed in the future to mitigate flood and erosion hazards; and

  4. Further develop project packets for three high priority projects to support future implementation.

The Brewster River watershed is located in the Lamoille River Basin in northwestern Vermont. The watershed has a drainage area of 19.8 square miles and outlets to the Lamoille River immediately east of the VT Route 108 river crossing. The watershed is primarily located within the Town of Cambridge and Village of Jeffersonville, with small areas of the headwaters in the Towns of Johnson, Morristown, and Stowe. The mainstem of Brewster River drains the northwestern face of Sterling Mountain and joins with a major tributary draining the north face of Mt Mansfield and the Smugglers' Notch ski area.

Many of the reaches in the Brewster River watershed are dynamic and highly erosive during flood events due to ongoing adjustments to their dimensions, patterns, and profiles. These adjustments are in response to impacts from historical sedimentation in valleys from early European settlement and deforestation that caused hillslope erosion, as well as modern day impacts from channel straightening, dredging, berming, and corridor encroachment associated with adjacent roads and development. Recent large runoff events such as the spring 2011 floods and Tropical Storm Irene have also triggered channel incision, widening/deposition, mass wasting of valley side slopes, inputs of woody debris to the channel, and redevelopment of floodplain access in some areas. Ongoing vertical and lateral channel migration is likely in the future for many reaches within the watershed. Given these predictions for future channel adjustments, the Plan makes recommendations for management of the River Corridor including a list of potential projects, watershed wide and site-specific, that can help restore the river to a more stable and healthy condition.

The communities of Cambridge and Jeffersonville have the opportunity to provide long-term protection to the river corridor and encourage the reestablishment of floodplain vegetation and healthy in-stream habitat, while also mitigating flood hazards. 28 potential restoration and conservation projects were identified. Types of projects include: river corridor protection through corridor easements and conservation efforts, replacing undersized structures causing localized channel instability, improving riparian buffers, as well as several stormwater infrastructure improvements.

The Brewster River Corridor Plan appears below for download.