Salt Ash Road, Plymouth, VT

Challenge

The Salt Ash Owners Association (SAOA), representing property owners at the Hawk Inn and Mountain Resort in Plymouth, VT, sought engineering services to evaluate its private roadway infrastructure following a major storm event that caused extensive damage. Multiple gravel and paved sections of roadway were impacted, requiring both immediate assessment and long-term planning. Three roadway segments experienced severe washouts ranging from 30 to 500 ft in length, up to 15 ft deep, and as wide as 30 ft, resulting in significant structural failures. The project required a comprehensive evaluation of existing conditions, exploration of repair and resiliency strategies, and a cost-benefit analysis for upgrading to a more durable roadway system.

Solution

Our team performed hand excavations, survey work, and visual observations to investigate the existing roadway network. Test pit explorations were conducted along approximately five miles of gravel roadway to observe and classify subsurface conditions. Findings were documented in an engineering report that included recommendations for roadway restoration, material specifications, compaction requirements, and drainage swale details necessary to restore the roadways to pre-storm conditions.

A hydrologic and hydraulic (H&H) analysis of stormwater conditions was completed to evaluate water flow patterns and identify potential drainage deficiencies using a selected design. This analysis informed the design of improved stormwater conveyance systems to mitigate future flooding, erosion, and related issues. In parallel, a schematic roadway design and drainage study evaluated existing roadway infrastructure and analyzed potential design alternatives, considering feasibility, constructability, and long-term resiliency. These findings were compiled into a Schematic Design Report summarizing site observations, analysis, and proposed strategies for roadway and drainage improvements. Additionally, MSK performs annual wastewater system inspections for the Salt Ash Owners Association to ensure compliance, identify maintenance needs early, and extend the life of the infrastructure.

Results

The Schematic Design Report guides SAOA's phased roadway maintenance program, prioritizing critical repairs and integrating stormwater improvements. This approach helps allocate resources efficiently while improving safety, resilience, and long-term performance.