Location: Jay, VT
Application: Water Quality – Debris & Sediment Removal
Product Used: SiteSaver STSS-4
Water Quality Flow: 3.11 CFS
Peak Flow: 24.90 CFS
Sedimentation Requirements: 80% TSS – OK-110
Owner: Jay Peak Resort
Installing Contractor: Dale E. Percy, Inc
Engineering Firm: VHB – South Burlington, VT
A SiteSaver stormwater treatment device was installed under the Route 242 parking lot at the Jay Peak Ski Resort, located in Jay, Vermont as part of the Resort’s Water Quality Remediation Plan.
The Route 242 parking lot, located at the intersection of Stateside Road and Route 242, was constructed prior to stormwater treatment regulations. Stormwater runoff from the site and adjacent developed areas has historically discharged to receiving waters without significant stormwater treatment. After monitoring the receiving water, Tributary 3 of South Mountain Branch, it was determined that the stream was not meeting the state’s water quality standards due to high sediment loads.
In accordance with the Water Quality Remediation Plan, the resort was required to implement a “large-scale BMP” in 2018 and selected to retrofit a stormwater treatment device under the parking lot with the objective of reducing the annual sediment loading to the stream. Andrew Mills, P.E. Project Manager at VHB, explained that surface solutions and infiltration practices were also evaluated for this project; however, space and natural resource constraints limited the area available for a surface solution, and infiltration was not practicable at this location due to the underlying soils classification (Cabot silt loam, hydrologic soil group “D”). Therefore, a subsurface, flow-thru system was determined to be the optimal device for the retrofit project.
SiteSaver, StormTrap’s unique hydrodynamic separator, was selected for this project for its ability to remove 80% Total Suspended Solids (TSS) from runoff while also preserving the existing land use. “The project constraints required a subsurface treatment system that had to be located within a limited footprint and with minimal head through the system. The SiteSaver met these criteria while also provided an internal high flow bypass and ease of maintenance,” affirmed the engineer.
The SiteSaver designed for this project was a STSS-4 unit, composed of a precast concrete structure that housed inclined plates and baffles to remove suspended sediment, and a netting device to capture trash and floating debris. The device is predicted to achieve greater than 80% TSS removal based upon the anticipated particle distribution of the sediment and the design water quality flow rate of 3.1 cfs. Because the system was placed online, an internal bypass was used to safely convey the 100-year flow rate of 25 cfs without causing previously captured sediment to become resuspended or scoured. According to calculations for the site under existing conditions, the treatment system is anticipated to capture 20,080 pounds of sediment annually that would have otherwise entered Tributary 3.
The system was installed in one day, and the engineer of record affirmed that it was a positive experience to work with StormTrap on this project. The StormTrap team “provided support throughout the project, from conceptual design and calculations to pricing as well as on-site installation support,” reported Mills.