ACEC of VT 9th Annual Environmental Protection
Technical Workshop
The event will be held both in-person and remotely from 10 am to 4pm on Thursday September 26, 2024 at 40 IDX Drive, Building 200, Red Clover Conference Room, South Burlington, VT 05403.
Agenda:
1. 10 am Presentation #1
2. 11 am Presentation #2
3. 12-12:30 pm Lunch/Networking
4. 12:30-1:30 pm Roundtable
5. 1:30 -2:30 pm Presentation #3
6. 2:30-2:45 pm Break (15 min)
7. 2:45 -3:45 Presentation #4
Presentations:
1. Emergency Dam Repair, Snowshed Pond Dam, Killington Resort
Presenters: Matt Schley, PE, Fuss & O’Neil
Presentation Description: Fuss & O’Neill is working with Killington/Pico Ski Resort Partners, LLC (KPSRP) to assist with dam engineering, hydraulic analysis, geotechnical review, and scoping to support emergency dam repair on a significant hazard dam located at Killington Resort in Killington, Vermont. The dam was identified as an emergency repair situation by the Vermont Department of Environmental Conservation Office of Dam Safety (ODS) during a periodic inspection in April 2024 due to a leaking wastewater effluent force main that runs through the dam embankment. ODS issued a Dam Order requiring Killington to draw down the impoundment, develop an Emergency Action Plan, perform hydraulic adequacy and dam breach modeling, and develop corrective action for the force main to eliminate future risk of dam failure and impacts to downgradient residents and infrastructure.
The existing dam is a 28 foot high, 610 foot long earthen embankment dam originally constructed in 1970 as a water supply for snowmaking, fire protection, and golf course irrigation. The dam has been modified and improved multiple times over its history to increase the total pond storage which today sits at approximately 65 acre-feet at normal pond and 94 acre-feet at brim up. As noted in the Dam Order, the downstream side of the dam embankment exhibited soil saturation and sloughing as a result of a leaking wastewater force main which was due to be abandoned and replaced in August 2024, but was accelerated due to this emergency.
Fuss & O’Neill and their subcontractors performed a suite of services to assist KPSRP including the installation of groundwater monitoring wells, soil exploration via hand augering, video recording of existing toe drains, H&H analyses of hydraulic adequacy and dam breach, and H&H analyses of outlet culverts immediately downstream of the primary dam spillway. These analyses showed that the leak in the force main has been corrected and that the saturated area of the embankment is a groundwater collection point. The H&H analyses have shown that the dam may be hydraulically inadequate and that the dam may qualify as high hazard due to flood water elevations and velocities at the ski-in/ski-out condominiums immediately downstream.
2. Protection of the Built Environment: Vermont’s Historic Railroads
Presenters: Britta Tonn Director of Cultural Resources-Vermont, VHB
Presentation Description: With the Vermont's State-Owned Railroads study, VHB Vermont's Cultural Resources Group assisted VTrans in identifying historic rail-related properties which illustrate the history and importance of the railroad in Vermont from a historic, engineering, and/or architectural perspective. These identified historic resources would be protected as they would be subject to regulatory review on future railroad maintenance and upgrade projects. The presentation will discuss the innovative nature of this comprehensive railroad documentation project, which is the first of its kind to be completed in the nation.
In 2022-2024, VHB Preservation Planners researched, surveyed, documented, and evaluated the significance of 281 miles of state-owned rail lines. These included the Washington County Railroad (“WACR”) – Connecticut River Division (102.2 miles), the Green Mountain Railroad Corp. (“GMRC”) (50 miles); and the Vermont Railway (“VTR”) (139.8 miles). Preservation Planners worked with a GIS colleague to create a custom-designed data collection app and webmap that enabled the group to survey almost 800 resources on the railroad tracks and 71 rail-related buildings and structures. Through research, data analysis, and evaluation of railroad properties, VHB produced a report that includes the most comprehensive history of Vermont’s railroads to date and an accompanying webmap which presents the results of the survey in a dynamic and visually compelling manner. This innovative project is an example of how field survey, GIS technology, and a deep understanding of the state’s history can be synthesized to
support the protection of an important component of the state’s historic built environment.
3. Middlebury Resource Recovery Center: Converting High Strength Wastewater to Energy
Presenters: Jonathan Ashley, P.E. Senior Vice President DuBois & King, Inc.
Presentation Description: The Middlebury Industrial Park is home to several food and beverage manufacturers. Medium and high strength wastewater generated by the manufacturers is historically managed through a combination of pretreatment and trucking off-site to area farm digesters and manure pits. The Middlebury Resource Recovery Center was designed and constructed with a small footprint on a 0.9 acre site within the industrial park, to receive piped feedstock including cheese waste from a whey plant and distilling byproducts from a cidery in the industrial park, reducing off-site trucking of waste byproducts. The facility is also designed with a truck receiving facility to take brewery waste, byproducts from distilling and kombucha tea production from other manufacturers in the area. The heart of the process is an anaerobic digester that will convert the organics in food and beverage waste into biogas to generate 1,014 kW AC power on a 24/7 basis to be fed into the Green Mountain Power grid. The facility is equipped with a membrane bioreactor to treat approximately 80,000 gallons per day. The reduced wastewater loading will be a benefit to the Middlebury wastewater treatment plant. Solids byproduct from the anaerobic digester can be added to compost or be directly applied to fields by local farms growing corn and bean crops. The presentation will cover challenges, opportunities, benefits, and lessons learned from the multi-disciplinary design, permitting, and construction of the project.
4. Investigation of per- and polyfluoroalkyl substances (PFAS) at the Former Pownal Landfill
Presenter: Stephen Hilfiker, P.G. Project Manager Site Investigation & Remediation
VHB
Presentation Description: VHB has conducted extensive investigations at the Former Pownal Landfill to evaluate the nature and extent of impacts to soil, overburden groundwater, bedrock groundwater, and surface water. Multiple contaminants of concern (COC) were initially identified at the site in 2018, with per- and polyfluoroalkyl substances (PFAS) being the primary COC. Iterative Phase II Environmental Site Assessments (ESAs) have identified PFAS impacts to overburden and bedrock groundwater and surface water. Our presentation will provide an overview of these investigations that have included evaluation of contaminant migration pathways in complex, heterogeneous glacial deposits and bedrock geology, evaluation of PFAS impacts to private supply wells, and analysis of surface waters that may be sources/sinks for impacted overburden and bedrock groundwater. VHB will use the findings of these investigations to inform the development and implementation of a corrective action plan to protect groundwater and human
health.
Round Table Discussion - Act 76 Clean Water Service Provider Program
Dan Albrecht – Chittenden County Regional Planning Commission
Mike Winslow – Addison County Regional Planning Commission
Brian Voigt – Central Vermont Regional Planning Commission
Ethan Swift or Chris Rottler - Agency of Natural Resources
