Department of Public Works

2013 College Street StormwaterShed Retrofits Green Infrastructure Plan

2013 College Street StormwaterShed Retrofits Green Infrastructure Plan

While much of Downtown Burlington drains to the combined sewer system (which discharges to the Main Wastewater Treatment Plant near Perkins Pier), a small 22.7 acre watershed is served by a separate stormwater collection system which discharges directly to Lake Champlain at the foot of College Street.  Samples taken from the collection system have shown high levels of sediment, phosphorus and other pollutants typical of urban stormwater runoff.  Various end of pipe grey stormwater solutions have been proposed over the years, but none have been implemented due to cost and lack of overall effectiveness of end of pipe solutions.  Additionally, these grey infrastructure elements would do nothing to add to the overall streetscape of this important corridor between Church Street and the Waterfront.

With the help of a $35K grant from the State of Vermont - Agency of Natural Resources, Department of Environmental Conservation, the City has worked with a consultant team led by Watershed Consulting Associates to develop a Green Stormwater Infrastructure Plan which identifies the retrofit opportunities throughout the watershed.  To date, the project team has successfully updated mapping and subwatershed delineations for the area, evaluated soils for infiltration, developed a green infrastructure toolbox and generated a comprehensive plan for all of the possible retrofit opportunities.  These retrofit opportunities were ranked and a final selection of high priority (based on water quality and other co-benefit cost effectiveness) "focus" practices were selected.  Work completed to date is available via this memo.

As part of the grant scope of work, conceptual engineering plans have been developed for the first two "collections" of green stormwater infrastructure practices - the Bank/Pine Streetscape and the College/Pine intersection.  Additionally, cost estimates for these practices and Stage 2 practices were developed.  (See Technical Memo).

For the final stages of this project, conceptual plans will be completed for the remaining high priority areas. All of the practices will also be depicted through drawings by a landscape architect to capture the impact of these practices on enhancing the street.  The final phase of the plan is scheduled for delivery mid February.  Modeling of the full build out scenario shows a 50% decrease in the Phpsphorus loading from the Water Quality storm (0.9" storm) and include additional reductions in sediment.

The Burlington Stormwater Program will be seeking funding from various sources to begin implementation of the practices as soon as possible.  

Final Conceptual Engineering Plans

Landscape Architect Renderings