Vermont Business Magazine In June, Stone Environmental accepted an Engineering Excellence Merit Award from the American Council of Engineering Companies of Vermont (ACEC-VT) for an innovative green stormwater infrastructure design and implementation project for the Oak Street drainage area in St. Johnsbury, Vermont. The project was completed in collaboration with lead engineers from Dufresne Group, with critical support from the Caledonia County Natural Resources Conservation District (CCNRCD) and the Town of St. Johnsbury. The Oak Street Neighborhood Project is the first in Vermont to combine neighborhood-scale green infrastructure with “gray” infrastructure to reduce combined sewer overflow events.
The Oak Street Neighborhood Project started as a traditional utility improvement, including water main replacement and new sewer and stormwater collection systems. During the design phase for this work, a Stormwater Master Plan was also being developed by CCNRCD and the Town of St. Johnsbury, with support from Stone Environmental and funding from the Vermont DEC Ecosystem Restoration grant program. Much of the residential neighborhood slated for utility improvements was also underlain by sandy soils. The presence of suitable soils, and the utility improvements already in design, made incorporation of green stormwater infrastructure (GSI) a high priority for all partners.
As final design of the water, sanitary sewer, and stormwater collection system improvements progressed, all partners collaborated to incorporate GSI into the project. Design and construction of the GSI was funded through a Vermont DEC Ecosystem Restoration grant secured by CCNRCD. The GSI improvements included bioretention swales sited in the green space along roadways.
The bioretention swales treat runoff from 7.5 acres, including over 2 acres of impervious rooftops, driveways, and roads. The 22 GSI practices provide 5,550 CF of storage and treatment capacity—almost 300% of the “first inch” Water Quality Treatment Standard on a project where water quality treatment was not required by the Vermont Stormwater Management Rule. Through CCNRCD’s and Stone’s work in securing grants and providing engineering support, the town was able to install GSI at no cost but great benefit by reducing stormwater runoff in the Oak Street drainage area.
The Engineering Excellence Awards, created to commemorate outstanding examples of engineering excellence in projects completed in Vermont, were awarded to recipients whose projects were substantially complete and ready for use between January 2017 and December 2018. Recipients were judged on their ability to meet or exceed client needs, new applications of existing techniques, originality, and/or innovation, social or economic benefit, complexity, and technical value to the profession.
Source: Stone Environmental