The Hartford Metropolitan District Commission (MDC) sought a complete separation of sanitary and storm sewer systems in the Franklin Avenue area. Although necessary to achieve regulatory compliance, the project had multiple additional objectives, including elimination of backups into residences, reduced street flooding, and reduced overflows to the Connecticut River.
Streets in the area contain densely concentrated but poorly documented utilities. The complex sub-surface conditions demanded thoroughly inspecting and carefully planning details of both design and construction. To eliminate private inflow sources, the design needed to include disconnecting approximately 1,180 private properties, with inspections and design occurring on a very short schedule. The project team had to coordinate the design and execution of this project with an adjacent project pursuing similar goals, as well as plan construction sequencing and hydraulic elements to account for downstream projects.
The project team conducted intensive combined surface and sub-surface investigations, including manhole and catch basin inspections, Closed Circuit Television pipe inspection, field surveys, geotechnical borings, environmental sampling, utility company research, and house-to-house inspections. To clarify sub-surface utility locations, the team used pipe locators, ground-penetrating radar, and vacuum excavation. The team performed a hydraulic model of the collection system and analysis of the existing catch basins. Kleinfelder is also evaluating green stormwater strategies, such as rain gardens, green roofs, and grass swales, as components of the project.
This cost-effective sewer separation removes the threat of backups and floods, while meeting the federal Clean Water Act requirements and minimizing disruptions to local residents and business owners.