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City of Danville sewer
Project Summary
Hanson provided engineering and construction services for improvements to the Northwest Sanitary Sewer Service Area in Danville, Illinois. The project included restructuring the sewer flows in the area to improve efficiency and better reflect residential growth. The sewer infrastructure serves five subdivisions, nearly 400 additional residential units in the vicinity of the Danville Country Club golf course and 685 acres of future development.
The sewer infrastructure on the west side of Lake Vermillion was aging, and the original design of the collection system had assumed a different growth pattern than what occurred in the area. The city of Danville hired Hanson to confirm the recommendation of an initial feasibility study that evaluated how best to reconfigure the flows and proceed with the system’s design. Hanson also worked with the city to expand the project into a roadway improvement, adding a multiuse path on the causeway over Lake Vermillion to provide access and connect the two sides of the lake.
As part of the updates, Hanson reconfigured the sanitary flows to eliminate one of four lift stations, installed new gravity sewers and force mains and upgraded lift stations for future flows.
The improvements required changing the area’s flow pattern by reversing the direction of a trunk sewer’s flow. The rerouted gravity sewer consisted of approximately 1,250 feet of 15-inch sewer and 2,850 feet of 18-inch sewer, of which 378 feet was suspended over Lake Vermillion.
The project also included a roadway improvement plan with bicycle and pedestrian accommodations and upgraded roadway lighting on Denmark Road between Old Ottawa Road and Logan Avenue. Hanson performed an intersection alternatives analysis for the intersection of Winter and Logan avenues with Denmark Road. Final roadway plans included milling and overlaying the roadway, as well as adding curb and gutter along the project corridor, with bicycle and pedestrian accommodations on Denmark Road between Old Ottawa Road and Logan Avenue.
Hanson faced multiple challenges during project design and construction. Coordinating multiple funding sources from different agencies required significant communication and specific project staging. Another key obstacle was sandy soil on the hill leading up the west side of Lake Vermillion. Because of soil instability, the project team added continuous shoring to allow the gravity sewer’s installation.