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Greensferry Sewer Tunnel

The Greensferry Sewer Separation project is being constructed to meet the obligations of federal consent decrees to eliminate combined sewer overflows (CSOs) in the City of Atlanta.  The project is a key component of the City’s CSO Remediation Program, and the approximately 60,000 lf of separated sewer includes a 1,200-ft long mined tunnel section.  Tunnel planning and design were complicated by the presence of a city park, two active subway lines, an urban landfill and an abandoned storm sewer, each located along the alignment.

Lachel provided tunnel engineering services to the HDR-led team during design.  The work included site reconnaissance of the proposed route; researching historical geotechnical information, borings and MARTA construction drawings; developing tunnel and shaft designs; and preparing associated plans, specifications and the project Geotechnical Baseline Report. 

During construction Lachel provided construction management services including review of contractor submittals and value engineering proposals.  Lachel’s involvement in the value engineering effort increased the City of Atlanta’s savings from $440,000 to more than $2,000,000.