GeoSurvey provides surveying support for the construction of the West Area CSO Storage Tunnel and Pumping Station in West Altanta 

Recently GeoSurvey was requested to provide surveying services related to the construction of the West Area CSO Storage Tunnel and Pumping Station in West Atlanta.  Our client, Atlanta CSO Constructors, requested that we establish multiple “benchmarks” along the floor of the tunnel to be used for guidance of the tunnel boring machine.

These vertical benchmarks are critical to make certain that the grades and flow within the tunnel work properly.  When completed, the tunnel will hold combined storm runoff and sewer overflow during large storm events. Following the storm, the combined runoff will be pumped to a dedicated treatment facility before flowing back into surface water. In order for the combined sewage and storm runoff to properly flow back to the treatment facilities, controlling the elevation and slope of the tunnels is critical.

A team led by GeoSurvey Crew Leaders Jason Marrow and Stephen Emberson entered the tunnel and completed a “three wire” level loop approximately 5 miles in length.  The vertical error of closure was less than .005 (five thousandths) of a foot!    

Geosurvey's results help insure that these storage tunnels flow correctly and that Atlanta's combined storm and sewage are treated properly before flowing into the area's rivers and streams.