GMB was retained by the Dorchester County Sanitary District to prepare a USDA Preliminary Engineering Report and Environmental Report for the Madison-Woolford Sanitary Sewer system. Design began in 2008 and consisted of a low pressure sewer system with individual grinder pump stations for each property. Approximately 340 existing residences and businesses were served with simplex or duplex grinder pump stations. Low pressure sewers ranged from 1 ¼” to 5” diameter. Over 148,000 feet of low pressure sewer was installed. The project included connecting the existing houses to the system, starting up the grinder pump stations, and abandoning the existing septic tanks.
The low pressure sewer systems discharged to two Regional Pump Stations with duplex submersible pumps and backup stationary generators. The Woolford Pump Station has a 10’ diameter concrete wet well and a valve vault. The existing Church Creek Pump Station was demolished and a new 10’ diameter concrete wet well and valve vault were constructed on the same property. The existing pump station stayed in service during construction of the new station. The 8-inch diameter force mains from the Woolford PS and the Madison PS were 19,858 feet and 17,357 feet long, respectively. The low pressure sewer and force mains were installed via directional drilling (including under tidal wetlands and intersections), trenching, and open cut methods.
During construction, GMB was responsible for contract administration and full time inspection. Services consisted of shop drawing reviews, addressing Contractor questions, review and approval of monthly payment requisitions, monthly progress meetings, as-built drawings, daily inspection, punch list generation, pump station startup, and operation and maintenance manual review.