EPA Compliance Accomplished Fort Madison CSO Project
Stanley Consultants was hired by the city of Fort Madison, Iowa to address concerns issued by the U.S. Environmental protection Agency (EPA) about combined sewer overflows (CSOs.)
The EPA issued a Consent Order requiring the City of Fort Madison to address CSOs by either implementing disinfection of CSOs or eliminating them. There are 13 main combined sewer drainage basins in the City's sewer system. Stanley Consultants was hired by the City of Fort Madison to conduct field investigations, evaluate both the extent of separation and general condition of sewers, and recommend a separation plan and rehabilitation needs for the Thirteenth Street basin. The sewer system in the Thirteenth Street basin includes some separated sanitary and storm sewers, some combined sewers, and one CSO structure.
The methodology used to accomplish the objectives of this study included a combination of field work, data analysis, and mapping. The field work included manhole inspections and sewer televising. Mapping work consisted of using the results of the manhole inspections and televising to update the City's existing sewer maps to more accurately reflect the existing sewer system.
Field inspections were conducted on 72 manholes in the Thirteenth Street basin. Manhole defects and rehabilitation needs were identified. Based on the results of the manhole inspections and review of the existing mapping, specific sewer segments were identified to be televised. Sewer televising was conducted on approximately 11,000 feet of sewers. Each televised sewer segment was assigned a rating to designate the urgency of rehabilitation. The televising videos and reports were also compared with the existing sewer mapping in order to identify and correct discrepancies.
The results of the field investigations and updated sewer mapping for the Thirteenth Street basin were evaluated to make rehabilitation recommendations and to develop a preliminary plan for sewer separation. Construction cost estimates were prepared both for recommended rehabilitation to improve sewer system condition and for work required to separate the sewer systems and eliminate the Thirteenth Street CSO. Recommendations for additional investigative work in the basin were also made.