Hammond mayor: August rain overwhelmed sanitary system; Columbia Avenue basin discharged into Grand Calumet River

Mayor (name not specified) told the Hammond City Council that a heavy rain event between Aug. 17 and Aug. 18 flooded large parts of the city, overwhelming the Hammond Sanitary District and causing a combined-sewer overflow (CSO) into the Grand Calumet River.

The mayor said the storm dropped between "6 and 8 inches of rain" across Hammond and that the wastewater treatment plant peaked at about 160,000,000 gallons per day — nearly three times its design capacity of about 68,000,000 gallons per day. He said the Columbia Avenue Retention Basin filled and "discharged over 100,000,000 gallons of partially treated water into the Grand Calumet River," which he described as a CSO event the city must report to the U.S. Environmental Protection Agency and the Indiana Department of Environmental Management.

The mayor said roughly 200 reports of basement backups were received across the city, with about half in the Robertsdale neighborhood. He said flows remained elevated for days after the storm and that the plant did not drop below rated capacity until roughly a week later. He thanked Hammond Sanitary District crews for working around the clock and expressed sorrow to residents whose homes were damaged.

Council members and the mayor discussed household-level flood mitigation. The mayor and several council members urged homeowners to consider installing check valves to reduce basement backups. A council member noted a possible funding source if a proposed data-center pilot program — described in the meeting as a potential $4,000,000-per-year pilot — were approved, suggesting some of that money could be used to subsidize check-valve installations; that suggestion was discussed but not adopted as a formal action. The mayor also responded to recurring public questions about ‘‘gates’’ in the sanitary system, saying repeatedly that "there are no gates to open" and that the system is a gravity-flow system aided by pumps.

Public comments later in the meeting connected storm risk to local land-use decisions. A member of the public who spoke about tree removal and a city-sponsored event warned that cutting old-growth forest would worsen flooding; she urged the council to avoid removing mature trees that help reduce runoff.

No ordinance or formal change to sanitary operations was adopted at the meeting; the discussion was a report and an exchange of ideas. The mayor said the city will continue to pursue system-level protections and encouraged residents to take steps to safeguard their properties.

Clarifying details reported in the council record included the mayor's estimates of rainfall and flows, the retention basin discharge, the number of resident calls about basement backups, and the treatment-plant design capacity. The council did not adopt new regulation or a specific funded program during the meeting.

The council did not vote on any storm-related ordinance at this meeting; a suggestion about using pilot funds for check valves was discussed only as an option.

Residents seeking follow-up were advised during the meeting to contact the mayor's office or constituent services for information about storm response and neighborhood-specific assistance.