Leavenworth's wastewater treatment plant is treating water that it doesn't need to, and it's costing the city money.
But city officials have a plan for reducing what is called inflow and infiltration into the sanitary sewer system.
Mike McDonald, director of public works, said there are a variety of ways the excess water can end up in the sewer system including manhole covers that have been knocked loose, broken sewer lines and down spouts connected to the sewer.
The city of Leavenworth contracted with George Butler Associates to study the issue. The architectural and engineering firm developed a plan for addressing the problem.
According to the executive summary for a GBA report, reducing the inflow and infiltration in the sanitary sewer system can lower costs associated with wastewater treatment plant permit requirements.
Reduction of inflow and infiltration also can offset a reduction in the revenue the city receives from Fort Leavenworth for its share of sewer treatment costs. The reduction in revenue has come as the Army post has lowered its own inflow and infiltration, according to the executive summary.
The plan of action developed by GBA focuses on making improvements in the Three Mile Creek watershed area. The area has been divided into several mini-basins.
The plan focuses initial efforts within two basins, Nos. 3 and 4, that have been deemed as priorities. A third basin, No. 2, will be used as a control basin for evaluating the effectiveness of the work.
Basin 3 is located mostly southeast of Broadway and Metropolitan Avenue. Basin 4 is located mostly southwest of 10th Avenue and Spruce Street.
The work initially will focus on publicly-owned infrastructure.
The estimated cost for the initial public sector work for Basins 3 and 4 is $1.8 million.
McDonald said the city budgets about $500,000 per year for sewer repairs. That money can be used to reduce inflow and infiltration. He said the project won't require a sewer rate increase.
"This is all currently in the existing rate structure," he said.
The city recently increased sewer rates by 25 percent. But that rate increase was imposed to help pay for a disinfection system at the wastewater treatment plant required by state and federal regulation.
When the plan for reducing inflow and infiltration was reviewed this week with Leavenworth city commissioners, City Manager Scott Miller said the work will be a long-term project.
McDonald said the initial phase probably will take two to three years.