During heavy rainfall events, the City of Aberdeen experiences extensive street flooding. Much of this flood water finds its way into the sanitary sewer system. This extra water is referred to as "Infiltration/Inflow" (I/I). Storm events can increase flows to the treatment plant beyond its processing capacity, thereby creating system backups.
To minimize the flooding problems which appear to be a major contributor of excessive I/I, the City has initiated a major storm drainage improvement project. The project involves the construction of nine large storm water pumping stations. The combined pumping capacity of the stations exceeds 60,000 gallons per minute. Funding has been secured for the construction of all the stations and all of the pumps have been ordered. Designs have been completed, contractors selected, and construction is in various stages on the seven largest pump stations. Design work is being finalized on the two smallest stations. All work is anticipated to be completed this winter.
The City has also completed an extensive smoke-testing program and has identified over 250 locations where private property owners were draining either rainwater or ground water into the sanitary sewer system. The City is taking aggressive action in having all of these private problems corrected.
Throughout the coming winter, spring, and summer, the City will be involved in other programs to eliminate private sump pumps that discharge ground water to the sewer system, correct faulty plumbing that drains water from crawl spaces into the sewer, sea] manhole lids, and investigate a variety of locations on private property that have been identified as sources of I/I.
Rather than spending millions of dollars to increase the capacity of the treatment plant to meet the peak events created by winter rain storms, the City will be doing everything possible to prevent that extra water from getting into the system.
Concern has been expressed that the connection of the Stafford Creek Correctional Center will create problems at Aberdeen's waste treatment plant when the City experiences high sewer flows during storm events. The City has addressed this concern by constructing a 1,560,000-gallon sewage storage tank at the Stafford Creek Correctional Center site. This large storage tank will be used to detain the sewer flows from the facility during periods of high treatment plant flows. The flows from the facility will then be pumped to the treatment plant after the storm is over and plant flows are lower.
LARRY D. BLEDSOE, P.E.
Director of Public Works
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