Bettendorf city officials appear ready to sign a consent order with the Iowa Department of Natural Resources (IDNR) calling for $32 million in sewer system upgrades over the next 20 years.
The agreement with the IDNR was outlined to the city council Monday (2/4) by engineering consultants Veenstra & Kimm and aldermen are expected to vote on the deal next month.
Failure to come to an agreement on the sewer system improvements and follow through with the upgrades would jeopardize expansion of the city's sewer capacity needed for future developments like the new I-80 and Middle Road corridor, city staff told the council. The IDNR sent the proposed order to the city last August after several years of negotiations on how to address so-called sewage "bypass" flows at the Davenport treatment plant, which is one-quarter owned by Bettendorf.
During periods of heavy rain, water infiltrates sewer lines, creating flows which the plant can't handle and resulting in the dumping of partially treated sewage into the Mississippi River. Davenport discharged a total of 548 million gallons of partially treated wastewater into the Mississippi River over 74 days in 2010. When the treatment plant was unable to process all the sewage flow in 2010, the sewage backed up and Bettendorf pumped more than 33 million gallons of untreated wastewater into the river.
And, in 2009 Davenport discharged a total of 724 million gallons of partially treated sewage into the Mississippi River during 90 separate days, according to the IDNR.
The IDNR and U.S. Environmental Protection Agency have been meeting with city officials over the past two years to work out an agreement to address the sewage system problems rather than pursue legal action against the cities over the discharges.
The planned upgrades would include identifying where sewer interceptor lines along the riverfront are allowing storm water to infiltrate into the sewers, cleaning and repairing the large interceptor lines and upgrades to the sewage treatment plant in Davenport, jointly owned by Davenport, Bettendorf, Riverdale and Panorama Park, to handle peak flows to the plant that occur during heavy rainfall and when the Mississippi River nears flood stage.
Veenstra & Kimm engineers said such "wet weather" flows can be more than five times the normal treatment capacity of 17 to 21 million gallons per day.
The engineers said by reducing the amount of storm water that infiltrates into the sewage lines and sent to the treatment plant, they hope to reduce the size of future sewage treatment plant expansions or equalization basins to handle such wet weather flows.
Overall cost of the 20-year improvement plan is more than $160 million, including $128 million for Davenport, $32 million for Bettendorf, $738,000 for Riverdale and $112,000 for Panorama Park.
CLICK HERE to download the sewer system upgrade overview.
