Another year with heavy rainfall. Another year with flooding. And, another year of pumping raw sewage into the Mississippi River.
The all-too-familiar scenario is playing out again along the Bettendorf and Davenport riverfront as the Davenport Wastewater Treatment Plant struggles to cope with high flows – a combination of storm water runoff, flood water and sewage – resulting in the backup of interceptor sewer lines along the Bettendorf and Davenport riverfront.
Bettendorf activated its pumps along the riverfront near Leach Park and the Isle of Capri Casino June 29, according to reports filed with the Iowa Department of Natural Resources (IDNR), and in just the initial hours pumped 1.3 million gallons of raw sewage mixed with storm water into the river. The pumps have been pumping since, and a full tally of the sewage disposed in the river is expected when the pumps are turned off. Pumps were still on as of today (10/10) at three locations along the Bettendorf riverfront.
Davenport also reported bypassing of sewage June 30 at the River Drive and Howell St. lift station as well as 11 sewage back-ups in basements and nine sewage manholes overflowing between July 1 and July 3.
During the wet March-June period in 2013, Bettendorf flushed more than 200 million gallons of untreated sewage diluted by storm water into the Mississippi River.
When the inflows during heavy rain events become too high, the Davenport treatment plant (jointly owned by Bettendorf), lowers the inflow gate to the facility to prevent it from being overwhelmed by the sewage/stormwater runoff. When that occurs, the plant also begins "bypassing" the secondary treatment of the sewage, pumping the sewage into the Mississippi River after only primary treatment. Such "wet weather sewage bypass" was at the heart of recent lawsuits involving the Iowa League of Cities and the U.S. Environmental Protection Agency (EPA).
Bettendorf and Davenport signed a consent order in 2013 with the Iowa DNR and the EPA outlining a schedule of sewage treatment plant and sewer line improvements aimed at curbing the bypassing of sewage and eventually end the pumping of raw sewage into the river. The order outlines a 20-year $160-million improvement plan including cleaning and repairing of large interceptor lines along the riverfront and upgrades to the sewage treatment plant.
Engineers hired to analyze the sewage treatment system say the "wet weather" flows can be more than five times the normal treatment capacity of 17 to 21 million gallons per day.
One of the improvements local officials have been blaming for part of the infiltration of water into sewer lines involves a large interceptor line owned by the U.S. Government upstream from Lock & Dam 15. The large pipe is the responsibility of the U.S. Army Corps of Engineers, which recently awarded the contract to clean out and repair the line.
Rock Island District Corps officials said the work on the sewer line improvement was to have begun, but the high water has delayed the project start. The work on the line is expected to be complete this fall. Since the project is being funded out of the Corps' normal operation and maintenance budget, the project did not have to wait for a special earmark from federal officials.
