Iowa Department of Natural Resources
Environmental Services Division

For Immediate Release
	       May 24, 2007

HEAVY RAINS LEAD TO WASTEWATER BYPASSES

MEDIA CONTACTS: Kirk Mathis at (712) 243-1934.

DES MOINES -- Heavy rains Wednesday evening and into Thursday
overloaded wastewater treatment systems throughout southwest Iowa,
leading to a number of wastewater overflows.

Heavy rain can overload wastewater collection systems, which are the
underground sewer pipes that carry sewage to a treatment plant. With the
sewage pipes overwhelmed, the excess water has nowhere to go, and can
backup into basements through floor drains. Bypassing can lower the
water level in the collection system, keeping sewage from backing up
into basements, which would present greater and more immediate health
risks than discharging wastewater into a stream.

These types of situations can occur when large amounts of rainwater or
snowmelt, also called storm water, enter a sanitary sewer from cracks in
sewer pipes, or improper connections, such as roof drains or sump pumps
hooked up to the sanitary sewer system instead of the storm water
system. The storm water should enter the storm sewer system, which
receives no treatment before entering a stream or lake. Instead, storm
water enters the sanitary sewer system (which treats wastewater from
homes and businesses).

In addition, some communities use equalization basins or storage ponds
to handle excess flow from large rain events. These basins hold incoming
wastewater until the plant catches up and can treat it. However, in
extremely heavy rain events, some facilities must discharge from these
basins and ponds to maintain their structural integrity or to prevent
the plant from flooding. Other times, lagoons used for treatment can
fill up quickly from increased flow and rainfall, and must discharge to
maintain their structural integrity.

According to DNR design standards for construction of new wastewater
treatment systems, facilities should be able to handle the amount of
water in the collection system from all three of these events happening
at the same time:
*	Peak sewage flows from homes, businesses and industry
*	Peak groundwater levels
*	A storm that drops two inches of water in an hour.

While many collection systems in Iowa already have or are in the
process of upgrading their collection systems to handle these events,
many more need to upgrade.

The DNR tracks bypass reports submitted by facilities and follows up
with the facility to determine problems and help them upgrade their
systems, although it can be a long-term process. The DNR has also formed
a committee to discuss how it handles wet weather bypasses.


Adair County
Adair: The City of Adair began discharging untreated wastewater from
its treatment plant and a lift station to the Middle River early
Thursday. The city will monitor the ongoing bypass.

Greenfield: The City of Greenfield began discharging untreated
wastewater from the equalization basin at its treatment plant to the
Thompson River at 8 a.m. Thursday. The basin is full and overflowing due
to heavy rainfall. The city's wastewater operator will monitor the
ongoing bypass.

Stuart: The City of Stuart's wastewater treatment plant was unable to
keep up with excess flows following heavy rains, leading it to begin
discharging wastewater early Thursday morning. Some wastewater is
receiving partial treatment before it is discharged to Long Branch
Creek; other wastewater is discharging directly to the creek without
treatment. The partially treated wastewater is discharging at a rate of
160,000 gallons per day, while the untreated wastewater is discharging
at a rate 80,000 gallons per day. The city estimates the bypass may last
for six to seven days, and is monitoring the situation. Officials at
Diamondhead Lake have been notified of the bypass.

Cass County
Cumberland: The City of Cumberland's lift station could not keep up
with heavy rainfall, leading the city to discharge untreated wastewater
at a rate of 200,000 gallons per day. The bypass began around 6 a.m.
Thursday and is discharging to Hoyt's Branch, which flows to Seven
Mile Creek. The city's wastewater operator will monitor the ongoing
bypass.

Guthrie County
Guthrie Center: The City of Guthrie Center began discharging untreated
wastewater from a lift station at 8:45 a.m. Thursday to prevent sewer
backups into basements following intense rains. The wastewater is
discharged to a drainage ditch that leads to the South Raccoon River.
The city's wastewater operator will monitor the ongoing bypass. The
Des Moines Water Works has been notified of the bypass.

Montgomery County
Red Oak: Untreated wastewater is discharging from two manholes in Red
Oak to the East Nishnabotna River. The discharge began at 6 a.m.
Thursday to relieve pressure on the sanitary sewer and prevent sewage
from backing up into basements. The city will monitor the ongoing
bypass.

Stanton: The City of Stanton began discharging untreated wastewater
from its main lift station to the Tarkio River at 9:30 p.m. Wednesday.
The lift station could not keep up with heavy rainfall. The city is
discharging wastewater at a rate of 130,000 gallons per day. The
city's wastewater operator will take water samples and continue to
monitor the ongoing bypass.

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