City and Borough of Juneau
Wastewater Utility Division
Combined Sewer Overflows:
Occasionally, the Wastewater Utility finds it necessary to divert a combination of domestic sewage and storm water to Gastineau Channel. These events are called Combined Sewer Overflows (CSOs). CSOs occur when the sewer system experiences extremes in flow, usually caused by heavy rains. Though very infrequent, CSOs can also be caused by equipment failures, such as a leak developing in the pressure sewer between the pump station and the treatment plant.
A CSO is manually initiated by the crews, usually when either the storage capacity of the sewer collection system is exceeded or when the flow of wastewater through the treatment plant has become too high to properly treat it.
Water being diverted is routinely very dilute because is is made up primarily of storm water. Still, these events are kept as short in duration as possible. This water is also quantified and tested. This means that the amount and composition is tracked as required by the Environmental Protection Agency (EPA).
Following is a list of public notices begun in the Fall of 2004 in an effort to make the public aware of these events and to fully comply with the EPA discharge permit.
2005 Combined Sewer Overflow Notices
No Combined Sewer Overflow for 2006