The City’s sanitary sewer collection system transports all flow from residential, commercial, industrial and tax-exempt properties in La Crosse to the wastewater treatment plant. Additionally, flows from other areas that contract with the City for sewer service are transported through the City’s system to the wastewater plant.
The first sewers in La Crosse were installed in the 1880s and were routed to discharge raw sewage directly into local rivers and receiving streams. This practice continued until construction of the City’s first treatment plant was completed in 1936.
The early collection network was a combined sewer system that collected sanitary sewage, rainwater, snowmelt and other clear water and combined these flows into the same pipe. The original, combined sewer system was eventually separated into sanitary and storm systems. Additional separation of clear water discharges into the sanitary sewer system occurred quickly following implementation of the Sanitary Sewer Utility in 1991.
Presently, the sanitary sewer system serving the City of La Crosse consists of over 188 miles of gravity and pressure piping, as well as 26 pump stations. Collection system piping ranges widely related to age, diameter and pipe material; some of the pipe installed in the late-1800s is still in service. Similarly, the system includes many generations of pump stations which vary in design and pumping capacity.
The La Crosse Sanitary Sewer Utility is responsible for the collection system serving City properties, as well as the system remaining in Shelby Sanitary District #1. Other users under contract with the City for sewer service, including the Cities of Onalaska and La Crescent, the Town of Campbell, and Shelby Sanitary District #2, are responsible for operation and maintenance of the sanitary sewer systems serving their areas.
Operation of the sanitary collection system includes ongoing, scheduled flushing/cleaning of gravity sewers (one-third of the entire collection system is flushed annually), and systematic, scheduled preventative maintenance of pump stations. Major pump stations are visited daily by Utility maintenance personnel; smaller stations are checked at least once per week. All pump stations are monitored as part of the Utility’s automated control system.
Historically, collection system maintenance information has been reported to the Wisconsin DNR as part the Utility’s Compliance Maintenance Annual Report (CMAR). As part of compliance with its current WPDES permit, the Utility is currently developing a written Capacity, Management, Operation and Maintenance (CMOM) program. This program will formalize the City’s sanitary sewer operation and maintenance procedures, including mandated, specific self-auditing, record-keeping and reporting.