MAWSS Proposes Containment System to Alleviate Wet Weather Overflows

To alleviate sanitary sewer overflows that occur periodically at the Halls Mill Creek Lift Station, near Riviere DuChien Road, Mobile Area Water and Sewer System (MAWSS) will be constructing a Severe Weather Attenuation Basin (SWAB) at the lift station site for storing elevated flows in the sewer system caused by storm water infiltration. When the rainfall and flows subside, the captured flow will be returned to the sewer system for conveyance to the treatment plant. The SWAB also provides the capability to divert flows from the lift station if needed for maintenance of the station or its force main. The basin will consist of four storage cells or ponds having a total capacity of 20 million gallons. Typically, one cell would be utilized at a time. The other three would fill only as needed.

The concept of using storage for reducing wet weather flow in a sanitary sewer is not new. The SWAB for the Halls Mill Creek Lift Station is similar to one being used effectively in Bay Minette. The Bay Minette basin is located near a residential community and has nearly eliminated sanitary sewer overflows in that system. The basin has had no negative impacts on the community whatsoever. The presentation linked below was prepared for community meetings by CH2M, the engineering firm that designed and built the basin in Bay Minette. For additional information about this project, contact Daryl Russell, Planning and Engineering Manager 694-3197.

SWAB Presentation