Number of Reportable Wastewater Overflows per 100 Miles of Wastewater Lines per Year
A reportable Sanitary Sewer Overflow (SSO) is an overflow that originates from/or is caused by City of Austin owned sewer components, and reaches storm drains or waterways. Sewage that reaches storm drains or waterways, or is of a significant volume, could result in health and environmental hazards, including contaminating water wells with disease-causing agents. This measure is an important indicator of the effectiveness of the operation and maintenance of the wastewater collection system.
For this calculation, the number of reportable sanitary sewer overflows is divided by the miles of wastewater main.
FY 2015-16 Results
The goal for this measure is less than three (3.0) reportable overflows. The result of 2.90 was 0.10 below the goal and below the previous two fiscal year results. A low number of SSOs indicates a higher functioning wastewater collection system, effective operation and maintenance activities, and efficient repair practices, lowering the potential for enforcement actions by regulatory agencies.
Assessment of Results
Ongoing efforts contributing to the number of reportable overflows include the continuation of Operation and Maintenance activities, the continuation of Capital Improvement Program (CIP) projects to rehabilitate and replace aging infrastructure, and the continuation of the Austin Water (AW) SSO response procedures to reduce the impact of sewer main backups and the volume of overflows. In addition, the use of contract construction services has expedited the complex repair of defective wastewater lines. The long-term review of this measure indicates that the collection system and emergency response procedures have made the AW service area safer from the effects of wastewater spills.
AW remains committed to managing reportable wastewater overflows. To this end, AW continues to monitor and track this measure to proactively reduce SSOs. In addition to the Clean and TV Program, CIP projects, and SSO response procedures, AW is building a system-wide condition assessment database for all wastewater mains using TV inspection software and industry-standard condition ratings. The asset management plan will direct limited resources toward the highest priority mains for rehabilitation or replacement and can be expected to reduce the number of reportable SSOs, including repeat SSOs as the plan is implemented.
For more information contact Kevin Koeller, P.E., Division Manager, at (512) 972-2055.