CORRECTING WET WEATHER SSO PROBLEMS IN BITE-SIZED PIECES

Correcting a defective sanitary sewer collection system can be a daunting task, particularly when considering the total amount of resources necessary to transform its current state into a suitably improved state. As with any large project, breaking the problem down into more manageable subtasks staged over a period of time can simplify the effort and make it more practical to undertake. The City of Niagara Falls, New York is taking such an approach in dealing with levels of infiltration and inflow in its collection system that are creating service problems for residents, and impacting its ability to redevelop the eastern portion of the city.The region was divided into three areas where detailed infiltration and inflow studies were conducted in three consecutive years. Components of each study include thorough sewer cleaning, video inspection of all sewers, dry weather and wet weather inspections, smoke testing, dye testing, sewer flow measurement, groundwater level measurement, rainfall measurement and water quality monitoring. The city took a “partnering” approach in working with the engineering consultant and subcontractors in order to realize performance gains from rapid correction of defects with in-house resources. The use of in-house resources also reduced costs. More extensive corrective work is prioritized for future implementation by contractors, also phased over a multi-year period.A reevaluation of region-wide performance will be conducted once all high priority measures have been accomplished. The understanding and cooperation of the state environmental regulatory agency has proven vital to undertaking the program and achieving significant progress, without imposing undue financial hardship upon the residents and ratepayers.