• Please stay on the line: Putting I&I on hold with SSO Tanks

  • Project Components:
    Conference Presentation, Wastewater
Please stay on the line: Putting I&I on hold with SSO Tanks
2016 BC Water and Waste Association (BCWWA) Conference

KWL's Andrew Boyland and Samantha Ward from the City of Surrey made a presentation at the 2016 BCWWA conference in Whistler, BC.


For many municipalities, Inflow and infiltration (I&I) is a complex, and expensive, problem to solve.  For example, the City of Surrey (City) has spent close to $5 million on various I&I management programs.  The results, however, have been mixed with many catchments still measuring I&I rates over the City’s committed maximum of 11,200 L/ha/day. 

Looking for innovative ways to reduce its I&I impact to the regional interceptor system, the City embarked on a novel study to determine whether it was feasible to use Sanitary Sewer Overflow (SSO) tanks to reduce the peak flows associated with excessive I&I.  Sizing an overflow tank was a complex process for this project because of Surrey’s explosive growth over the last decade, the lack of extensive flow monitoring data, and the complex nature of this extremely large system, which results in long transit times and attenuated peak flow rates.  Kerr Wood Leidal and the City developed a new method to determine the required SSO tank size using a combination of techniques to estimate the current 5-year storm wet weather flow hydrograph, and compare this with the sewer capacity allowance.  The results are surprising, and could change the way Metro Vancouver municipalities think about liquid waste management planning.

Stream8_BoylandA_WardS_05032016.pdf (application/pdf, 1.903Mb)