Master Planning Collection Systems in a Time of Uncertainty: Climate Change, Adaptive Management, and Defining New Levels of Service

Regardless of the cause of climate change, it is occurring and municipalities across the country will need to adapt to the changing conditions. The two major impacts of climate change affecting collection systems are sea level rise (SLR) and changes in precipitation patterns. Another factor that compounds the effects of SLR is storm surge. Historically, precipitation patterns have exhibited stationarity, meaning the statistical patterns have insignificantly deviated over an extended time period. Since the assumption of stationarity of precipitation patterns in the future may no longer be appropriate, historic collection system level of service (LOS) metrics, such as design storms, may need to be adjusted in the future. This paper discusses how adaptive management can help in defining new LOS for the next generation of collection system master plans, which are needed to protect our extensive sewer infrastructure and increase resiliency in a changing climate. Climate change predictions as well as adaptive measures developed by several municipalities are highlighted.