X Marks the Spot – identifying cross connections that can lead to pollution
Walking Lunch: X Marks the Spot – Identifying Cross Connections that Can Lead to Pollution
Join Fred Dillon, the City’s of South Portland’s Stormwater Program Coordinator, on a short walking tour and demonstration of some basic methods used to track down potential sewage discharges into the stormwater system. The City may also be able to provide a closed circuit TV inspection unit used to further identify potential “cross-connections” between the sewer and separated stormwater systems.
The Clean Water Act’s National Pollutant Discharge Elimination System (NPDES) consists of 2 main branches: one for wastewater discharges and for “separated” stormwater discharges. Ideally these discharges should be completely distinct but can occasionally mix due to aging infrastructure and outdated design and construction practices. Consequently, NPDES regulations require communities with Municipal Separate Storm Sewer Systems (MS4s) to detect and eliminate potential “illicit” (prohibited) discharges conveyed through publicly owned stormwater drainage infrastructure. Sewage is an illicit discharge and is a particular concern for coastal swim beaches due to possible public health impacts.
Detecting and eliminating illicit discharges – especially sewage – into separated stormwater systems can be very difficult, time consuming and expensive. Even so, MS4 communities are tasked with conducting annual dry weather inspections of stormwater outfalls to identify illicit sources of pollution. For the past 4 years, South Portland has partnered with the Maine Healthy Beaches Program to identify potential sewage sources in the Willard Beach stormwater system.