An investigative report was released today by Ecojustice (formerly Sierra Legal Defence Fund) that highlights innovative green solutions that could stop billions of litres of raw sewage from fouling the Great Lakes each year. Green Cities, Great Lakes: The Green Infrastructure Report reveals that at least 89 Ontario municipalities have combined sewer systems, which is antiquated infrastructure that carries sewage and stormwater runoff in a single pipe, frequently causing overflows of untreated sewage into local waterways during wet weather. The report also provides practical examples of green infrastructure techniques used in various cities, including Toronto, St. Catharines and London, Ontario, to reduce the frequency and severity of water contamination from combined systems.
“Although the pipes are hidden from view, we routinely see the symptoms of combined sewer overflows: beaches closed to swimming; fish that are unsafe to eat; excessive algae and weed growth, and diminished biodiversity,” said Ecojustice researcher and report co-author Liat Podolsky. “Some cities are starting to mitigate the impact of CSOs by adopting green infrastructure solutions which mimic natural systems and reduce the volume of water entering the sewer during storms.”
While Canadian cities grapple with the estimated $30 billion needed to immediately replace and upgrade antiquated water and wastewater infrastructure, the report calls for an approach that focuses on preventing water from entering our wastewater systems in the first place. It provides several case studies and practical examples of communities that have already invested in green infrastructure, such as green roofs, engineered and natural wetlands and forests, downspout disconnections, and permeable pavements.
“With increased urbanization, green spaces like wetlands and forests have been paved over with hard surfaces that quickly channel vast amounts of stormwater into the combined sewers,” continued Podolsky. “Incorporating green infrastructure into the urban environment allows cities to restore hydrologic function and ensure that combined sewer systems are not constantly overwhelmed. Simply put, green infrastructure can help get the rain out of the drain and keep raw sewage out of our lakes and rivers.”
In the absence of government reporting on CSOs, Ecojustice released in 2006 the Great Lakes Sewage Report Card, which revealed more than 90 billion litres of overflows each year from 20 cities alone. The Green Infrastructure report calls for the Ontario government to start reporting the volume and frequency of CSOs. It also provides several recommendations, urging municipalities to adopt green infrastructure into all aspects of planning and development and demanding that senior levels of government increase funding and improve all aspects of monitoring, reporting and enforcement.