By Jon Willing, Ottawa Citizen, April 11, 2017
A perfect storm of springtime activity caused nearly 600 million litres of diluted sewage to pour from city pipes into the Ottawa River over five days.
Spring showers melt the snow and all the water runs into the sewer system. The city has a network of older combined sewers that carry both sanitary sewage and stormwater. When the sewers fill with liquid, the overflow is pushed out into the river.
Several days of dreary weather in the capital made the overflow particularly large.According to the city’s records, about 598 million litres of combined sewer overflow ran into the river between April 4 and April 8.
http://ottawacitizen.com/news/local-news/spring-freshet-blamed-for-598-million-litres-of-diluted-sewage-dumped-in-ottawa-river