Toronto's Eastern and Island Beaches
The Don River is one of Canada's most degraded urban rivers. Contaminated stormwater runoff and combined sewer overflows are the primary sources of pollution.
The Don River is 38km long, extending from the Oak Ridges Moraine to Lake Ontario. Over 800,000 people live in the watershed, which is 80% urbanized. Soils conditions fluctuate between high and moderate permeability to low permeability.
There are 30 combined sewers along the Don River and Massey Creek that overflow with raw sewage 50-60 times a year. E.coli tests performed in the river have frequently measured levels of 100,000 E.coli/100ml. The highest level ever recorded was 300,000 E.coli/100ml.
Seven city beaches are located near the mouth or 'base' of the Don River - three beaches on Toronto Island plus Cherry, Woodbine, Kew and Balmy beaches. There are also CSOs along the lakeshore.
Surprisingly, these beaches are also some of Toronto's cleanest and are safe for swimming significantly more days during the summer. There are a few reasons for this: (1) Toronto's Portlands separate the mouth of the Don River from the lakeshore, diverting the polluted water into Lake Ontario, west of the beaches; and, (2) The City of Toronto has built underground storage tanks to intercept combined sewer and storm sewer overflows. The captured overflow is pumped to a treatment plant.
However, there are still E.coli and beach closure problems.
Centre Island has been plagued with rising E.coli levels after a bird pollution began frequenting the area. Cherry, Hanlan's Point and Ward's Island Beaches are sometimes affected by E.coli carried in currents from either the mouth of the Humber or Don Rivers.
Woodbine Beach, although protected by a storage tank, is in close proximity to a CSO at the bottom of Kenilworth Avenue on the lakeshore. This CSO overflows periodically once tank capacity has been exceeded.
Kew and Balmy Beaches remain susceptible to CSOs. The storage tank in this area may have been built to small to handle the volume of overflow or the area is experiencing heavier and more frequent rain storms than anticipated and the tank is overflowing more often than intended.
Additional Pollution Problems
There are 1,185 stormwater outfalls along the Don River and Massey Creek. This volume of polluted runoff contributes to 71% of the river's total flow. Major highways such as the DVP, 401 and Bayview Extension contribute toxic metals, chemicals and road salt pollution to the river.