If you've visited Woodbine Beach recently, you might've noticed several underwater tube-like contraptions near the harbour at Ashbridges Bay. 

These 'port protection maintenance holes' are located at all 50 risers located along the lakebed, between 15-20 metres under Lake Ontario.

The holes are all part of the city's efforts to improve lake water quality in the Lower Don River, Taylor-Massey Creek, and Toronto's Inner Harbour by keeping combined sewer overflow out of our waterways. 

Ashbridges Bay Treatment Plant Outfall achieved another major construction milestone as part of our efforts to improve lake water quality by installing port protection maintenance holes at all 50 risers located along the lakebed, between 15-20 meters under Lake Ontario. pic.twitter.com/PxYZro2k3P

— City of Toronto (@cityoftoronto) November 30, 2022

The maintenance holes are just another major construction milestone as part of the Don River and Central Waterfront & Connected Projects, which is Toronto's largest and most significant stormwater management program. 

This is a major milestone before the onset of winter in the Lake and another step in the Don River Central Waterfront project: https://t.co/PdCBfNeUoi
#Toronto #TorontoConstruction #Infrastructure #DRCW

— City of Toronto (@cityoftoronto) November 30, 2022

The projects have a whopping budget of $3 billion, and began construction back in 2018. 

According to the city, water quality in the Lower Don River, Central Waterfront and Taylor-Massey Creek has degraded due to combined sewer overflows, stormwater runoff, and erosion and sediment conditions. 

The projects will address these issues in order to significantly improve water quality in the aforementioned areas, enhance recreational uses such as swimming, and improve habitats for fish and other wildlife.