The Don River is the single channel where most of the runoff water upstream in Richmond Hill, Markham, and  northern parts of Toronto flows through before it reaches Lake Ontario. With the two major tributaries, the east Don and the west Don, moderate to heavy rainfall can cause water levels to rise very quickly, cresting over to flood nearby roadways. Sections of Bayview Avenue are prone to such flooding as it is at an elevation nearly flush with the Don River. 

During a flood event in sections of Bayview Avenue, the Road Operations crew currently must travel to the location to manually set up roadblocks to divert traffic. This usually involves multiple trips and detours around already flooded parts of the road network which adds to the closure time. This delay means the flooded sections cannot be closed off in the  most timely fashion allowing drivers to potentially get stranded in the flooded areas. Furthermore, information of flooding is currently only conveyed via broadcast media limiting traveler’s awareness of a flooding event.

To provide a more proactive, responsive, and efficient means of carrying out road closures during a flood event, City Council directed City staff to undertake the design and deployment of an automated gating system in flood prone sections of Bayview Avenue.

Here is the link that provides an explanation of the project:

http://app.toronto.ca/tmmis/viewAgendaItemHistory.do?item=2013.EX34.4