If you've ever wondered about the health of your local river or lake, seven million open data points are now at your fingertips. Information ranging from lake temperatures to levels of nitrates in the water is available on Great Lakes DataStream, a new online platform for sharing water quality data from across Ontario and Quebec. It's going live during international Open Access Week, a global celebration of the power of open data – information that is free to look at and reuse – that runs until October 31.