I've been playing around with the Environment Canada (Water Office) hydrometric website. There are a lot of inconsistencies in data sets, but it can be pretty interesting and informative if you spend some time with it.
I've found that one of the best ways to use the service (for me) is to compare historical archives (graphically illustrated) with current real-time statics (if the station appears to be maintaining accurate records). Here is an example:
Station 10PA001 (Coppermine River Below Desteffany Lake). You can see that the historical archive compares minimum levels, maximum levels, and 2009 levels. The current chart indicates flow peaking on/around June 06 at "70 m3/s," which is about 30% less than 2009 levels, and is a good deal less than the historical maximum level. The spring freshet appears to be a few days later than average as well. This is also confirmed when I look at records for other stations. One note:
the water office website contains a pretty powerful caveat that these records are measured electronically from remote stations, and may not reflect actual conditions.