Hello John,
www.OpenSeaMap.org - the free nautical chart shows cayak and canoe routes with coloured grades of difficulty and river gauges in real time: http://map.openseamap.org/map/?zoom=10&lat=50.89527&lon=14.59515&...
We like to build an international *Watersport-Wiki* as SMW: Dive spots, harbours, canoe routes, fishing places, etc. and we hope for nice support from the WikiData-project :-)
Markus