this site is good for some of the welsh rivers
http://www.welsh-rivers.co.uk/river-levels-home.php
a site to check the wye
http://www.wyeuskfoundation.org/conditions/gauge8.php
vimeo and youtube are great for seeing the lines and getting an idea of the river your looking at going to.
keeping the sites clean
most importantly
https://plus.google.com/116418513583992259902/about?gl=uk&hl=en
the home of wombourne kayak club on a thursday around 11pm