Canterbury Water Quality
New Zealand's 'Environment Canterbury' believe they are the first to create a Google Maps mash-up showing water quality in rivers, lakes and the sea. The mash-up takes water quality data from ECan's GIS system and integrates it with Google Maps to provide a dynamic method for accessing Canterbury's water quality information on-line.
Swimming locations in the area are each tagged with a colour coded map marker (with a red marker warning you not to swim and blue markers representing very good water quality). It is possible to select a region of Canterbury from a link in the sidebar. When you click on a link the map zooms to that region and also loads links to swimming locations in that region into the sidebar.
So if you are enjoying the New Zealand summer and you fancy a swim do your self a favour and check this map for clean waters before leaving home.
Update: Ouseful was so inspired by this water quality map that he decided to create his own water quality map for the UK. He has a great article on his blog about how he created a map of UK Blue Beaches by using Yahoo Pipes to create a kml and then importing the kml into Google MyMaps to tidy up the geo-coding.