Our work - Blue Lake dawning

Blue Lake (Rotomairewhenua) is a sub-alpine lake within the Nelson Lakes National Park with exceptional optical purity. NIWA has been studying the remarkable clarity of this water body since 2010, which has been measured at a horisontal under-water range of up to 80m at times. This makes it the most visually clear freshwater yet reported. [Marty Flanagan]