Communities who have helped clean up their rivers and streams were praised at the first Morgan Foundation River Awards on Thursday night.
The grand prize went to the people of the lower Shag River in Otago.
Fish and Game staff declared that stretch of water nearly dead in 1996 because of farming practices in the region.
But that all changed when streams were fenced and cattle bridges and water troughs were installed.
The river is now thriving, and its levels of E. coli bacteria - an indication of faecal contamination - have dropped an average 13% a year.
Work on the Sherry River in Motueka and the Hills Creek in Upper Hutt won community awards.
Both have become clean enough in recent years for people to safely swim.
