At the New Zealand River Awards in Wellington on Thursday Southland's Waihopai River was named the most improved river and the Tasman River won the "River Story Award", sponsored by the Ministry for the Environment.
Department of Conservation senior biodiversity ranger Dean Nelson said better habitat for a "a whole lot of species" at the the entranceway to Aoraki/Mt Cook National Park, which welcomed more than onemillion visitors last year, was due to the work of "a whole lot of people", including landowners at Glentanner and Mt Cook Stations; volunteers on trapping projects; and Meridian and Genesis, which funded Project River Recovery.
The award helped to validate "large-scale" conservation work.
While once there were just nine or 10 pairs of the world's rarest wading bird, the kaki (black stilt), in the Mackenzie Basin, now there were 30 pairs, of which roughly half nested in the Tasman River area.
"Some of these birds that have generally been going backwards in terms of breeding success and productivity, we might only need to make a small difference to turn that around.
"And it was always recognised while it was primarily aimed at riverbed birds, there was a whole raft of other species - lizards, invertebrates in the riverbed and all that kind of stuff - that would benefit from it as as well," he said.
Conservation Minister Eugenie Sage lauded Doc and its partners for their work in the "internationally important" ecosystem.
This year judges for the most improved river award looked at a combination of E. coli levels and the macroinvertebrate community index (MCI) over the past 10 years to determine the most improved site.
The Waihopai River was improving significantly in both areas, an Environment Southland statement said, with E. coli levels dropping 6.1% a year and its MCI rising 1.9% a year over the past decade.