The Whangaehu River has won an award for the most improved river in the region and is the fourth most improved nationally.

Horizons Regional Council chairman Bruce Gordon accepted a Morgan Foundation River Award on Thursday night.

The Most Improved River Award celebrates waterways showing long-term improvements in water quality and is judged by a panel of scientists.

This year's award acknowledges improvement in E. coli levels, with the Whangaehu River showing a 10.8 per cent improvement.

"Not only was the Whangaehu River the most improved in our region, it is also the fourth most improved nationally," Mr Gordon said.

"A lot of time and resources have gone into work programmes in the catchment that contribute to improving water quality. This includes riparian fencing and planting, as well as erosion control planting, by both farmers and Horizons.

"Around 125km of riparian fencing has been put in place over the past 10 years and around 1 million trees have been planted. Almost 400ha of riparian land has been retired."

In addition to this array of land-based remedial work, Horizons has worked with Ruapehu District Council to upgrade the Waiouru and Ohakune wastewater treatment plants to significantly reduce the bacteria load of their discharges.

"The Waiouru plant alone has reduced E. coli [significantly]. Horizons has also increased monitoring of dairy farm effluent discharge to land consents for the catchment.

"The success of the Whangaehu River's improved E. coli trend is definitely one to be shared with landowners, ratepayers and the District Council."

Mr Gordon said it's pleasing to note that work will continue in the catchment due to central government funding.

"A recent application to the Freshwater Improvement Fund has seen the Ngā Wai Ora o te Whangaehu Freshwater Improvement Project receive $590,000. This will be part of the $1.68 million that is planned to be spent in the catchment on initiatives delivered by Horizons, Ngati Rangi and landowners."

The Whangaehu River award is the fifth Morgan Foundation award for the Manawatu-Whanganui Region. Previous awards have gone to the Oroua and Makuri rivers and Mangapapa Stream.

"While these numbers are worth celebrating we know there is still much work to be done. We believe that with a combination of both regulatory and non-regulatory methods, and by everyone working together, we will continue to see improving trends across the Region."