Community and Education news

7 November 2019

New Zealand’s most improved river announced amongst winners at River Awards

Environment Southland’s Waihopai River took out the Supreme Award for Most Improved River at the New Zealand River Awards 2019.

The annual Awards are a celebration of rivers and catchments that are making major efforts to improve river health. They provide an opportunity to learn from those communities, councils, iwi and landowners who are working hard to enhance their waterways.

The ‘Most Improved River Award’ is made for a river or stream showing the greatest improvement in a pre-determined measure of river ecosystem health at a specific monitoring site. The award is based on the most improved trend observed in a selected water quality parameter over the past 10 years, rather than on its current state.

This year, the judges shifted their focus from a single indicator to a measure that combines E. coli levels and the Macroinvertebrate Community Index as the basis for determining improvement. This change was made in response to feedback, which asked for a more holistic assessment of river ecosystem health, rather than a focus on just a single water quality indicator. Both indicators have been sampled by regional councils for more than a decade and sufficient data was available to allow for robust judging. Improvements are determined from statistical analysis of monitoring data from more than 1400 sites across New Zealand that is available from LAWA (Land, Air, Water Aotearoa).

Waihopai River, located near Invercargill, has cleaned up its act, with E. coli dropping 6.1% per annum and its Macroinvertebrate Community Index (MCI) rising 1.9% per annum over the past decade.

Waihopai River

“New Zealanders want healthy rivers, not just better water quality – a broader view is therefore necessary,” says Dr Roger Young, freshwater scientist and Coastal and Freshwater Group Manager at Cawthron Institute, and one of the New Zealand River Awards Judges.

“Indicators are used to provide information about how a waterway is functioning and to assess its overall health,” says Dr Young.

“Indicators can help to give an early warning of impending concerns, show whether conditions meet acceptable limits, and help diagnose the causes of poor health. However, a single indicator will never fulfil all these purposes.

“Ideally, we would like to complete a full river health check-up that includes indicators of biological community composition, ecosystem processes, flow regime, and physical habitat structure, as well as water quality. However, there is currently insufficient data on all these components at most monitoring sites to allow this to occur. Moving from one indicator to two indicators is a small step in the right direction.”

Although Waihopai is this year’s supreme winner, the river is by no means pristine. River health is getting better, but considerable improvement is needed to make the river swimmable and its MCI levels are still poor.

Between 2006 and 2015 a Living Streams project led by Environment Southland worked with farmers to identify issues, prepare farm environment plans, and direct funding to specific initiatives.

The combination of the Living Streams project and the upgrade of urban and industrial wastewater systems have had a marked positive impact on the health of the Waihopai River.

Going back a decade or two, Invercargill turned its back on the Waihopai and referred to it as ‘the drain’. Its flat catchment had been drained to make way for intensive farmland and in the lower reaches the river was barricaded in to protect the city from flooding. The accumulated effects of steep and eroding drainage banks, nutrient losses from farming, stormwater discharges contaminated with sewage and other industrial contaminants led to a river in a poor state.

Permanent riparian fencing and some vegetation prevents overland runoff reaching the watercourse

During the past ten years the regional and city councils, farmers, industry, and the local community have joined forces to improve water quality and river health.

Environment Southland subsidies assisted 90km of streambank fencing, extensive riparian planting, several new stock crossings and a couple of reticulated stock water systems – all helping to keep stock out of waterways.

Council encouraged good management practices such as better fertiliser application, alternative wintering grazing methods and locations, and improved effluent storage and dispersion. Several farmers identified areas of their farms that would be better as wetlands than grazing land. Community groups along the river have undertaken intensive riparian planting projects.

Riparian planting along the Waihopai

A focus on improving wastewater management has also been important. One settlement, with roughly 60 houses had, until recently, been using septic tanks, some of which leaked into the river. By 2016 the council had completed the wastewater network and houses are now starting to be connected to the city’s wastewater treatment system.

This catchment is home to an eel processing factory, a large timber mill and a meat processing plant. These factories employ several hundred workers. During the past ten years improvements have been made to the factories’ wastewater systems including connecting to the city’s network, installing a new aeration settling pond, and a constructed wetland.

These actions cumulatively mean that in addition to improving E. coli and MCI levels, other indicators are also moving in the right direction. The river shows positive water quality trends for water clarity, dissolved reactive phosphorus, ammoniacal nitrogen, total phosphorus, and turbidity.

“It’s very important to emphasise that while the River Awards celebrate improvement in river health, they are also a way of focusing attention on the work that remains to improve rivers around the country,” says Young. “Waihopai River provides a lesson about using a multi-faceted approach in the quest for a healthy river.”

In addition to identifying the most improved rivers, two other important awards were announced:

The River Story Award: for the most interesting and compelling story of an individual or community working to improve the health of a river, or rivers generally went to Tasman River in South Canterbury.

The Reo mō te Awa (River Voice) Award: for an individual who has the raised the profile of rivers through compelling public commentary went to Alison Dewes.

Read the 2019 New Zealand River Awards Judges Report here.