Bacterial levels in water a challenge
Collaborative catchment project aims to better understand E. coli
We’ll collect water and sediment samples in the Nguturoa catchment, with the purpose of developing the model to represent what is happening across New Zealand. — Project lead and AgResearch science team leader Dr Richard Muirhead
Acollaborative project between DairyNZ, AgResearch and the Manawatu’s Nguturoa Catchment Group aims to understand, model and manage E. coli in rural waterways.
Reducing bacterial levels is a challenge in waterways in many parts of New Zealand. This multi-year project aims to understand how E. coli gets into waterways, develop strategies to reduce losses from rural land to streams, and create a model to show how on-farm mitigations could reduce E. coli losses.
The Nguturoa catchment runs from the ranges behind Linton to the Tokomaru River and down to the Manawatu River. It comprises dairy, sheep and cattle farmers and lifestyle block owners.
Working closely with farmers, DairyNZ and AgResearch will undertake research and field work to better understand E. coli pathways and processes in farming catchments.
DairyNZ general manager sustainable dairy Dr David Burger says this will mean better models can be created for developing and demonstrating options for farmers to reduce losses and help build regulatory understanding. “This project is part of DairyNZ’s ongoing work to support farmers to reduce their environmental footprint while continuing to run successful farming businesses. New strategies to reduce losses could be adopted by dairy farmers across New Zealand in areas where E. coli is an issue.”
Project lead and AgResearch science team leader Dr Richard Muirhead is one of New Zealand’s leading experts on E. coli contamination of waterways. He says a key issue with helping farmers and regional councils manage E. coli is understanding how multiple small sources of the contaminant from farms and other land uses combine to produce the concentrations measured at swimming sites downstream.
“The long-term focus of this project enables us to develop people and capabilities in catchment E. coli modelling, to help address this gap. We’ll collect water and sediment samples in the Nguturoa catchment, with the purpose of developing the model to represent what is happening across New Zealand.
“The catchment level focus is an exciting opportunity to integrate a lot of our existing farm-scale E. coli knowledge into what happens at the catchment scale, which is where water quality impacts happen,” Dr Muirhead says.
The DairyNZ team working on this project includes Craig Depree, who has nearly 25 years’ experience as a water quality scientist, and Katrina
Macintosh, whose international experience spans water quality and environmental practice change onfarm. Both Katrina and Craig have recently published research on how good farming practices have improved water quality in dairydominated catchments.
The sector remains committed to improving waterway health, while ensuring timeframes for implementing ongoing change are reasonable. Continued work includes DairyNZ-led water quality research, in collaboration with other science organisations, to identify solutions for farmers at a farm and catchment level.
“This will ensure we can prioritise actions in specific sites where they can make the most difference, and track improvement,” Dr Burger says.
Many dairy farmers are also restoring riparian margins (the strips of land that run alongside a waterway) and implementing good farming practices that can significantly reduce contaminant losses to waterways.