Saturday, 30 June 2018 08:55

Five-year project to measure contaminant losses

Written by 
Aslan Wright-Stow. Aslan Wright-Stow.

Riparian buffers and constructed wetlands reduce contaminant loss to waterbodies, but by how much?

DairyNZ water quality specialist Aslan Wright-Stow explains a national project aimed at finding out, and why this matters as regional limit setting ramps up.

Many landowners are in the process of identifying and implementing ways to reduce contaminant loss to waterbodies, which are increasingly required by regional limit-setting processes. 

Constructed wetlands and riparian buffers are at the forefront of the options available, but we need to know how they perform in all landscape settings so we can optimise their performance, and as a farmer your efforts to reduce contaminants are rewarded in farm nutrient/ contaminant budgets.

The project is jointly funded by DairyNZ (through the farmer levy), the National Institute of Water and Atmospheric Research (NIWA) and regional councils. It’s taking place over five years, beginning by developing provisional performance and design guidelines for immediate use, based on current scientific understanding.

At the same time, we’ll design, establish and monitor a range of riparian buffer and constructed wetland systems across New Zealand to quantify and compare performance in different landscape and climate settings.

Wetlands and riparian buffers

Monitoring the constructed wetlands is a relatively straightforward exercise comparing the quality of water entering and exiting the wetland to determine contaminant loss1. The aim of the riparian monitoring is to find out if having wider buffers at locations where runoff is more strongly focused (‘critical source areas’) will improve flow and contaminant filtering. In principle it should; however, testing this at catchment scale has so far not been done here or overseas.

We’ll identify and compare suitable paired catchments throughout the country, each pair having a standard fixed-width buffer and a variable-width buffer (made wider at critical source areas and narrower where overland runoff is less important). We’ll be trying to find out how optimal water quality return relates to cost, time and farm productivity.

While mainly focused on reducing primary water quality contaminants (sediment, nitrogen, phosphorus and faecal microbes), this project will also provide new information on flow buffering, biodiversity and habitat enhancement. It’ll identify options for addressing issues related to climate change as well (e.g. providing stream shading, managing water temperatures).

The project’s results will enable us to guide farmers’ water quality initiatives so you can meet regional limits, improve water quality on your farm and get greater certainty of performance. 

It will make your efforts more cost-effective, but also ensure your efforts are rewarded by authorities in nutrient budgets. Our results will also identify what works where and on what scale, so water quality efforts can be tailored to suit individual and regional situations. Overall, the research project will quantify the performance of riparian buffers and constructed wetlands to ensure farmers are recognised for their water quality efforts.

• This article was originally published in Inside Dairy May 2018

More like this

Featured

Dr Mike Joy says sorry, escapes censure

Academic Dr Mike Joy and his employer, Victoria University of Wellington have apologised for his comments suggesting that dairy industry CEOs should be hanged for contributing towards nitrate poisoning of waterways.

People-first philosophy pays off

The team meeting at the Culverden Hotel was relaxed and open, despite being in the middle of calving when stress levels are at peak levels, especially in bitterly cold and wet conditions like today.

Farmer anger over Joy's social media post

A comment by outspoken academic Dr Mike Joy suggesting that dairy industry leaders should be hanged for nitrate contamination of drinking/groundwater has enraged farmers.

From Nelson to Dairy Research: Amy Toughey’s Journey

Driven by a lifelong passion for animals, Amy Toughey's journey from juggling three jobs with full-time study to working on cutting-edge dairy research trials shows what happens when hard work meets opportunity - and she's only just getting started.

National

Machinery & Products

JDLink Boost for NZ farms

Connectivity is widely recognised as one of the biggest challenges facing farmers, but it is now being overcome through the…

New generation Defender HD11

The all-new 2026 Can-Am Defender HD11 looks likely to raise the bar in the highly competitive side-by-side category.

» Latest Print Issues Online

Milking It

Buttery prize

OPINION: Westland Milk may have won the contract to supply butter to Costco NZ but Open Country Dairy is having…

Gene Bill rumours

OPINION: The Gene Technology Bill has divided the farming community with strong arguments on both the pros and cons of…

» Connect with Dairy News

» eNewsletter

Subscribe to our weekly newsletter