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2021 Hutton Medal: How contaminants move from land into water

Professor Richard McDowell FRSNZ, AgResearch and Lincoln University, has been been awarded the Hutton Medal by Royal Society Te Apārangi for his outstanding contributions to the knowledge of contaminant loses from land to water and informing environmental policy.

The Hutton Medal is awarded for significantly advancing understanding in the animal, earth or plant sciences.

Professor Rich McDowell is a land and water scientist who has made a major contribution to the scientific understanding of contaminant losses from land to water. He is best known firstly for showing how contaminants are lost from land and into water, and secondly how to manage land to mitigate losses. He has applied this knowledge to inform policy, making an immense contribution to the strategies used in New Zealand and overseas for mitigation of contaminant losses to water.

Rich studies how soils can be managed for environmental and economic benefit. He has led multiple research programmes to:

  • Provide advice on best practice farm management and inform policy to improve water quality.
  • Develop tools and practices for the management and mitigation of contaminant losses at multiple scales.
  • Improve understanding of contaminant (faecal microbes, sediment and nutrients, especially phosphorus) losses from land to water.

His work {> 230 journal articles) has been cited many thousands of times (Scopus H factor 49) and has formed the basis of public policy and guidelines for primary sector land good management.

In showing how contaminants move, he developed the concept of environmental phosphorus thresholds, where soils cannot retain added phosphorus and become leaky.

He also helped develop the theory about critical source areas on farms and catchments, highlighting that most contaminants come from small areas of a farm or catchment. This theory then helped to develop practical methods to reduce contaminant losses by targeting critical source areas with remedial action and research showed that targeting critical source areas with remedial action was up to 7-fold more cost-effective than an untargeted approach.

Soil-specific thresholds have been used in many US states in policy since the early 2000s, while critical source areas are now mentioned in more than 70 policy documents (Regional and Central Government) and industry guidelines in New Zealand and overseas. Rich’s expertise was also used to help redevelop the Australian and New Zealand Water Quality Guidelines in 2018.

Recent research by Rich and colleagues has identified dairy effluent areas on free draining stony soils (that are typical on Canterbury dairy farms) as critical source areas for phosphorus leaching loss into groundwater. This is an important discovery because it makes it possible to treat the effluent to reduce the risk of phosphorus leaching from free draining stony soils.

In providing solutions to manage land, he and colleagues have developed many of the strategies available in New Zealand to mitigate contaminant losses to water. These form the backbone of many farm environment plan systems and will be widely used when plans become mandatory for all New Zealand farmers.

Rich incorporated many of these strategies into revisions of farm management software OVERSEER in the 2010s, and within the first tool to spatially quantify and manage losses – MitAgator, released by Ballance Agri-Nutrients in 2019.

He has played an active role in informing and questioning policy. For example, he showed that 77% of contaminant loads come from small, unfenced streams, meaning that policy to only fence large streams wouldn’t improve water quality. This analysis was voted the best paper in the Journal of Environmental Quality 2017-2019.

Outside of academia, Rich is Chief Scientist for the Our Land and Water National Science Challenge helping to lead a team of approximately 200 scientists in improving our land and water quality.

Rich is also a Professor at Lincoln University. His research career began at Cambridge University, where he was invited to study; he then worked at the United States Department of Agriculture before returning home to New Zealand.

He has received numerous international and New Zealand awards for his contributions to land and water science, including the USDA-ARS distinctions for outstanding research, OECD fellowships and the New Zealand Society of Soil Science’s top awards: the Norman Taylor and ML Leamy awards in recognition of contributions to New Zealand soil science and impact. He is a Fellow of the New Zealand Society of Soil Science and Royal Society Te Apārangi. He is also Editor-in-chief of the Journal of the Royal Society of New Zealand. 

Rich feels honoured and humbled to receive the Hutton Medal, but is quick to acknowledge the contribution from friends and colleagues who have provided support and advice throughout his career. He also acknowledges the hard work of New Zealand farmers who have long relied on and used science in their daily business. Implementing science is needed now more than ever if we are to collectively meet our aspirations for healthy food and healthy land, water and air.


The Hutton Medal is awarded annually for animal sciences, earth sciences, or plant sciences, to the researcher who, working within New Zealand, has significantly advanced understanding through work of outstanding scientific or technological merit.


To Richard William McDowell for outstanding contributions to the knowledge of contaminant losses from land to water, and informing farm management and environmental policy.