Linking Legacies to Wai
Accounting for lag times and natural concentrations of contaminants in groundwater
What Are We Doing?
The decisions farmers make today on land can take many years to be reflected in the health of water in our rivers and groundwater. In the past, this ‘lag time’ contributed to a lack of understanding of the intrinsic connection between wai and whenua.
This research will demonstrate the effects of agriculture on our freshwater over the past 170 years and will predict how quickly future land-use decisions will restore the health of degraded water. The project aims to use this knowledge to grow understanding among land stewards of the connection between whenua and wai.
This project will have a focus on groundwater. It will find out how long it takes for changes in land use or intensity to be reflected in nitrate concentrations in groundwater.
How Can The Research Be Used?
- The lag time between land-use changes (largely intensification) and the increase in the load of nitrate in streams and rivers has been quantified as 4.5 years on average for 77 catchments that capture about 50% of Aotearoa’s agricultural activity.
- This research will help set realistic timeframes to decrease nitrate concentrations in groundwater, and streams and rivers. If nitrate is not decreasing quickly enough, Councils will have evidence to take further action.
- Māori, government (central and local) and peak industry bodies were asked to prioritise land uses, land practices and past and future years to be examined.
Have a Question?
We are happy to answer any questions about this research and how it can be used.
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