Principal scientist Murray Close is a member of ESR’s Water group and leads its Groundwater team.
With over 44 years’ experience in groundwater research, Murray is an expert in groundwater conditions and processes in New Zealand.
Murray has served as programme leader on a number of major research programmes, including the Enhanced Mitigation of Nitrate in Groundwater research programme and the Groundwater Modelling of Contaminant Transport project, and coordinates the National Survey of Pesticides in Groundwater every four years.
The Enhanced Mitigation of Nitrate in Groundwater project is developing new methods for inducing denitrification in groundwater systems, in particular oxic, fast flowing, heterogeneous alluvial gravel aquifers. His team is developing innovative approaches such as denitrifying Permeable Reactive Barriers. These are being coupled with aquifer characterisation using advanced shallow depth geophysics, DNA tracers and groundwater microbial community analysis to enable the effective design, delivery and implementation of these mitigation tools. The use of denitrifying bioreactors to treat nitrate from artificial drains is also being trialled.
Past research has ranged from developing a method for predicting reduced groundwater zones, to assessing the assimilative capacity of the groundwater with respect to different contaminants, to developing tools for testing water quality, to working on an international project looking at measuring denitrification rates in groundwater, to developing a new method to study the structure of alluvial gravel aquifers.
“Most of the research I am involved in has practical applications for local government, industry and communities” Murray says.
“Regional councils have the responsibility to implement the government’s freshwater reforms which seek to balance the goals of ‘maintaining or enhancing water quality’ and ‘increasing production from agriculture’. Knowledge of the assimilative capacity of the groundwater system is crucial to estimating loads of contaminants entering into river and lakes.”
“It is important for us to develop an understanding of the whole subsurface system so that we predict what will happen as contaminants leave the soil layer, where they are transported, and what processes will affect them. As part of this, we are working on ways to measure and model land-use impacts on groundwater quality,” he says.
Areas of expertise and interest:
- Modelling the transport and fate of groundwater contaminants, such as nitrate, organic compounds, heavy metals, and microorganisms
- Land use effects on groundwater quality
- National and regional assessments of groundwater quality
- Unsaturated zone processes affecting groundwater contamination
- Leaching of pesticides and pesticide contamination of groundwater systems
- Characterising the structural and hydraulic properties of groundwater and vadose zone systems
- Investigation of groundwater ecosystems, including biofilms and stygofauna
- Remediation and removal of nitrate in groundwater systems