Research supporting good water management
Measuring fine sediment abundance using plastic viewer and comparator chart.
Case study 7
The September 2010 report of the Land and Water Forum identified the catchment as ‘in most cases the best physical unit for management of waterways’ concluding that science and management effort should be directed towards integrated catchment management initiatives. Water management achievements from ICM research addressed many of the recommendations of the forum report.
In the water allocation arena, research with Cawthron and GNS has shown how groundwater pumping has consequences for trout survival. Gravel aquifers across New Zealand lose or gain water from nearby rivers. Therefore when councils set allocation limits for pumping water from aquifers they need to base those limits, among other things, on desirable flow regimes in those rivers for maintaining fisheries and their habitats.
ICM research on groundwater-surface water connections focused on a 15-km section of the Upper Motueka River that has recently experienced a substantial increase in demand for water for dairying and horticultural development. Here, upwelling of cool groundwater potentially provides an important refuge for temperature sensitive species during the summer, such as the brown trout that support a nationally important fishery in the Motueka River.
A groundwater-surface water model was developed to describe the patterns of upwelling and downwelling along the Motueka Valley and to determine the likely influence of groundwater abstraction. Temperature loggers deployed over 18 months showed water temperatures ranging from 4°C to 23.7°C. Maximum daily temperatures regularly exceeded the upper limit for feeding by brown trout (19°C) during summer and autumn. River reaches receiving groundwater inflow (gaining reaches) often had lower maximum temperatures during periods of low flow, pointing to the need to maintain some groundwater recharge if the trout population is to be protected during low flow periods.
This type of biophysical science is needed to underpin water policy developed by regional councils. But as noted by the Land & Water Forum, research is also needed on social and economic factors which support effective policy. Water management is as much a political process as a technical one.
ICM research tackled questions of new policy approaches that could improve outcomes from water allocation. Moving beyond the Motueka, we also identified 20 attributes for achieving good water governance in New Zealand, based on stakeholder interviews about five RMA catchment management planning and implementation processes from other South Island catchments. Many of the resulting priorities are addressed in the Land and Water Forum report and in current MAF and MfE initiatives:
- An expanded role for stakeholder Water Management Committees (WMCs) in low flow management, achievement of water quality and catchment management targets
- Making Water Permits more Transferable
- Clearer definition and quantification of water users’ Security of Supply Support for Water Metering for Water Permit Holders
- Cost sharing for water planning and management between users and the community benefitting from water use
- Alternatives to the current ‘first-in, first-served’ allocation method particularly for resources approaching fully allocated.
An Integrated Catchment Management (ICM) perspective ranging from technical research across to governance and collaborative processes seems essential to help better manage New Zealand’s land and water resources into the future.
Andrew Fenemor
Roger Young
Cawthron Institute, Nelson
Roger.Young@cawthron.org.nz