Land use and water quality
Scott Bartlam (Landcare Research) with Waikato-Tainui tribal members and Waikato Raupatu River Trust Wetland Scholarship recipients, Joshua Ormsby (Puurekireki Marae and Jonathan Brown (Maurea Marae) discussing the colour of the harakeke Phormium tenax leaf edge, which was traditionally thought to be an indicator of the quality of the flax fibre by weavers.
Land and water are inseparable elements of our natural environment. What happens with our water – both quality and availability – generally starts with what’s happening on the land.
Good land use may contain demands for irrigation within environmental limits; it may avoid excess nutrients that end up in groundwater or streams; it may reduce sediment from erosion and reduce the chance of flooding; and it may moderate the availability of water further down a catchment. All of these interactions mean that when we try to manage water quality and availability we have to look carefully at the land uses. Good land-use practice can address many of the challenges we face with water.
This issue of Discovery focuses largely on the work of Landcare Research at the interface between land and water at a range of spatial scales from paddock through to national, where our knowledge and tools can be applied to developing policy and implementing management actions in the field.
At the national scale, the launch of the National Land Resource Centre, fills a significant gap in making soils and land information and services more readily available, through a single portal regardless of its source. The NLRC is a collaboration between providers, with informatics technology and leadership from Landcare Research.
At the regional scale we describe how the New Zealand Forest and Agriculture Regional Model (NZ-FARM), developed by Landcare Research, is being used to model the benefits of water storage, water quality caps, good management practices, tax and trading systems, and land-use options. Importantly, NZ-FARM links economic and environmental aspects of policy challenges.
At the regional down to farm scales our collaborative work with the Aquifer-Sim model and S-map (spatial soils information) has improved the ability of land managers to assess the impacts of land use on leaching and water quality. The project has contributed to Environment Canterbury’s work on land use and water quality and thinking around nitrate limits.
At the farm scale Landcare Research’s work on variable-rate irrigation has shown that water savings of up to 36% can be achieved without impact on yields, making water available for other uses on-farm. This collaboration with Precision Irrigation-Lindsay Corporation, Streat Instruments, Hydroservices and leading farmers uses detailed soil mapping information to program the variable rate irrigation equipment.
Wetlands provide vital ecosystem services – cultural, aesthetic and functional, cleaning up waterways and storing carbon – but more than 90% of pre-settlement New Zealand’s wetlands have been lost. We describe the exciting developments in our wetland restoration programme; and our cover photo shows two Waikato-Tainui trainees who have been engaged in the programme.
We also highlight our involvement in the Treaty of Waitangi settlement for the Tūhoe iwi. This breaks new ground internationally, taking Te Urewera National Park out of the park network and putting it under its own legislation and governance by Tūhoe and government. Landcare Research has been proud to work with Tūhoe, helping to engage stakeholders in the park and explore governance models.