Agriculture and freshwater

Measures required to address non-point source discharges from agriculture comprise of three categories: reduction at source, interception of pollutants on land, and interception or processing of pollutants in water. ⁴⁹¹⁷

Specific farming activities are now subject to controls under the National Environmental Standards for Freshwater (NESF).  To qualify as a permitted activity under the NESF activities need to meet the relevant permitted activity conditions, some of which detail specific management measures that must be adopted.  Where the NESF requites a farming activity to apply for resource consent, then the measures discussed below provide an example of the measures an applicant might look to adopt as part of its consent application.  The NESF is discussed here.  Stock management is also controlled by the regulations which are discussed here.

Animal effluent can enter waterways either directly from animals which have access to water bodies, or indirectly as a result of effluent being transported from the land. Measures to reduce this problem include: ⁴⁹¹⁸

• Ensuring that stocking levels are within the carrying capacity of the catchment;
• Preventing stock from accessing waterways and riparian areas through adequate and well-maintained fencing;
• Keeping stock off water-logged soil and avoiding soil treading and pugging. This could include the use of feed pads during winter;
• Restoring and maintaining well-vegetated wetlands, seepage areas, bogs and filter strips;
• Use of adequate treatment systems for effluent from dairy sheds including ponds and wetland systems; and
• Ensuring that land irrigation of treated effluent does not exceed the capacity of the application area to absorb contaminants.

Fertiliser and sediment can also enter waterways directly or through ground seepage and soil erosion. Measures to reduce this problem include:

• Ensuring that fertiliser application levels are within the carrying capacity of the catchment;
• Maintaining well vegetated riparian areas;
• Avoiding fertiliser applications when rain is likely or when the water table is high;
• Keeping animals away from stream banks and wetlands;
• Avoiding overgrazing, especially in winter, which can exacerbate soil erosion;
• Constructing sediment ponds in areas where there is significant run-off;
• Constructing farm roads and tracks on stable low-gradient sites and including frequent cut-off channels;
• Constructing bridges and culverts at frequently used river crossings; and
• Minimising cultivation of soil especially in erosion prone areas.

The preparation and implementation of farm environmental management plans and nutrient budgets can enable the range of environmental impacts from a single farming operation to be identified and managed. However, the adoption of best practice farm management approaches at the individual farm level, will not necessarily be sufficient to reduce the impacts of farming activity at a catchment level, so that they are within the environmental carrying capacity of the catchment.

Some farms are likely to shortly be required to have a freshwater farm management plan.  The purpose of these plans is to “better control the adverse effects of farming on freshwater and freshwater ecosystems within specified districts, regions, or parts of New Zealand through the use of certified freshwater farm plans”. ⁵²⁷²

Last updated at 11:56AM on August 24, 2021