Stock exclusion from waterways
The exclusion of livestock from waterways, provides significant benefits for the conservation and sustainability of our natural ecosystems.
One of the primary environmental benefits lies in the substantial improvement of water quality, as preventing livestock from contaminating water sources with faecal matter, pathogens, and sediment reduces the risk of waterborne diseases and ensures cleaner, safer water for both humans and wildlife.
The exclusion of livestock serves as a potent tool in the prevention of erosion along riverbanks, safeguarding the stability of these critical areas and preventing sediment runoff that can degrade water quality. Fencing waterways contributes significantly to habitat conservation by preserving and restoring vital riparian zones, which are essential for diverse species of invertebrates, fish and birds, both as primary habitat and as wildlife corridors.
Fencing is an expensive mitigation strategy in the short term. However, when implemented well and with good stock management practices, fencing effectively excludes livestock from waterways for many years after it is erected. Over a lifespan of 20–30 years the cost-effectiveness of fencing improves, and can sustain good water quality for decades*.
Compliance with environmental regulations also underscores the necessity of stock exclusion, promoting a harmonious coexistence between agriculture and ecological preservation. The exclusion of livestock from waterways represents an indispensable strategy for maintaining the health and sustainability of our water ecosystems, underpinning the broader goals of responsible land and water management.
Within Aotearoa New Zealand, stock must be excluded from rivers, lakes and wetlands within in certain timeframes depending on the type of stock, slope and intensity of grazing according to the Resource Management (Stock Exclusion) Regulations 2020. Excluding stock from waterways can reduce the negative harm caused to mahinga kai values and negative effects on stream bank stabilisation, erosion, and water quality.
Steeply sloping shallow streams 1m or less wide are exempt from these regulations. However, research
indicates an average of 77% of the national contaminant load comes from exempt streams in flat catchments dominated by pasture. When looking at on-farm mitigations to reduce contaminant loads from these streams, consider that:
- Exempt streams are mostly headwaters. Not excluding stock from these waterways can make it more difficult for land stewards downstream to improve water quality.
- To substantially reduce contaminant losses to exempt streams, mitigations such as stock exclusion are needed, particularly on farms where fencing larger streams is not effective.
- Where stock exclusion is prohibitively expensive, less costly strategies should be considered, such as reducing fertiliser rates, using less water-soluble forms of fertiliser, and grazing gullies later in the winter. Such measures can also act as a backstop if fencing fails to exclude stock.
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