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Published on: July 24, 2016
Water quality in headwater catchments with deer wallows
1AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand. richard.mcdowell@agresearch.co.nz
Journal of Environmental Quality
|July 20, 2007
Summary
Red deer wallowing in New Zealand headwater streams significantly increases contaminant losses, particularly phosphorus and sediment. Management should focus on preventing wallowing to protect water quality.
Area of Science:
- Environmental Science
- Agricultural Science
- Water Quality Management
Background:
- Pastoral farming of red deer (Cervus elaphus) is prevalent in New Zealand.
- Red deer exhibit natural behaviors, including seeking water and creating wallows, often connected to waterways in headwater catchments.
- These wallows are perceived as potential sources of significant contaminant runoff.
Purpose of the Study:
- To quantify the contribution of red deer wallows to contaminant loads in three New Zealand headwater catchments.
- To assess the impact of wallowing on nitrogen, phosphorus, suspended sediment, and E. coli levels in waterways.
Main Methods:
- Monthly sampling of base flow and storm flow over a defined period.
- Analysis of water samples for nitrogen (N) and phosphorus (P) species, suspended sediment (SS), and fecal indicator bacteria (E. coli).
- Comparison of contaminant loads with established water quality guidelines and loads from other pastoral catchments.
Main Results:
- Median concentrations of measured contaminants frequently exceeded New Zealand's water quality guidelines for lowland areas and contact recreation.
- Loads of phosphorus (up to 3 kg P ha⁻¹) and suspended sediment (up to 4.5 Mg ha⁻¹) surpassed those reported for other New Zealand pastoral catchments.
- Contaminant losses were higher during storm flow than base flow, with the majority occurring when deer were actively wallowing and connected to waterways.
Conclusions:
- Red deer wallowing significantly contributes to contaminant losses in headwater catchments.
- Management strategies should prioritize discouraging wallowing and disconnecting wallows from waterways to mitigate environmental impact.
- Addressing deer wallowing is crucial for improving water quality in affected pastoral regions.
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