Deer have a natural instinct to seek water and wet areas and wallow in them . Both sexes wallow, but stags wallow more intensively in the rut. Wallowing is thought to benefit deer through tick control, hair removal, cooling and social interaction. For more, see wallowing.

Environmental effects of wallowing
The environmental effects of wallowing can range from negligible to significant depending on the location of the wallows. Wallows that have ‘connectivity’ with waterways (either permanent or ephemeral) will result in significant quantities of suspended solids, phosphorus, nitrogen and coliforms getting transported off the farm in active or ephemeral water flows. These ‘connected wallows’ are classified as ‘Critical Source Areas’ and are a high risk to water quality.  

Evidence from AgResearch (McDowell, 2009) shows that adopting a practice of ‘safe’ wallows and removing high risk wallow area results in significant reductions of suspended sediment (soil loss), total phosphorous (P) and bacterial loads, Escherichia coli (E. coli), to waterways.  Consequently, the positioning of safe wallows in combination with fencing and riparian planting of waterways, wet areas and existing wallows is recommended as a strategy to mitigate water quality problems associated with deer wallowing.

Environmentally safe wallows

  • Farmers can indulge normal deer wallowing behaviour in low risk locations and avoid or remedy the negative water quality problems associated with the position of some deer wallows.  Evironmentally safe wallows are located away from-
  •  permanent streams or in wetland areas that connect to streams; and
  • ephemeral flood pathways that connect to streams during rainstorm events.

Wallowing can also occur in and around the water troughs on deer farms. Provided the troughs are not located in storm water flow paths (ephemerals), this is not an environmental issue but can be minimized with good water trough placement and maintenance. Refer to recommendations for water troughs Pg 18 of the Landcare Manual.    

High Risk Wallows
Existing high risk wallows connected to waterways should be eliminated by drainage and/or in-filling, cultivation, or fencing off and planting. For tips on repair of old wallow holes and trough protection,  refer to Land Care Manual p 19  To ensure high risk wallows are removed, itemize and prioritise these in your LEP Level 2 works programme or your Level 3 response plan with a realistic completion schedule.

Show me the science

R.W. McDowell, M.S. Srinivasan (2009). Identifying critical source areas for water quality: 2. Validating the approach for phosphorus and sediment losses in grazed headwater catchments. Journal of Hydrology 379: 68–80.

R. W. McDowell (2009). The use of safe wallows to improve water quality in deer farmed catchments. New Zealand Journal of Agricultural Research 52:1, 81-90.