Assessing environmental compliance of ponding and seepage from dairy feed pads and stand-off areas

TR 2012/03
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Report: TR 2012/03

Author: T Fenton (Alchemists Ltd)

Abstract

Wintering systems are increasingly being used in the Waikato to provide improved stock and feed management, protect soils, manage pasture, and to reduce contaminant losses during winter periods.  Many of these systems include animal shelters or feed and stand-off pads are well managed and follow current best practice. These systems actively manage and treat the effluent that accumulates during their use.

Some Waikato dairy farm feed pads and stand-off areas do not actively manage the effluent generated by their use and this potentially raise issues for contamination of waterways. They often use absorbent material, such as post peelings or saw dust, to contain some of the effluent on pad but these still generate effluent runoff or drainage which can enter waterways causing contamination.  Due to this potential for contaminant loss Waikato Regional Council wants to know what criteria consenting staff could use to assess whether or not the intensity of use or any effluent ponding was likely to pose a significant non-compliance issue.

The scope of this report is limited to the potential impact of ponding and seepage from dairy feed and stand-off pads which do not use defined best management practices (BMPs) of sealed pads, capture, storage and effluent spreading.

The purpose of this report is to provide two key outcomes:

  • To evaluate the potential scale of impacts of ponding and seepage from feed pads and stand-off pads on the environment by:
    • a comprehensive literature review of nutrient, faecal microbes and organic contaminant losses from feed pads or stand-off areas and the risk this poses to water quality
    • assessment of the amount of nutrients and faecal microbial loss that could potentially enter a waterway or drain to groundwater from a feed pad or stand-off area
    • evaluating the significance of this in proportion to losses from the whole farm, the cumulative significance of losses from other farm activities and multiple farms within a catchment.
  • Provide a risk assessment of these activities and provides field guidelines/criteria to assist enforcement officers in determining whether seepage or ponding from a particular dairy stand-off area or feed pad would be a significant non-compliance issue. 

To assist the report outcomes context is also provided on the use of pad systems, drivers of regional variability and the assessment and management of risk.

Assessing environmental compliance of ponding and seepage from dairy feed pads and stand-off areas [PDF, 685 KB]

Contents
  Executive summary 3
1 Background 6
1.1 Purpose of report 6
1.2 Feed pads and stand-off pads - overview of systems 7
1.3 Use of pad systems 10
2 Contaminant losses from pad systems - review of literature 11
3 Risk assessment of pad systems 16
3.1 Using a risk management approach 16
3.2 Risk assessment within farm systems 18
3.2.1 Farm scale contaminant losses 18
3.2.2 Benefits of wintering systems 20
3.3 Risk assessment within feed and standoff systems 21
3.3.1 Potential effluent quality and loads 22
3.3.2 Potential for surface water contamination 25
3.3.3 Runoff risk - key drivers 26
3.3.4 Potential for ground water contamination 27
3.3.5 Leaching risk - key drivers 30
3.3.6 Solids management 30
3.3.7 Summary of potential contaminant losses 31
3.3.8 Summary of environmental risks 32
4 Field evaluation of permitted activity rule - guidelines and key criteria 34
4.1 Evaluation practices - overview 34
4.2 Assessment of compliance 35
4.3 Assessment of risk 35
4.4 Identifying opportunities 36
4.5 Evaluation of different feed and stand-off pad systems 36
4.5.1 Feed pads and stand-off pads - Waikato Regional Plan Permitted Activity Rule 3.5.5.2 37
  Appendix 1 - Waikato Regional Plan Permitted Activity Rules - Section 3.5 Discharges 41
  Appendix 2 - Classification guidelines used to assess compliance status 44