Report: TR 2012/03
Author: T Fenton (Alchemists Ltd)
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 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.
|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|
|3.3.7||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|
|4.5||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 22.214.171.124||37|
|Appendix 1 - Waikato Regional Plan Permitted Activity Rules - Section 3.5 Discharges||41|
|Appendix 2 - Classification guidelines used to assess compliance status||44|