DWER Department of Water and Environmental Regulation EP Act means the Environmental Protection Act 1986 (WA). License The existing License L was issued under Part V, Division 3 of the EP Act and in force prior to the commencement of, and during, this Work Approval. Premises refers to the Work Approval Holder specified on the front of this Decision Report.
Risk Event As described in the Guidance Statement: Risk Assessment RIWI Water and Irrigation Rights Act 1914. The applicant submitted an application for approval of works on 29 June 2018 (Application) to construct an evaporation pond, six deep water shelters waste and a spilled load. The works will increase the pig's design capacity from 3,840 SPU to 5,742 SPU (including piglets).
This Decision Report documents the Delegated Application Officer's assessment and determination in accordance with the DWER Regulatory Framework. The scope of the risk assessment includes potential impacts from emissions and discharges during the construction and operation phases.
Application details
The permit conditions allow the purification of wastewater from pigsty in wastewater treatment and evaporation ponds; removal of treated wastewater by reuse within the pig house for flushing, on-site irrigation or evaporation, and removal of solids by dispersion to land within the premises. The applicant has applied for planning permission for the construction of six deep litter shelters, one loading shed and the construction of a high density polyethylene (HDPE) lined evaporation pond. During a site visit to the property on October 10, 2019, the applicant informed DWER officials that six disused wastewater basins will be decommissioned.
Infrastructure
A new conventional loading shed to be connected to the current drainage and ponds, and. The existing and proposed infrastructure in terms of Category 2 activities at the facility is detailed in Table 4 and Table 5, respectively. 4 Solid waste storage area – Screened and concrete-lined solid waste storage area with drainage return system.
5 2 x Optional ponds (clay-lined) – referred to an optional pond and evaporation pond on Existing permit.
Operational aspects
The applicant performed water balance calculations to assess the capacity of the proposed system, including the two existing optional ponds and the proposed evaporation pond, to manage the amount of waste water from the pig farm. In addition, the construction of the evaporation pond will remove the requirement for the discharge of purified water through irrigation at the site. Peel Pork Piggery is located between Mandurah and Bunbury and this averaging of the two stations is considered appropriate for the water balance calculations.
The water balance used the adjusted annual 90th percentile rainfall from the average of Bunbury and Mandurah rainfall (BOM, Mandurah: Station 9977; Bunbury: Station 9965). In the unlikely event that two consecutive years of high rainfall in the 90th percentile occurred, the losses in the construction of the new evaporation pond would allow all water to be held on site without penetrating the 0.3 m (300 mm) freeboard in the proposed evaporation pond. The premises are located in the Peel-Harvey EPP and have been identified in the Hydrological and nutrient modeling of the Peel Harvey Catchment – Water Science Technical Series Report (DoW, 2011) and Agriculture Futures: Potential rural area uses on the Palusplain (DAFWA) 2012) as being in a high-risk nutrient export area that requires a significant reduction in phosphorus loading.
Peel-Harvey System Rivers and Estuary Water Quality Improvement Plan (EPA, 2008). This is based on the condition of the wells, gaps in water quality and poor location of the sampling sites.
Other relevant approvals
Consider four new monitoring boreholes consisting of two seasonal groundwater piezometers located and two surface aquifer boreholes located at two locations near major infrastructure.
Part V of the EP Act
Environmental siting context
Residential and sensitive premises
- Specified ecosystems
- Groundwater and water sources
- Soil type
- Meteorology
- Determination of emission, pathway and receptor
- Consequence and likelihood of risk events
- Acceptability and treatment of Risk Event
- Risk Assessment – Risk of loss of containment and seepage
- Risk Assessment – Application of solids to land
- Summary of acceptability and treatment of Risk Events
- Works Approval Controls
All rural residential properties and the urban area or Yarloop are outside the minimum separation distance and comply with NEIPG 2018 standards. Swan Coastal Plain Wetlands The Resource Enhancement Wetland is located 25m west of the existing pig buildings. Peel Harvey EPP The entire site lies within the boundaries of the Peel Harvey EPP, within the Harvey River catchment.
Five boreholes are located within 1.5 km of the Site boundary (based on available DWER Geocortex dataset – Compass Groundwater Sites. The nearest weather station to the Site is located in Wokalup approximately 16 km south of the Site. The Applicant has an average of the Site use Bunbury and Mandurah weather data for modeling purposes.
The Delegated Officer is of the opinion that the separation distance between the Premises and the nearest sensitive receptors is sufficiently large for a low probability of adverse impact from noise or dust emissions from the operation of the intensive pig farm. DWER will undertake an assessment of the consequence and likelihood of the Risk Event in accordance with Table 16 below. The following criteria were used to determine the probability of the risk event.
Furthermore, in the event of high rainfall, the palusplain wetland system may flood part of the piggery. The Meredith Brook catchment is part of the Peel Harvey EPP area where emission reductions have been targeted for the Harvey River, which includes the Meredith Brook catchment. The Harvey River catchment has a maximum total phosphorus export rate of 0.47 kg/ha/year, as specified in DWER's report Hydrological and Nutrient Modeling of the Peel-Harvey catchment (DoW, 2011).
Pig animal solids are only applied to areas of the site where the soil has been modified by the addition of bauxite residue (red mud). Therefore, the Delegated Officer considers that the current risk event of spills to land as a result of the distribution of the solid waste is unlikely to occur in most circumstances and considers the likelihood to be Unlikely. MB7 Shallow drill screen interval of 3-6mbgl directly behind the western edge of the 6 new pig shelters.
Removal of existing irrigation needs as irrigation will cease with the operation of the new evaporation pond. DWER officials who visited the site on September 30, 2018 observed surface expression or flooding of areas of the premises due to recent winter rainfall.
Site Plans, maps and drawings
Monitoring data
4 – Australian and New Zealand Guidelines for Fresh and Marine Water Quality – Volume 1, October 2000, Australian and New Zealand Environment and Conservation Council and Agricultural and Resource Management Council of Australia and New Zealand (ANZECC Guidelines) – Freshwater trigger value for slightly – moderately disturbed ecosystems.
Key documents
