Agriculture and livestock: climate change adaptation case study

Reducing pollution risk to waterways and land from heavy rainfall at intensive agriculture and livestock processing facilities.

This Scenario focuses on agricultural livestock, however, the adaptations identified are also applicable to the livestock processing industry.

This future scenario outlines possible climate impacts, risks, adaptation measures and ongoing management measures at a hypothetical site in NSW.

Scenario

A large corporate-scale livestock piggery farm in the Illawarra-Shoalhaven region of New South Wales (NSW) has recently experienced periods of heavy rainfall. During this period, the otherwise carefully managed effluent systems and feed storage infrastructure were compromised raising concerns with excess runoff and contamination of nearby land and waterways.

Farm management undertook preliminary investigations to better understand the farm’s exposure to climate risks such as extreme rainfall, amongst others. The investigations indicated that while average annual rainfall in the region may decline over the century, the intensity of individual rainfall events is expected to rise by approximately 7% for every degree of warming¹. This increases the risk of flash flooding and system failures. By 2050, the region is likely to experience a 45mm increase in rainfall depths during a 1 in 100-year, 24-hour storm duration under a higher emission scenario (compared to a Bureau of Meteorology baseline)².

Climate impacts

During the recent period of extreme rainfall, the farm experienced several climate impacts that led to the overflow of untreated effluent and a breach of environmental license conditions. These impacts included:

• effluent ponds being overwhelmed by high volumes of rainfall, resulting in the uncontrolled discharge of nutrient-rich waste into surrounding land and waterways.
• stormwater inflow into animal housing and feedlots, increasing the risk of manure runoff and nutrient leaching into soils and nearby water bodies.
• wastewater treatment systems at the farm became overloaded, reducing treatment efficiency and leading to discharges that did not meet license requirements.
• flood related power outages at animal housing, causing system shutdowns and emergency releases of untreated waste.

Following the extreme rainfall event, farm management identified that while these specific components were affected during this event, other parts of the system may also be vulnerable to future climate extremes. These events not only threaten the farm’s operational continuity but also contribute to environmental degradation, including nutrient loading in rivers and land surfaces, algal blooms, and declining water and land quality.

It was also noted that much of the farm’s water management infrastructure was designed based on historical climate data and therefore may not be equipped to handle the increasing frequency and intensity of extreme weather events. Without the adaptive capacity to manage increasing rainfall, such environmental pollution incidents are likely to become more commonplace.

Assessing climate risk

To understand the climate change risks on the farm, and to prioritise climate risk management, farm management undertook a system wide climate change risk assessment using climate change projection data for rainfall, temperature, bushfire, storms and other relevant climate variables. While several climate hazards and potential climate related impacts related to the facility were identified, this scenario focusses on increased volume and intensity of rainfall, resulting in waterway and land pollution impacts.

The assessment was undertaken across the multiple future timeframes using projected climate data for a medium and high emissions climate scenario. The farm was found to be at higher risk of polluting waterways and land during extreme rainfall events.

Identifying adaptation measures

With the key climate risks identified, key stakeholders such as asset managers and operators collaborated to identify potential adaptation measures that could be implemented to reduce these climate risks. The adaptation measures targeted different infrastructure components and vulnerabilities of the farm, with each having different levels of feasibility and effectiveness in addressing climate change induced environmental impacts. These included:

• For the farm’s existing operations – farm management should assess the farm’s existing effluent ponds, leachate ponds, and drainage systems against relevant standards and guidelines, such as the Australian Rainfall and Runoff Guidelines (ARR) 2019 v4.2 (or latest revision available), to understand the capacity and ability of the system to abide by compliance requirements under projected climate conditions. The ARR guidelines provide climate change factors for various climate scenarios, rainfall intensities, and durations and should be determined by a suitably qualified professional. The outcome of this assessment will inform if and where upgrade works may be required.
• For any new or upgraded farm operations – best practice farm management should embed climate resilience from the outset. This includes designing effluent containment, stormwater diversion, and housing systems in accordance with the latest guidance, such as ARR 2019 v4.2 guidelines (or latest revision available), to ensure they can withstand future climate extremes and continue to meet environmental compliance requirements.
• Collaborating on enhancing water catchment management – Farm management could consider working with local councils, water authorities, and neighbouring landholders to reduce stormwater inflows and manage runoff. This may involve sealing effluent pond liners, improving stormwater diversion around feedlots, and addressing shared drainage issues that contribute to system overload during heavy rainfall.
• Prioritising preventive maintenance – Farm management should implement regular inspection and maintenance regimes of effluent systems, pumps, and drainage infrastructure to ensure optimal performance. Preventative actions such as clearing blockages, repairing leaks, and maintaining filter systems can reduce the risk of overflows and environmental breaches during extreme weather events.
• Embedding system redundancy – To maintain operations during extreme climate events, farm management could incorporate redundancy measures such as backup power supplies for pumps and aerators, or alternative effluent flow paths. These measures help prevent system failures and uncontrolled discharges when primary systems are compromised.
• Updating operational plans and procedures – Farm management should review and revise key documents such as flood risk management plans, seasonal preparedness protocols, and effluent management manuals. Adding a climate lens to these plans ensures that roles, responsibilities, and response actions are clearly defined and aligned with future climate scenarios.

Ongoing management of climate impacts

The above adaptation measures focus on addressing an increased volume and intensity of rainfall resulting in potential pollution to surrounding land and waterways. This represents a sample of the long list of potential actions farm management identified which will be included in a climate adaptation plan for the farm.

An adaptation pathway was then developed to ensure that adaptation measures are prioritised and implemented based on key trigger points. Key trigger points were identified based on when the climate change impacts may eventuate in environmental risk, as well as taking into consideration the age, conditions and criticality of the infrastructure and likely timelines for infrastructure upgrades. The adaptation pathway they have developed enables them to address the high-risk, time critical climate change impacts now while remaining open to future adjustments as the climate evolves.

Climate risk management is an iterative process and should be reviewed periodically to ensure the risk assessment and adaptation pathway remain effective and appropriate into the future. By planning ahead and embedding adaptability into both farm management practices and infrastructure, the farm can reduce its vulnerability, safeguard its operations, and protect and/or improve existing environmental conditions.