The Shepparton Irrigation Region (SIR) is a highly productive, intensively irrigated region, producing much of Victoria’s, and indeed Australia’s, agricultural production. Approximately 317,000 of its 500,000 hectares can be irrigated for dairy, cropping, stone and pome fruit production. The SIR uses around 1.2 million megalitres of water a year and creates agriculture products worth an estimated 1.38 billion dollars in 2006 and, in turn, supports a large food processing industry. The region is heavily dependent on agriculture and food manufacturing for employment.
A land and water management plan for the SIR was prepared in 1989. This was supported by a number of sub-strategies. All documents have been regularly reviewed and updated.
The SIR has been subjected to a number of significant pressures/ divers including:
- a significantly drier climate
- a major drought
- reduced consumptive water availability
- declining water tables
- increased opportunities for water trade
- irrigation system modernisation and reduced footprint of irrigation
- changing farm enterprises
In addition, the outlook for the future climate of the SIR is for significant change including:
- higher temperatures in all seasons
- more hot days and fewer very cold days
- decline in winter rainfall
- increase in summer rainfall
- increased extreme rainfall intensity
- natural rainfall variability may mask trends to average rainfall particularly in summer
- evapotranspiration may rise particularly in summer and autumn
It has become apparent that the paradigm driving the development and implementation of the SIR’s plans has changed significantly. The process of updating plans, currently under way, uses a combined resilience and adaptation pathways approach that involves:
- Identifying and describing key attributes of the region. These describe the identity or state of the SIR, at a high level. They are attributes of the region that if changed beyond a certain point (threshold) would result in a fundamental change in the state of the region. There is a deliberate effort to try and identify only 5 or 6 big ticket items. The attributes identified are watertables, extent of native vegetation, water availability and farm processor viability. Indicators are attached to each key attribute.
- Identifying thresholds for each attribute. The threshold is the point at which the key attribute changes and affects the fundamental state of the region. For example clearing of more than 97% of the native vegetation if the region would represent a fundamental change to the nature of the region. Further work is required to identify or refine thresholds for other key attributes.
- Describing 4-5 future state scenarios that include consideration of the likely impacts of climate change. Simplistically, a number of regional future state scenarios (and a base or current state) can be described in the four quadrats outlined in figure 35 by two axes representing potential climate futures (drier and hotter through to wetter and hotter) and a range of potential land uses (peri urban through to intensive agriculture). The key here is to have just enough information to facilitate the process.
- Assessing the risk to key attributes in the future state scenarios. This step identifies the likelihood of thresholds being crossed for each key attribute in each of the identified scenarios. For example, in a hotter and drier future state an increase in the area with watertables at less than 2 metres in depth is unlikely but in a wetter future state it is highly likely. This provides valuable information about the direction of required management in the future.
- Assessing current and potential future management actions that are, or could be, used to mitigate risks. Risks can be mitigated by implementing management actions. For example, the likelihood of the area of the region with watertables at less than 2 m in depth can be mitigated (managed) by encouraging farmers to pump groundwater. The confidence that the management action will achieve the desired outcome can also be assessed.
- Implement management and monitoring. An outcome of this process is that management plans are developed (or updated) and implemented. Monitoring thresholds and actions will gather data that will inform management review and improvement.
- Reviewing and improving. An annual planning cycle embedded within a longer, five year adaptive planning cycle requires monitoring of thresholds and management actions that will oblige managers to evaluate the state of key attributes and if necessary, revise and improve plans. Management actions will be focused on things that matter.
The process can be applied at a range of levels of detail. For example, a management board might focus at a strategic level on the key attributes listed above. A program or project manager will require much more detail including an expanded set of indicators (for example extent of native vegetation could be expanded to consider quality as well as quantity). The expanded set can be collapsed for upwards reporting.
Figure 35: Potential Shepparton Irrigation Region Futures