The water resources of the South East (SE) region are important for South Australia as a whole. They support primary industries including wine, wool, meat, dairy, forestry and timber, fishing and aquaculture, vegetables and seed production. Given the absence of reliable surface water in the region, groundwater is the dominant source of water for agriculture and industry. Furthermore, groundwater is the primary water source for town supply, stock and domestic use in the SE.
There are two main water resource management questions in the SE. The first, mainly focused in the Lower SE, is the sustainable long term management of the groundwater resources, used for agriculture, industry, town water supply, stock and domestic use as well as supporting a significant proportion of the ecosystems and streamflow in the region. How to balance these consumptive uses, along with ensuring enough water remains to sustain the environment, is a difficult and ongoing question. The second water resource management question in the SE is mainly focused in the Upper SE, where there is an extensive drainage network that can be used to divert water across the landscape. The volume of water available of suitable quality is generally not sufficient to support all of the (mostly) environmental demands for this water, and as such decisions must be made as to which assets will have water diverted toward them each year.
The objective of Milestone 1 of Task 1 of this project was to scope the structure of a decision support framework, relevant to assist decision making in the SE - for both operational and policy decisions, with the flexibility to incorporate new data/ models as they become available, and the uncertainty inherent in such information. The research proposed as Milestone 2 of Task 1 was moved to a follow on project, E.2.4.
The objective of Task 2 was to improve the understanding of the relationship between groundwater and drains in the South East, and how this varies in time and space. In most areas, drains collect groundwater, but in other areas water flowing in drains leaks into the groundwater system. Although water and salt flows in the drains support numerous important wetland ecosystems, there is insufficient knowledge on the magnitudes of these flows, the associated salt fluxes, and how they vary across the region.
Work taken place during Task 1 largely consisted of a literature review to form one basis for further work in the South East region, as such the main body of work undertaken provides a review of current science, as opposed to developing new science. This was a critical step to ensure the follow on project (E.2.2), as well as all projects in the environmental water stream, addressed the knowledge limitations for water management in the South East. This will allowed research outcomes to be achieved while still providing valuable input to operational and policy decision in the South East.
Task 2 of this project was considered to be a foundation for further work on surface water – groundwater interactions around the drains in the South East. The range of radon activities observed and the preliminary results in general, coupled with the highly geometric and controlled nature of the drains, suggested that this system had the potential to be a future centrepoint of research into surface water – groundwater interactions.