The Mount Lofty Ranges (MLR) provides water for the environment, recreational activities, stock, intensive horticulture, secondary industries, as well as public potable water supplies. The MLR supports diverse ecosystems within agricultural and rapidly expanding peri-urban landscapes. Native fish, invertebrates and plants are key components which maintain water quality, nutrient retention and recycling, sediment dynamics, and food resources, which all contribute to a healthy, functioning ecosystem.
The water resources of the MLR were prescribed in 2005. Water allocation plans set out the rules for managing the allocation ofthis water to a range of stakeholders. The plans ensure these resources are allocated fairly and secure sustainable water supplies for the community, industry and the environment for future generations.
A Goyder Institute for Water Research project was established to provide additional information and tools to support water allocation planning in the MLR. The work has brought together new methodology and ideas from multiple research agencies. The first step was to establish seven additional monitoring sites to complement other monitoring programs where there were known gaps in knowledge of the flow regime and the health of the MLR ecosystems. In particular, monitoring sites were chosen to improve our understanding of hydro-ecological processes under low flow situations.
The new data collected at these instrumented sites (stream flow, vegetation, macro-invertebrates and fish) was combined with previous data collected from other parts of the MLR to provide a comprehensive database on stream flow and ecosystem health across the MLR. The database also included the quality of stream water as well as quantity. Several modelling and new statistical approaches were then used to develop relationships between stream flow and quality and the health of the vegetation, macroinvertebrates and fish (i.e. response models). This study covered a broad range of habitats and the fish community was sufficiently diverse to detect changes within the entire region.
This project has demonstrated the importance of accurate collection and use of empirical data to model responses to proposed water use scenarios and the ability to quantify the ‘maintain and improve’ components of water allocation planning objectives.
The project was successful in building the statistical and modelling capability of the research organisations involved; needed to fully understand the relationships between water flow and quality and the response of the ecosystem to this water resource.