Analysis of Water Quantity and Quality Trade-Offs to Inform Selective Harvesting of Inflows in Complex Water Resource Systems

Challenges faced by water resource systems are multi-faceted. The problem can be even more pronounced in a dry continent like Australia where the water resources can often be afflicted by high salinity and turbidity. Therefore, modern water resource systems require to appropriately manage both water quality and quantity. This study aims to illustrate the trade-offs between water quantity and quality in a reservoir, based on decisions to harvest different inflow sources. Taylors Lake of the Grampians reservoir system in Western Victoria, Australia was chosen as the case study for this research as it is sufficiently complex and includes many of the contemporary water resources challenges seen around the world. Different operational scenarios were analysed which included increasingly stringent water quality criteria before the water was harvested or otherwise allowed to by-pass the storage. The study suggests that selective harvesting of water can be an option to improve the overall and long-term water quality within a reservoir, but stringent water quality measures can lead to an associated loss of overall water quantity. This research study provides useful insight to water planners and stakeholders in similar catchment settings around the world, to identify water harvesting regimes with competing water quality constraints.

Automated summary

This study focuses on the trade-offs between water quantity and quality in a reservoir, using Taylors Lake of the Grampians reservoir system in Australia as a case study. Selective harvesting of water can improve overall water quality in a reservoir, but stringent water quality measures may lead to a loss of overall water quantity.