Surfacewater and groundwater interaction
The Department of Water sustainably manages the state's water resources. In many places surfacewater and groundwater interact requiring their management to be integrated. Understanding the water quality of the interacting resources complicates the hydrology and is an important consideration for management.
Examples of the types of hydrology in WA where understanding surfacewater/groundwater interaction is essential are listed below. In these areas, all parameters need to be understood to quantify and manage the water resource:
- Losing/gaining reaches on rivers like Capel River, Blackwood River and Gingin Brook where groundwater discharges into the surfacewater or surfacewater recharges groundwater.
- Swan Coastal Plain (SCP) wetlands like Loch McNess, Thompson Lake and Spectacles Lake where the groundwater levels interact with the lake levels.
- Areas undergoing urbanisation on the SCP south of the Swan River where groundwater levels are near the surface and the urbanisation process will reduce evaporation and increase the available water. This requires the management of groundwater levels and surfacewater flows.
- Alluvial aquifers which are recharged by flood events (eg. Gascoyne River at Carnarvon, Lower Yule River in Pilbara).
- Changes in land use, changes in management and changes in climate change may impact on surface water and groundwater (including the water quality of each). These cannot be considered in isolation.
Case Study: A major project that required detailed assessment of surfacewater/groundwater interaction was the Murray drainage and water management plan. This work used the extensive information in the study area to model water behaviour under current and future conditions.