In early January 2016 a major bushfire swept down from the parched Darling Escarpment and across the farms of Western Australia’s Swan Coastal Plain. At its worst the Waroona fire, could be seen from space and with the naked eye from Perth, 118 km north. The fire was so large that it formed its own weather system, a massive pyro-cumulonimbus cloud form, which generated unpredictable winds, lightning, and ember showers.
Over seventeen days the fire burned a total area of 69,165 ha comprising 31,180 ha of private property and 37,985 ha of public land. One hundred and eighty one properties were destroyed. The small town of Yarloop, home to around 500 people, was virtually wiped out. Tragically, two residents also lost their lives.
It has been estimated that the cost of the fire, including the costs of suppression, losses, damage and recovery totalled approximately $155 million. The comparative impact of the fire on the regions hydrometric monitoring network was, relatively, negligible, (costed at a $40,000 for the Corporation, $30,000 for Harvey Water and $10,000 for the Department of Water and Environmental Regulation (DWER)) however the impact on the surrounding environs was significant.
Within the Samson Dam catchment, the fire was extremely intense and wide spread. This resulted in extensive loss of vegetation and natural buffers within the catchment and surrounding properties. This included 100% of the riparian zones. This not only presented a high risk for erosion, and adverse water quality in supply reservoirs and the sensitive Peel Harvey Estuary, but also threatened the stability of local ecological communities.
However out of the ashes rose a range of exciting opportunities for water resource management in WA. In fire prone areas of the southwestern Australia knowledge on the impacts of wildfire on water quality is relatively minor. In the case of wildfire where water and aquatic assets are involved community, industry and resource managers have few means to prioritise their mitigation efforts.
In the wake of the 2016 Waroona fire a university study utilised available discharge and water quality data to examine the role of wildfire in causing erosion and producing water quality impacts.