Gold mining has been a major economic activity in the central Bendigo region over the last century and a half. Due to the shallow water-tables in the area, these (underground) mining activities have required removal of groundwater (i.e. ‘mine dewatering’), which has lowered the water table in the area below its natural levels.
In 2012, mining of the modern workings and associated dewatering ceased. Since this time the water table in the central Bendigo area has started to recover. This groundwater in the mine workings has elevated levels of salt, arsenic, other heavy metals and hydrogen sulphide (rotten egg) gas which, in turn, is expected to have a range of different impacts on the Bendigo and broader Victorian community.
The Department of Environment, Land, Water, and Planning (DELWP) engaged Natural Capital Economics to help develop a sound and shared understanding of these potential impacts in economic terms. The study built on and further developed previous economic studies that have been undertaken on the issue. A key focus of this study was to underpin the economic analysis with best-available scientific information.
The study assessed four main impact categories in quantitative terms:
- Damage to waterway ecosystem health and loss of related ecosystem services
- Degradation of consumptive water resources used in the Bendigo Creek and the Torrumbarry Irrigation District
- Damage to the Central Deborah Gold Mine assets and loss of related tourism activity; and
- Loss of urban amenity associated with hydrogen sulphide emissions (‘rotten egg smell’)
The project findings have helped establish the evidence-base needed to inform how the Bendigo groundwater problem can be best managed over the medium and long term.