The final rehabilitated landform of the Ranger Uranium Mine in Australia is required to safely encapsulate mine tailings for a period of at least 10,000 years. A practical means of assessing the ability of a landform to contain tailings over an extended time period is through the use of landform evolution models (LEMs). However, such models require datasets that are able to represent the long-term climatic variability of the region. The Alligator Rivers Region, in which the mine is located, experiences seasonal, high-intensity rainfall events. However, comparatively little rainfall data exists for the region that is suitable for long term modeling. Therefore, a specific concern is that any simulation that utilises the historic rainfall data would only represent rainfall variability over a relatively short period and not account for the range that might be expected over a period of up to 10,000 years. To address this, we applied a spatial analogue approach to develop point scale hourly rainfall scenarios that incorporate the range of projected increase/decrease in rainfall for the Ranger site in line with climate change predictions. These were used as inputs to the CAESAR-Lisflood LEM to simulate the evolution of a conceptual rehabilitated landform for a period of 1,000 years. Using this approach, we were able to identify the extent, distribution and pattern of erosion and gully formation under rainfall scenarios arising from different climate projections. The results of these simulations indicate areas of improvement in landform design and provide increased confidence that the use of analogue rainfall scenarios in the CAESAR-Lisflood LEM will be able to correctly predict the long-term evolution of a rehabilitated landform. Furthermore, the approach used in this study can be easily transferred to other sites where rainfall variability is significant and climate change impacts are uncertain.
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