Drought severity–duration–frequency curves: a foundation for risk assessment and planning tool for ecosystem establishment in post-mining landscapes

Abstract

Abstract. Eastern Australia has considerable mineral and energy resources, with areas of high biodiversity value co-occurring over a broad range of agro-climatic environments. Lack of water is the primary abiotic stressor for (agro)ecosystems in many parts of eastern Australia. In the context of mined land rehabilitation quantifying the severityduration-frequency (SDF) of droughts is crucial for successful ecosystem rehabilitation to overcome challenges of early vegetation establishment and long-term ecosystem resilience.The objective of this study was to quantify the SDF of short-term and long-term drought events of 11 selected locations across a broad range of agro-climatic environments in eastern Australia by using three drought indices at different timescales: the Standardized Precipitation Index (SPI), the Reconnaissance Drought Index (RDI), and the Standardized Precipitation-Evapotranspiration Index (SPEI). Based on the indices we derived bivariate distribution functions of drought severity and duration, and estimated the recurrence intervals of drought events at different timescales. The correlation between the simple SPI and the more complex SPEI or RDI was stronger for the tropical and temperate locations than for the arid locations, indicating that SPEI or RDI can be replaced by SPI if evaporation plays a minor role for plant available water (tropics). Both short-term and long-term droughts were most severe and prolonged, and recurred most frequently in arid regions, but were relatively rare in tropical and temperate regions.Our approach is similar to intensity-duration-frequency (IDF) analyses of rainfall, which are crucial for the design of hydraulic infrastructure. In this regard, we propose to apply SDF analyses of droughts to design ecosystem components in post-mining landscapes. Together with design rainfalls, design droughts should be used to assess rehabilitation strategies and ecological management using drought recurrence intervals, thereby minimising the risk of failure of initial ecosystem establishment due to ignorance of fundamental abiotic and site-specific environmental barriers, such as flood and drought events.

Drought hotspot analysis and risk assessment using probabilistic drought monitoring and severity–duration–frequency analysis

“…The modelling of return period of drought events is vital for water resources management and drought adaptation. Previous studies by Shiau and Modarres (), Shiau (), Serinaldi et al (), and Halwatura et al () provide useful information on estimation of bivariate return periods for drought frequency analysis. In Equation , the expression for conditional return period T S ∣ D ( d ) is presented.…”

Characteristics of Droughts in South Africa: A Case Study of Free State and North West Provinces

“…As reported in Halwatura et al [12], drought periods can be characterized from a few hours (short-term) to millennia (long-term). The time lag between the beginning of a period of water scarcity and its impact on socio-economic and/or environmental assets is referred to as the timescale of a drought [13].…”

Temporal-Spatial Characteristics of Drought in Guizhou Province, China, Based on Multiple Drought Indices and Historical Disaster Records

“…e derived drought variables [54,55] based on the Run eory follow the de nitions ( Figure 2). Drought duration is de ned as the number of months from the rst month in which the indicator goes lower than −1 to the last month with a negative value before the indicator returns to positive values.…”