Assessing the frequency of drought/flood severity in the Luvuvhu River catchment, Limpopo Province, South Africa

Abstract

The Luvuvhu River catchment experiences rainfall variability with a high frequency of extremely dry and wet conditions. Understanding the frequency of drought and floods in this catchment area is important to the agriculture sector for managing the negative impacts of these natural hazards. This study was undertaken to investigate the frequency and severity of drought/floods and linkages with the El Niño Southern Oscillation (ENSO) phenomenon. Poor and resource-limited small-scale farmers in the Luvuvhu River catchment area struggle to adjust due to decreasing crop yields and livestock mortality caused by drought and floods. Monthly rainfall data from 15 grid points (0.5° × 0.5°) was used to compute the Standardised Precipitation Index (SPI) for the period between 1979 and 2016. The 3-month SPI was calculated for the December–January–February (DJF) period. The second half of the agricultural season was selected because the influence of ENSO is high during the late summer season (DJF) in the catchment. The SPI results indicate that the agricultural seasons 1982/83, 1991/92 and 2015/16 were characterised by extreme drought. Conversely, the SPI values also show that the wettest seasons were recorded in 1998/99 and 1999/00. The catchment experiences a high frequency of moderate to severe drought in the north and north-eastern parts. Spatially, the occurrence of moderate to severe dry conditions covers large areas in the north and south-western parts. Severe to extreme wet conditions cover large areas in the north and south-eastern parts of the catchment. The SST index (Niño 3.4) shows a strong influence on rainfall variability in the catchment, resulting in either dry or wet conditions. Therefore, this study recommends further research focusing on more climatic modes that influence rainfall variability, as well as further development of drought and flood forecasting to improve farmers’ adaptations options and reliability of weather forecasts used as a tool to manage crop production.

Applying a WASH Risk Assessment Tool in a Rural South African Setting to Identify Risks and Opportunities for Climate Resilient Communities

“…Linkages between the frequency and intensity of droughts and flooding have been seen in the El Nino Southern Oscillation (ENSO) phenomenon [ 21 ]. The flood disaster that occurred in December 2010–January 2011 was linked to a La Nina event and caused massive displacement of people and numerous deaths.…”

El Niño-Induced Drought Impacts on Reservoir Water Resources in South Africa

“…Since rainfall is a major contributor to reservoir water resources, a reduction in annual precipitation negatively impacts water supply to different water users. Studies focused on drought such as [18][19][20][21][22] have been conducted in the LRC. However, these aimed to characterise, assess, and predict drought events and not much attention has been directed to evaluate the relationship between El Niño-induced drought and reservoir water resources.…”

Spatiotemporal Characteristics of Drought and Wet Events and Their Impacts on Agriculture in the Yellow River Basin

“…Ekwezuo et al [5] analyzed the regional characteristics of meteorological drought and flood in West Africa and found that the severity of drought in the region showed a decreasing trend, while the severity of floods increased; however, droughts and floods have always been the biggest threats to food production and security in West Africa. Scholars have evaluated the frequency of drought/flood severity in the Luvuvhu River basin, Limpopo Province, South Africa, and found that the frequency of moderate to severe drought increased from south to north, with most of the basin affected by severe drought, sloping to the northeast of the basin, and the northwestern parts of the basin experienced a high frequency of severely wet to extremely wet conditions [6]. Research has shown that meteorological drought in the Yellow River basin (YRB) has been increasing, and its distribution is expanding [7][8][9], while drought has shown a decreasing trend on both seasonal and annual scales [10].…”