TITLE:
Regional Drought Severity Assessment at a Basin Scale in the Limpopo Drainage System
AUTHORS:
Berhanu F. Alemaw, J. M. Kileshye-Onema, D. Love
KEYWORDS:
Drought; Standardized Precipitation Index; Drought Severity; Drought Severity-Area-Frequency (SAF) Curves; Limpopo Basin
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.5 No.11,
November
29,
2013
ABSTRACT: A spatial analysis of drought characteristics in the
Limpopo basin is undertaken to evaluate its regional implications to water
management challenges. In this study, drought duration, frequency and severity
are investigated. In addition drought Severity-Area-Frequency (SAF) curves were
constructed. The entire Limpopo River Basin is subdivided into four homogeneous
regions based on topographic and climate variations in the basin, which
was constructed with the K-Means Clustering algorithm. Using the medium range
time series of the Standardized Precipitation Index (SPI) as an indicator of
drought for each homogeneous region, monthly and annual SAF curves and maps of
probability of drought occurrence were produced. The results indicated
localized severe droughts in higher frequencies compared to moderate to severe
low frequency droughts spread over wider areas in the basin. The approach can
be used to develop improved drought indicators to assess the relationship
between drought hazard and vulnerability and to enhance the performance of
methods currently used for drought forecasting. In general, this preliminary
investigation reveals that the western part of the basin will face a higher
risk of drought when compared to other regions of the Limpopo Basin in terms of
the medium-term drought patterns. The Limpopo Basin is water stressed and
livelihood challenges remain high, thus impacts of droughts and related
resilience options should be taken into account in the formulation of regional
sustainable water resources development strategies.