| Title: | Characterization of droughts in humid subtropical region, Upper Kafue River Basin (Southern Africa) |
| Authors: | Lweendo, M.K., B. Lu, M. Wang, H. Zhang and W. Xu |
| Year: | 2017 |
| Journal: | Water |
| Volume (Issue): | 9(4) |
| Pages: | |
| Article ID: | 242 |
| DOI: | 10.3390/w9040242 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | drought assessment |
| Secondary Application Category: | groundwater and/or soil water impacts/processes |
| Watershed Description: | 104,514 km^2 Upper Kafue River which drains to Itezhi-tezhi Dam in northwest Zambia |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | In this study, an integrated approach involving multiple standardized indicators and
hydrological modeling (Soil and Water Assessment Tool, SWAT) was evaluated to reconstruct and
characterize meteorological, agricultural and hydrological droughts in Upper Kafue River Basin of
Zambia during 1984–2013. Standardized Precipitation Index (SPI) and Standardized Precipitation
Evapotranspiration Index (SPEI) were used to identify meteorological droughts. Standardized Soil
Moisture Index (SSI) was applied to characterize agricultural droughts and Standardized Runoff
Index (SRI) was calculated to illustrate hydrological droughts. Input data for SRI and SSI computation
was obtained from SWAT model which simulated daily and monthly runoff well with Nash–Sutcliffe
efficiency (NSE) and coefficient of determination (R
2
) greater than 0.65. The results showed that:
(1) all indices were able to detect temporal variability of major drought events in a humid subtropical
basin in Southern Africa; (2) SWAT successfully simulated runoff and soil moisture although soil
moisture requires further calibration to increase accuracy; (3) the average duration and intensity for
meteorological droughts at three-month time scale were lower but frequencies were higher compared
to agricultural and hydrological droughts at 3- and 12-month aggregates; and (4) drought events
exhibited a negative trend as evaluated by Mann–Kendall on SPEI, indicating an increase in drought
severity, and correlation analysis between SPEI and SRI revealed that SPEI at 9–15 months has a strong
link with hydrological conditions. This study showed that a comprehensive assessment of droughts
by integrating multiple variables provided a versatile tool for drought monitoring and mitigation. |
| Language: | English |
| Keywords: | : drought indices and characterization; hydrological modeling; Soil and Water Assessment
Tool; humid subtropical region |