TITLE:
Characterisation of Hydrological Drought and Implications for Sustainable Water Resources Management in the Sokoto-Rima River Basin (SRRB), Nigeria
AUTHORS:
Martins Yusuf Otache, Onemayin David Jimoh, John Jiya Musa, Abdullahi Danmagaji
KEYWORDS:
Hydrological Drought, Water Resources, Sustainability, Management, Climate Change
JOURNAL NAME:
Open Journal of Modern Hydrology,
Vol.10 No.3,
June
19,
2020
ABSTRACT: Hydrological drought is
usually characterised by water loss over time from both underground and surface
supplies. Thus for this study, the assessment of hydrological drought was
carried out by employing Cumulative Rainfall/Streamflow Anomaly as preliminary tools for the presence of drought signatures while
detailed characterisation was via Streamflow Drought Index (SDI). The results
revealed that hydrological drought was observed in all the stations; however,
though in general, the stations could be classified as experiencing near normal
drought conditions with mild drought signatures. The findings also revealed
that the average streamflow deficit volume and durations of the hydrological
drought severity were 1.780 Mm3 and 192 months, 1.444 Mm3 and 252 months, 3.148 Mm3 and 252 months, and 0.159 Mm3 and 372 months for Bakolori, Goronyo (pre dam construction era), Goronyo (post
dam construction era) and Zobe stations, respectively. The results also
revealed the relevance of flow duration curve and analysis of frequency of
drought state transition for the development of scenario-based basin water
resources management protocol. The coefficient of determination (R2)
statistic of the developed regression models indicate that 73.3% and 86.5%
variation in streamflow dynamics across the Basin can be explained by climate
change variables. However, for sustainable management of water resources in the
Basin, it is imperative that characterisation of hydrological drought and
monitoring should employ robust indices which use improved monthly
precipitation estimates under global warming scenario in addition to ensuring
that there is a shift from reactive to proactive approach in order to combat
hydrological risk. Hence, a robust framework that finds application both for
planning mitigation actions which embody strategic, tactical and emergency
components should be designed; to this end, analysis of persistence and
recurrence of drought in time and determination of possible recurrent patterns
are necessary.