Bernard Moeketsi Hlalele
Abstract
A dry spell is defined as the consecutive number of days with precipitation less than a specified threshold value of a standardised precipitation index (SPI). A cumulative effect of these dry spells amount to drought events and thereby negatively affect socio-economic activities in the communities. The ...
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A dry spell is defined as the consecutive number of days with precipitation less than a specified threshold value of a standardised precipitation index (SPI). A cumulative effect of these dry spells amount to drought events and thereby negatively affect socio-economic activities in the communities. The current study aimed at determining the influence of El Niño-Southern Oscillation (ENSO) aided by Southern Oscillation Index (SOI) in order to make easy prediction given clear SOI cyclicity of anything from 3 to 7 years. The study used SPI to define dry spells and was also used a conceptual framework to quantify dry spells. A spectral analysis was also applied to SPI-1 time series datasets to determine return levels to provide government and all relevant authorities with behavioural characteristics of dry spells in the area for proactive mitigation strategies. Main results of this study ENSO having no direct influence over all the selected station’s precipitation. All the stations showed an average of 12 months or 1 year return level. This implies that after every 1 year, the study area is highly likely to experience dry spells which could lead to detrimental effects of the most important amenities of the study area. This phenomenon provides authorities with relevant information to plan proactively as dry spells may amount or graduate to drought events and thereby adversely affect water consuming activities in the area.
Bernard Moeketsi Hlalele
Abstract
Drought is a major environmental problem that affects agriculture, water resources, and communities around the world. In the Lesotho Highlands commercial dams, drought can have a significant impact on agricultural production, water supply, and local livelihoods. Understanding the patterns and severity ...
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Drought is a major environmental problem that affects agriculture, water resources, and communities around the world. In the Lesotho Highlands commercial dams, drought can have a significant impact on agricultural production, water supply, and local livelihoods. Understanding the patterns and severity of drought is crucial for effective water management and agricultural planning. This study aimed to analyse and understand the patterns of agricultural drought in the Lesotho Highlands commercial dams through the use of the Standardized Precipitation Index (SPI) and the theory of runs, as well as various drought parameters. The study used Average Dry Spell Duration, Drought Tendency, Longest Dry Spell Duration, Longest Multi-year Drought, Largest Single Year Drought, Standard Total Accumulative Dry Spell, and Number of Consecutive SPI-values, to provide a comprehensive analysis of the drought situation. The results revealed that the precipitation levels at the four dams were relatively similar, but with a potential increase in precipitation at Muela Dam. The SPI-3 and SPI-6 analyses showed a significant downward trend indicating an increase in dryness in the area. The drought parameters did not show significant differences between the stations/dams, indicating similar levels of drought across the dams. The study recommends regular monitoring of precipitation and drought conditions using the SPI and other water-balance drought indices, development of water conservation and management strategies, use of drought-resistant crops and water-efficient agriculture practices, and increased collaboration among stakeholders for sustainable water management and agricultural resilience.
