Frequency and severity of drought in the Lake Victoria region (Kenya) and its effects on food security

Awange, Joseph; Aluoch, June Akinyi; Ogallo, Laban; Omulo, Monica A.; Omondi, Philip

doi:10.3354/cr033135

Cited by 55 publications

(35 citation statements)

References 8 publications

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“…There are a Kayombo and Jorgensen, 2006) number of other meteorological stations within the LVB, but all are found in the same (Lake Victoria) climatological zone with homogeneous anomalies. Past studies have shown significant homogeneity in the patterns of rainfall anomalies in East Africa including Lake Victoria basin, resulting into common use of single rain gauge location to represent large areas (Ogallo 1988(Ogallo , 1993Basalirwa et al 1993;Awange et al 2007b). Several authors have also noted that large scale moisture transported by monsoonal winds enhance basin precipitation significantly.…”

Section: Data Sourcementioning

confidence: 95%

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Falling Lake Victoria water levels: Is climate a contributing factor?

et al. 2008

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Recently, and perhaps most threatening, Lake Victoria water level has been receding at an alarming rate. A recent study suggested the possibility of the expanded hydroelectric power station in Uganda. However, since the lake receives 80% of its refill through direct rainfall and only 20% from the basin discharge, climatic contributions cannot be ignored, since the 80% water is directly dependant on it. It is therefore necessary to investigate climatic contribution to the declining Lake Victoria water level observed over a long period, i.e., 30 years. This contribution uses 30 years period anomalies for rainfall, river discharge and lake level changes of stations within Lake Victoria basin to analyse linear and cyclic trends of climate indicators in relation to Lake levels. Linear trend analysis using the Student's t test indicate a decreasing pattern in rainfall anomalies, with the slope being statistically similar to those of water levels at both Kisumu, Maziba and Jinja stations Climatic Change (for the same period of time , thus showing a strong correlation. On the other hand, cyclic trend analysis using Discrete Fourier Transform (DFT) shows cyclic period of water level to coincide with those of droughts and rainfall. The strong relationship between climatic indicators of drought and rainfall on one-hand and lake levels on the other hand signifies the need to incorporate climate information in predicting, monitoring and managing lake level changes.

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Section: Data Sourcementioning

confidence: 95%

“…The 30-years' mean was in accordance with World Meteorological Organization (WMO) requirement that this be the standard used to define the rainfall 'normal' of a region (Awange et al 2007b). Using Eqs.…”

Section: Analysis Approachmentioning

confidence: 99%

Falling Lake Victoria water levels: Is climate a contributing factor?

et al. 2008

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“…Personal communication to local people explains that in the past, the Simiyu River maintained notable annual water flow however, the current situation observed during this study, showed reduced and stagnant water pools during dry months of the year (June -August) and significant water discharge only during the rainy season (March -May). This is explained to be associated with agricultural activities being undertaken along the river basin and reduced rainfall in the region due to climatic changes in the region (Swenson and Wahr, 2009;Awange et al, 2007;2008). Sampling of surface Lake water was done during periods of high runoff (MarchApril) and periods of low runoff (JuneAugust) in 2007 -2009.…”

Section: Materials and Methods Study Area And Samplingmentioning

confidence: 99%

Significance of terrestrial inflows to carbon and nitrogen distribution in the Lake Victoria surface water

Tungaraza¹,

Mato²,

Mkoma³

et al. 2011

International Journal of Biological and Chemical Sciences

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This was an investigation to characterize seasonal and spatial distribution of particulate organic matter (POM) in the surface water of Lake Victoria at Speke Gulf, by using carbon-13 and nitrogen-15 isotopic signatures. Speke Gulf is under the influence of terrestrial inflow through river Simiyu. The POM from the lake surface water had higher C:N ratio values decreasing towards the deeper lake water, an indication of decreasing nitrogen content relative to carbonic materials. Samples away from the river mouth provided C:N ratios within the Redfield ratio range (C:N:P; 106:16:1) indicating materials of phytoplanktonic origin. The POM isotopes composition indicated a maximum δ 13 C value of −21.2‰ close to the river mouth and lowest value (~ −25‰) away from the river influence. The δ 15 N maximum (14.7‰) was observed near the river mouth with lower values (5.8‰) found in deeper waters away from the river mouth. Overall, there was a general decrease of 13 C and δ 15 N values from shallow water to deeper water. There was higher δ 15 N value dispersion (std. Dev. ±3.4‰) compared to δ 13 C values with std. Dev.±1.2‰. These values also varied with seasons, a phenomenon showing significant influence of land run off on the lake elemental distribution, carbon and nitrogen in particular.

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“…Despite the episodes of flooding, low flows tend to subsequently punctuate the basin's hydrology often for long periods of time. Severe droughts in the Lake Victoria basin can be expected on average about every seven to eight years during the hot dry season from December to February [35]. According to Otieno and Awange [36], these droughts affected power production with resulting economic losses.…”

Section: Study Area and Data Seriesmentioning

confidence: 99%

“…According to Otieno and Awange [36], these droughts affected power production with resulting economic losses. According to Awange et al [35], Lake Victoria and its environment is more recently under threat from declining water levels, which has had a number of social and economic effects.…”

Section: Study Area and Data Seriesmentioning

confidence: 99%

Uncertainties in Flow-Duration-Frequency Relationships of High and Low Flow Extremes in Lake Victoria Basin

Onyutha

Willems

2013

Water

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This paper focuses on uncertainty analysis to aid decision making in applications of statistically modeled flow-duration-frequency (FDF) relationships of both daily high and low flows. The analysis is based on 24 selected catchments in the Lake Victoria basin in Eastern Africa. The FDF relationships were derived for aggregation levels in the range 1-90 days for high flows and 1-365 days for low flows. The validity of the projected FDF quantiles for high return periods T was checked using growth factor curves. Monte Carlo simulations were used to construct confidence intervals CI on both the estimated Ts for given flows and the estimated FDF quantiles for given T. The average bias of the modeled T of high and low flows are for all catchments and Ts up to 25 years lower than 8%. Despite this relatively small average bias in the modeled T, the limits of the CI on the modeled 25-year flows go up to more than 100% for high flows and more than 150% for low flows. The assessed FDF relationships and accompanied uncertainties are useful for various types of risk based water engineering and water management applications related to floods and droughts.

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Frequency and severity of drought in the Lake Victoria region (Kenya) and its effects on food security

Cited by 55 publications

References 8 publications

Falling Lake Victoria water levels: Is climate a contributing factor?

Falling Lake Victoria water levels: Is climate a contributing factor?

Significance of terrestrial inflows to carbon and nitrogen distribution in the Lake Victoria surface water

Uncertainties in Flow-Duration-Frequency Relationships of High and Low Flow Extremes in Lake Victoria Basin

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