The response of phytoplankton and zooplankton to river damming in three cascading reservoirs of the Tana River, Kenya

2016 ◽  
Vol 21 (2) ◽  
pp. 114-132 ◽  
Author(s):  
Eric Ochieng Okuku ◽  
Mwakio Tole ◽  
Linet Imbayi Kiteresi ◽  
Steven Bouillon
Keyword(s):  
River Damming ◽  
Tana River ◽  
Cascading Reservoirs

scholarly journals Heatwaves in Kenya 1987–2016: Facts from CHIRTS High Resolution Satellite Remotely Sensed and Station Blended Temperature Dataset

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 37
Author(s):  
Martial Amou ◽  
Amatus Gyilbag ◽  
Tsedale Demelash ◽  
Yinlong Xu
Keyword(s):  
High Resolution ◽  
Adaptation Strategies ◽  
Reference Period ◽  
The West ◽  
Tana River ◽  
Short Period ◽  
The World ◽  
Northern Side ◽  
Data Source

As global temperatures continue to rise unabated, episodes of heat-related catastrophes across the world have intensified. In Kenya, heatwave phenomena and their associated impacts are ignored and neglected due to several reasons, including unreliable and inconsistent weather datasets and heatwave detection metrics. Based on CHIRTS satellite infrared estimates and station blended temperature, this study investigated the spatiotemporal distribution of the heatwave events over Kenya during 1987–2016 using the Heatwave Magnitude Index daily (HWMId). The results showed that contrary to the absence of heatwave records in official national and international disaster database about Kenya, the country experienced heatwaves ranging from less severe (normal) to deadly (super-extreme) between 1987 and 2016. The most affected areas were located in the eastern parts of the country, especially in Garissa and Tana River, and in the west-northern side around the upper side of Turkana county. It was also found that the recent years’ heatwaves were more severe in magnitude, duration, and spatial extent. The highest magnitude of the heatwaves was recorded in 2015 (HWMId = 22.64) while the average over the reference period is around 6. CHIRTS and HWMId were able to reveal and capture most critical heatwave events over the study period. Therefore, they could be used respectively as data source and detection metrics, for heatwaves disaster emergency warning over short period as well as for long-term projection to provide insight for adaptation strategies.

scholarly journals Productivity driven by Tana river discharge is spatially limited in Kenyan coastal waters

2021 ◽  
Vol 211 ◽  
pp. 105713
Author(s):  
Damaris Mutia ◽  
Stephen Carpenter ◽  
Zoe Jacobs ◽  
Fatma Jebri ◽  
Joseph Kamau ◽  
...  
Keyword(s):  
Coastal Waters ◽  
River Discharge ◽  
Tana River

scholarly journals Evaluation of the Upper Paraná River discharge controlled by reservoirs

2009 ◽  
Vol 69 (2 suppl) ◽  
pp. 707-716 ◽  
Author(s):  
EE. Souza Filho
Keyword(s):  
Paraná River ◽  
River Level ◽  
Parana River ◽  
River Damming ◽  
Discharge Rates ◽  
Historical Series ◽  
Discharge Regime ◽  
Upper Paraná River ◽  
The Relationship ◽  
Different Levels

The building of large dams in the Upper Paraná River basin altered the discharge regime at the Porto São José River section. The discharge regime has been altered since 1972, but the changes intensified after the Porto Primavera damming, in late 1998. Considering that discharge control affects the relationship between channel and floodplain, this work aimed to evaluate the intensity of the discharge control that resulted from the operation of the Porto Primavera Dam. To achieve this objective, statistical analyses were carried out based on the Porto São José Fluviometric Station historical series of river level readings and discharge, between 1964 and 2007. Results showed that the average discharge increased from 1964 to 1981 and diminished after river damming. The increase of average discharge rates was followed by an increase of the duration of higher discharges at different levels of geomorphologic and limnological importance, and the reduction of average discharge during the last observed period was followed by a disproportionate decrease in the duration of the abovementioned discharges. Moreover, it is clear that the relationship between fluviometric level and fluvial discharge changed, which implies that a certain river level reading represents a higher discharge than necessary before river damming.

scholarly journals Dissolved organic carbon lability and stable isotope shifts during microbial decomposition in a tropical river system

2015 ◽  
Vol 12 (15) ◽  
pp. 12761-12782
Author(s):  
N. Geeraert ◽  
F. O. Omengo ◽  
G. Govers ◽  
S. Bouillon
Keyword(s):  
Stable Isotope ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Isotope Composition ◽  
River System ◽  
Photochemical Oxidation ◽  
Microbial Decomposition ◽  
Tana River ◽  
Incubation Experiments ◽  
Microbial Consumption

Abstract. A significant amount of carbon is transported to the ocean as dissolved organic carbon (DOC) in rivers. During transport, it can be transformed through microbial consumption and photochemical oxidation. In dark incubation experiments with water from the Tana River, Kenya, we examined the consumption of DOC through microbial decomposition and the associated change in its carbon stable isotope composition (δ13C). In 15 of the 18 incubations, DOC concentrations decreased significantly by 10 to 60 %, with most of the decomposition taking place within the first 24–48 h. After 8 days, the remaining DOC was up to 3 ‰ more depleted in 13C compared with the initial pool, and the change in δ13C correlated strongly with the fraction of DOC remaining. We propose that the shift in δ13C is consistent with greater microbial lability of DOC originating from herbaceous C4 vegetation than DOC derived from woody C3 vegetation in the semi-arid lower Tana. The findings complement earlier data that riverine C sources do not necessarily reflect their proportion in the catchment: besides spatial distribution, also processing within the river can further influence the riverine δ13C.

scholarly journals Leptospira spp. seroprevalence in humans involved in a cross-sectional study in Garissa and Tana River Counties, Kenya

2020 ◽  
Author(s):  
Arithi Mutembei ◽  
Festus K. Mutai ◽  
Damaris Mwololo ◽  
John Muriuki ◽  
Mark Obonyo ◽  
...  
Keyword(s):  
Case Fatality ◽  
Cross Sectional Study ◽  
Wilcoxon Test ◽  
Categorical Variables ◽  
P Value ◽  
Continuous Variables ◽  
Sectional Study ◽  
Test Statistic ◽  
Cross Sectional ◽  
Tana River

AbstractIntroductionLeptospirosis is a neglected bacterial zoonotic infection caused by spirochetes of Leptospira genus. Humans get infected through direct or indirect contact with urine of infected animals or environment. It accounts for more than 300,000 severe cases annually worldwide with case fatality rates of over 30%. Costs of diagnosis and treatment for human and animals, disruption of international trade of animals and products, reduced productivity and reproductivity in animals constitute economic importance. In Kenya, leptospirosis burden is significant but under-diagnosis and under-reporting affects the awareness of the disease. This study aimed to determine and compare the sero-prevalence and factors associated with Leptospira spp. in the two counties.MethodsWe conducted a cross-sectional study that involved apparently healthy people of at least 5 years of age in randomly selected households in Garissa and Tana River Counties. Blood samples were collected and tested for Leptospira spp antibodies using IgM ELISA. Standardized structured questionnaires were administered to collect socio-demographic and exposure information. We calculated frequencies and proportions for categorical variables and odds ratios (OR) and 95% confidence interval (CI) to evaluate association between sero-positivity and exposure factors. We used Wilcoxon test to evaluate statistical difference in sero-positivity for continuous variables and calculated test statistic (H) and p-value.ResultsA total of 952 subjects were recruited into the study – these included 482 persons from Garissa and 470 from Tana River. The overall sero-prevalence was 26% [(244/952); (CI: 23% to 29%)]. Garissa County had significantly higher Leptospira spp. seroprevalence (31%, n = 147; CI: 27% to 35%) compared to Tana River County (21 %, n = 97; CI: 17% to 25%). Being a female (OR=1.6, CI: 1.2-2.2) and engaging in pastoralism (OR=2.7, CI: 1.8-3.9) were significantly associated with higher odds of Leptospira spp. seropositivity compared to being a male or working in irrigated areas. The mean altitude of residence of sero-positive patients was 73m ± 21 SD (standard deviation) above sea level and that for sero-negative was 80m ± 22 SD (H=35, p-value = 0.00).ConclusionThis study determined the seroprevalence and risk factors for Leptospira spp. exposure in Garissa and Tana River Counties, Kenya. Females in pastoral communities experience high burden of the disease. Enhanced surveillance in humans and animals and further research is required to understand the complex and multifactorial drivers of leptospirosis transmission in the two Counties.

INFORMAL DISCUSSION. A PLANNING MODEL FOR THE TANA RIVER BASIN, KENYA.

1980 ◽  
Vol 68 (1) ◽  
pp. 155-158
Author(s):  
DJ EDMONDS ◽  
MW LIDDAMENT ◽  
PA MAWER ◽  
CA CLINGAN
Keyword(s):  
River Basin ◽  
Planning Model ◽  
Tana River ◽  
Informal Discussion
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