ISSN (Print): 2372-3076

ISSN (Online): 2372-3084

Currrent Issue: Volume 3, Number 4, 2015


Spatio-temporal Drought Characterization for the Upper Tana River Basin, Kenya Using Standardized Precipitation Index (SPI)

1Egerton University, Department of Agricultural Engineering, Kenya

2Jomo Kenyatta University of Agriculture and Technology, SWEEN

World Journal of Environmental Engineering. 2015, 3(4), 111-120
doi: 10.12691/wjee-3-4-2
Copyright © 2015 Science and Education Publishing

Cite this paper:
Raphael M. Wambua, Benedict M. Mutua, James M. Raude. Spatio-temporal Drought Characterization for the Upper Tana River Basin, Kenya Using Standardized Precipitation Index (SPI). World Journal of Environmental Engineering. 2015; 3(4):111-120. doi: 10.12691/wjee-3-4-2.

Correspondence to: Raphael  M. Wambua, Egerton University, Department of Agricultural Engineering, Kenya. Email:


Drought occurrence in the upper Tana River basin in Kenya has impacted negatively on water resources, hydro-power generation and agricultural production within the basin. Although this is an important river basin in Kenya, there is limited research work that has been done to assess and characterize drought to provide feasible mitigation measures and /or coping mechanics for water resources management. The Standardized Precipitation Index (SPI) was used to assess the spatio-temporal drought characteristics within the upper Tana River basin based on precipitation data for 41 years for eight gauging stations within the basin. The Kriging interpolation technique was applied to estimate spatially drought occurrence within the basin while the non-parametric Mann-Kendall (MK) trend test was used for trend detection. Results show that the south-eastern parts of the basin exhibit the highest drought severities while the north-western parts have the lowest drought values with averages of 2.140 and 4.065, and 2.542 and 4.812 in 1970 and 2010 respectively. The areal-extend of drought severities in both the south-eastern and north-western areas increased from 4868.7 km2 to 6880 km2, and 6163.9 km2 to 6985.5 km2 from 1970 to 2010 respectively. The drought trend increased in the south-eastern parts of the basin at 90% and 95% significant levels while no significant trend was detected in the north-western areas. The results presented in this paper are useful in formulating a drought early warning system that can be used to assist water resources managers in developing timely mitigation measures in planning and managing water resources within the basin.



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Kinetic Thermal Degradation of Cellulose, Polybutylene Succinate and a Green Composite: Comparative Study

1Laboratory of Applied Chemistry and Environment- Department of Chemistry, Faculty of Sciences, Mohammed Premier University, Oujda, Morocco

2Laboratory of Physical Chemistry of Natural Resources and Environment - Department of Chemistry, Faculty of Sciences, Mohammed Premier University, Oujda, Morocco

3The chemical measuring room - Department of Chemistry, Faculty of Sciences, Mohammed Premier University, Oujda, Morocco

World Journal of Environmental Engineering. 2015, 3(4), 95-110
doi: 10.12691/wjee-3-4-1
Copyright © 2015 Science and Education Publishing

Cite this paper:
Benarbia Abderrahim, Elidrissi Abderrahman, Aqil Mohamed, Tabaght Fatima, Tahani Abdesselam, Ouassini Krim. Kinetic Thermal Degradation of Cellulose, Polybutylene Succinate and a Green Composite: Comparative Study. World Journal of Environmental Engineering. 2015; 3(4):95-110. doi: 10.12691/wjee-3-4-1.

Correspondence to: Benarbia  Abderrahim, Laboratory of Applied Chemistry and Environment- Department of Chemistry, Faculty of Sciences, Mohammed Premier University, Oujda, Morocco. Email:


Polybutylene succinate (PBS), classed as biopolymer, was synthesized by condensation of succinic acid with a lower excess of (1, 4) butanediol. The synthesized polymer was analyzed by FTIR, RMN, DSC and ATG/ATD. Thermal degradation kinetics was investigated for cellulose, polybutylene succinate, physical blend of both polymers (cellulose (80%) + PBS (20%)) and compared with polycaprolactone by dynamic thermogravimetry, under nitrogen atmosphere from room temperature to 480 °C, at constant nominal heating rates: 5, 10 and 15 °C/min, respectively. The Kissinger, Friedman, Flynn-Ozawa-Wall and Coatse - Redfern (modified) methods were developed and the corresponding activation energies, frequency factors and reaction orders were determined.



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