Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed

Vieux Boukhaly Traore; Soussou Sambou; Mohamed Talla Cisse; Séni Tamba; Sidy Fall; Amadou Tahirou Diaw; Hyacinthe Sambou; Malanda Edmond Nimy

doi:doi:10.11648/j.ijepp.20140204.13

Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed

Vieux Boukhaly Traore, Soussou Sambou, Mohamed Talla Cisse, Séni Tamba, Sidy Fall, Amadou Tahirou Diaw, Hyacinthe Sambou, Malanda Edmond Nimy

Published in International Journal of Environmental Protection and Policy (Volume 2, Issue 4)

Received: 7 August 2014 Accepted: 20 August 2014 Published: 30 August 2014

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Abstract

For several decades, climate change and climate variability issues and their impacts on the hydrological regime of rivers have constituted a major topic for hydroclimatological sciences research and water resources planning policies. Understanding of these issues needs enough long time series of rainfall and runoff data covering a large period, and a comprehensive diagnosis of the existing trends and shifts in these time series of data. This can be done by applying robust statistical tests to relevant rainfall and runoff time annual series. The aim of this paper is to highlight the effect of climate change in the Gambia River Basin and its impacts on the availability of the water resources of this basin. To reach this objective, we have selected runoff time series of the Gambia River Basin at Mako, Kedougou Diaguéri streamgauges and rainfall time series at Koulountou’s rain gauge. Statistical tests for shift detection presented in the Khronostat software, such as Pettit, Hubert and Buishand ellipse tests are first used, Mann Kendall test for annual trend are then applied to check whether trends exist or not in these times series. When the null hypothesis of no trend is rejected, the non parametric Sen’s test is then applied to validate the Mann Kendall trend test and to estimate the magnitude of the trend and its direction. Tests for homogeneity show an increasing shift for rainfall time series of Koulountou raingauge and for runoff time series of Mako and Diaguéri and a decreasing shift for Kedougou streamgauge. According to the Mann Kendall trend test, there is an upward trend for Koulountou rainfall time series, and Mako and Diaguéri runoff time series, and a downward trend for Kedougou annual runoff time series. The Buishand ellipse and the Hubert test indicate generally the same year of the beginning of the shift. Interesting perspectives for decision makers in evaluation and precise management of water resources and water projects in the Gambia River basin are offered as well.

Published in	International Journal of Environmental Protection and Policy (Volume 2, Issue 4)
DOI	10.11648/j.ijepp.20140204.13
Page(s)	138-146
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2014. Published by Science Publishing Group

Keywords

Climate Variability, Hydrometeorological Data, Statistical Hydrology, Water Resources, Watershed, Gambia River, Management, Decision Making, Country Planning

References

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APA Style

Vieux Boukhaly Traore, Soussou Sambou, Mohamed Talla Cisse, Séni Tamba, Sidy Fall, et al. (2014). Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed. International Journal of Environmental Protection and Policy, 2(4), 138-146. https://doi.org/10.11648/j.ijepp.20140204.13

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ACS Style

Vieux Boukhaly Traore; Soussou Sambou; Mohamed Talla Cisse; Séni Tamba; Sidy Fall, et al. Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed. Int. J. Environ. Prot. Policy 2014, 2(4), 138-146. doi: 10.11648/j.ijepp.20140204.13

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AMA Style

Vieux Boukhaly Traore, Soussou Sambou, Mohamed Talla Cisse, Séni Tamba, Sidy Fall, et al. Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed. Int J Environ Prot Policy. 2014;2(4):138-146. doi: 10.11648/j.ijepp.20140204.13

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@article{10.11648/j.ijepp.20140204.13,
  author = {Vieux Boukhaly Traore and Soussou Sambou and Mohamed Talla Cisse and Séni Tamba and Sidy Fall and Amadou Tahirou Diaw and Hyacinthe Sambou and Malanda Edmond Nimy},
  title = {Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed},
  journal = {International Journal of Environmental Protection and Policy},
  volume = {2},
  number = {4},
  pages = {138-146},
  doi = {10.11648/j.ijepp.20140204.13},
  url = {https://doi.org/10.11648/j.ijepp.20140204.13},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijepp.20140204.13},
  abstract = {For several decades, climate change and climate variability issues and their impacts on the hydrological regime of rivers have constituted a major topic for hydroclimatological sciences research and water resources planning policies. Understanding of these issues needs enough long time series of rainfall and runoff data covering a large period, and a comprehensive diagnosis of the existing trends and shifts in these time series of data. This can be done by applying robust statistical tests to relevant rainfall and runoff time annual series. The aim of this paper is to highlight the effect of climate change in the Gambia River Basin and its impacts on the availability of the water resources of this basin. To reach this objective, we have selected runoff time series of the Gambia River Basin at Mako, Kedougou Diaguéri streamgauges and rainfall time series at Koulountou’s rain gauge. Statistical tests for shift detection presented in the Khronostat software, such as Pettit, Hubert and Buishand ellipse tests are first used, Mann Kendall test for annual trend are then applied to check whether trends exist or not in these times series. When the null hypothesis of no trend is rejected, the non parametric Sen’s test is then applied to validate the Mann Kendall trend test and to estimate the magnitude of the trend and its direction. Tests for homogeneity show an increasing shift for rainfall time series of Koulountou raingauge and for runoff time series of Mako and Diaguéri and a decreasing shift for Kedougou streamgauge. According to the Mann Kendall trend test, there is an upward trend for Koulountou rainfall time series, and Mako and Diaguéri runoff time series, and a downward trend for Kedougou annual runoff time series. The Buishand ellipse and the Hubert test indicate generally the same year of the beginning of the shift. Interesting perspectives for decision makers in evaluation and precise management of water resources and water projects in the Gambia River basin are offered as well.},
 year = {2014}
}

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TY  - JOUR
T1  - Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed
AU  - Vieux Boukhaly Traore
AU  - Soussou Sambou
AU  - Mohamed Talla Cisse
AU  - Séni Tamba
AU  - Sidy Fall
AU  - Amadou Tahirou Diaw
AU  - Hyacinthe Sambou
AU  - Malanda Edmond Nimy
Y1  - 2014/08/30
PY  - 2014
N1  - https://doi.org/10.11648/j.ijepp.20140204.13
DO  - 10.11648/j.ijepp.20140204.13
T2  - International Journal of Environmental Protection and Policy
JF  - International Journal of Environmental Protection and Policy
JO  - International Journal of Environmental Protection and Policy
SP  - 138
EP  - 146
PB  - Science Publishing Group
SN  - 2330-7536
UR  - https://doi.org/10.11648/j.ijepp.20140204.13
AB  - For several decades, climate change and climate variability issues and their impacts on the hydrological regime of rivers have constituted a major topic for hydroclimatological sciences research and water resources planning policies. Understanding of these issues needs enough long time series of rainfall and runoff data covering a large period, and a comprehensive diagnosis of the existing trends and shifts in these time series of data. This can be done by applying robust statistical tests to relevant rainfall and runoff time annual series. The aim of this paper is to highlight the effect of climate change in the Gambia River Basin and its impacts on the availability of the water resources of this basin. To reach this objective, we have selected runoff time series of the Gambia River Basin at Mako, Kedougou Diaguéri streamgauges and rainfall time series at Koulountou’s rain gauge. Statistical tests for shift detection presented in the Khronostat software, such as Pettit, Hubert and Buishand ellipse tests are first used, Mann Kendall test for annual trend are then applied to check whether trends exist or not in these times series. When the null hypothesis of no trend is rejected, the non parametric Sen’s test is then applied to validate the Mann Kendall trend test and to estimate the magnitude of the trend and its direction. Tests for homogeneity show an increasing shift for rainfall time series of Koulountou raingauge and for runoff time series of Mako and Diaguéri and a decreasing shift for Kedougou streamgauge. According to the Mann Kendall trend test, there is an upward trend for Koulountou rainfall time series, and Mako and Diaguéri runoff time series, and a downward trend for Kedougou annual runoff time series. The Buishand ellipse and the Hubert test indicate generally the same year of the beginning of the shift. Interesting perspectives for decision makers in evaluation and precise management of water resources and water projects in the Gambia River basin are offered as well.
VL  - 2
IS  - 4
ER  -

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Author Information

Vieux Boukhaly Traore

Hydraulics Laboratory and Fluid Mechanics (LHMF), Faculty of Science and Technology, Department of Physics, University Cheikh Anta Diop (UCAD) BP 5005, Dakar-Fann, Senegal
Soussou Sambou

Hydraulics Laboratory and Fluid Mechanics (LHMF), Faculty of Science and Technology, Department of Physics, University Cheikh Anta Diop (UCAD) BP 5005, Dakar-Fann, Senegal
Mohamed Talla Cisse

University of Thies, Facultty of Technological Sciences, Department of Experimental Sciences, Thies, Senegal
Séni Tamba

Thies Polytechnic School, Department of Civil Engineering, PB 10, Thies, Senegal
Sidy Fall

Office Lake Guiers Company for the Development and Operation of Lands Senegal River Delta and the Valleys of the Senegal River and Falémé (SAED), Saint Louis, Senegal
Amadou Tahirou Diaw

Teaching Laboratory and Research in Geomatics (LERG), Faculty of letters and Social Sciences, Department of Geography, University Campus of Polytechnic High School of Dakar BP 5005 Dakar-Fann, Senegal
Hyacinthe Sambou

Teaching Laboratory and Research in Geomatics (LERG), Faculty of letters and Social Sciences, Department of Geography, University Campus of Polytechnic High School of Dakar BP 5005 Dakar-Fann, Senegal
Malanda Edmond Nimy

Hydraulics Laboratory and Fluid Mechanics (LHMF), Faculty of Science and Technology, Department of Physics, University Cheikh Anta Diop (UCAD) BP 5005, Dakar-Fann, Senegal

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Vieux Boukhaly Traore, Soussou Sambou, Mohamed Talla Cisse, Séni Tamba, Sidy Fall, et al. (2014). Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed. International Journal of Environmental Protection and Policy, 2(4), 138-146. https://doi.org/10.11648/j.ijepp.20140204.13

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ACS Style

Vieux Boukhaly Traore; Soussou Sambou; Mohamed Talla Cisse; Séni Tamba; Sidy Fall, et al. Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed. Int. J. Environ. Prot. Policy 2014, 2(4), 138-146. doi: 10.11648/j.ijepp.20140204.13

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AMA Style

Vieux Boukhaly Traore, Soussou Sambou, Mohamed Talla Cisse, Séni Tamba, Sidy Fall, et al. Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed. Int J Environ Prot Policy. 2014;2(4):138-146. doi: 10.11648/j.ijepp.20140204.13

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@article{10.11648/j.ijepp.20140204.13,
  author = {Vieux Boukhaly Traore and Soussou Sambou and Mohamed Talla Cisse and Séni Tamba and Sidy Fall and Amadou Tahirou Diaw and Hyacinthe Sambou and Malanda Edmond Nimy},
  title = {Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed},
  journal = {International Journal of Environmental Protection and Policy},
  volume = {2},
  number = {4},
  pages = {138-146},
  doi = {10.11648/j.ijepp.20140204.13},
  url = {https://doi.org/10.11648/j.ijepp.20140204.13},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijepp.20140204.13},
  abstract = {For several decades, climate change and climate variability issues and their impacts on the hydrological regime of rivers have constituted a major topic for hydroclimatological sciences research and water resources planning policies. Understanding of these issues needs enough long time series of rainfall and runoff data covering a large period, and a comprehensive diagnosis of the existing trends and shifts in these time series of data. This can be done by applying robust statistical tests to relevant rainfall and runoff time annual series. The aim of this paper is to highlight the effect of climate change in the Gambia River Basin and its impacts on the availability of the water resources of this basin. To reach this objective, we have selected runoff time series of the Gambia River Basin at Mako, Kedougou Diaguéri streamgauges and rainfall time series at Koulountou’s rain gauge. Statistical tests for shift detection presented in the Khronostat software, such as Pettit, Hubert and Buishand ellipse tests are first used, Mann Kendall test for annual trend are then applied to check whether trends exist or not in these times series. When the null hypothesis of no trend is rejected, the non parametric Sen’s test is then applied to validate the Mann Kendall trend test and to estimate the magnitude of the trend and its direction. Tests for homogeneity show an increasing shift for rainfall time series of Koulountou raingauge and for runoff time series of Mako and Diaguéri and a decreasing shift for Kedougou streamgauge. According to the Mann Kendall trend test, there is an upward trend for Koulountou rainfall time series, and Mako and Diaguéri runoff time series, and a downward trend for Kedougou annual runoff time series. The Buishand ellipse and the Hubert test indicate generally the same year of the beginning of the shift. Interesting perspectives for decision makers in evaluation and precise management of water resources and water projects in the Gambia River basin are offered as well.},
 year = {2014}
}

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TY  - JOUR
T1  - Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed
AU  - Vieux Boukhaly Traore
AU  - Soussou Sambou
AU  - Mohamed Talla Cisse
AU  - Séni Tamba
AU  - Sidy Fall
AU  - Amadou Tahirou Diaw
AU  - Hyacinthe Sambou
AU  - Malanda Edmond Nimy
Y1  - 2014/08/30
PY  - 2014
N1  - https://doi.org/10.11648/j.ijepp.20140204.13
DO  - 10.11648/j.ijepp.20140204.13
T2  - International Journal of Environmental Protection and Policy
JF  - International Journal of Environmental Protection and Policy
JO  - International Journal of Environmental Protection and Policy
SP  - 138
EP  - 146
PB  - Science Publishing Group
SN  - 2330-7536
UR  - https://doi.org/10.11648/j.ijepp.20140204.13
AB  - For several decades, climate change and climate variability issues and their impacts on the hydrological regime of rivers have constituted a major topic for hydroclimatological sciences research and water resources planning policies. Understanding of these issues needs enough long time series of rainfall and runoff data covering a large period, and a comprehensive diagnosis of the existing trends and shifts in these time series of data. This can be done by applying robust statistical tests to relevant rainfall and runoff time annual series. The aim of this paper is to highlight the effect of climate change in the Gambia River Basin and its impacts on the availability of the water resources of this basin. To reach this objective, we have selected runoff time series of the Gambia River Basin at Mako, Kedougou Diaguéri streamgauges and rainfall time series at Koulountou’s rain gauge. Statistical tests for shift detection presented in the Khronostat software, such as Pettit, Hubert and Buishand ellipse tests are first used, Mann Kendall test for annual trend are then applied to check whether trends exist or not in these times series. When the null hypothesis of no trend is rejected, the non parametric Sen’s test is then applied to validate the Mann Kendall trend test and to estimate the magnitude of the trend and its direction. Tests for homogeneity show an increasing shift for rainfall time series of Koulountou raingauge and for runoff time series of Mako and Diaguéri and a decreasing shift for Kedougou streamgauge. According to the Mann Kendall trend test, there is an upward trend for Koulountou rainfall time series, and Mako and Diaguéri runoff time series, and a downward trend for Kedougou annual runoff time series. The Buishand ellipse and the Hubert test indicate generally the same year of the beginning of the shift. Interesting perspectives for decision makers in evaluation and precise management of water resources and water projects in the Gambia River basin are offered as well.
VL  - 2
IS  - 4
ER  -

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