[ Utilisation des images satellitaires du Landsat dans l’étude de la dégradation des berges des oueds : exemple des berges des oueds Rdat, Zat et Tensift lors de la crue de Novembre 2014 (Marrakech, Maroc) ]
Volume 27, Issue 1, October 2016, Pages 119–129
Mohamed AIT MLOUK1, Abdellah Algouti2, Ahmed Algouti3, and Zouhair OURHZIF4
1 Departement of geology, Faculty of science, Cadi Ayyad University, Morocco
2 Department of Geology, University of Cadi Ayyad, Faculty of Sciences Semlalia, GEOBASSMA Laboratory, Marrakesh, Morocco
3 Department of Geology, University of Cadi Ayyad, Faculty of Sciences Semlalia, GEOBASSMA Laboratory, Marrakesh, Morocco
4 Departement of geology, Faculty of science, Cadi Ayyad University, Morocco
Original language: French
Copyright © 2016 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The evolution of the riversides of wadis, Rdat, Zat and Tensift, depends, principally, on the intensity of floods and inundations generated by torrential rains slaughtered at the level of north mountainside of High - Atlas of Marrakech. The climatic conditions makes of the valleys of the wadis studied favorable zones to floods and to the degradation of the soil. From 21 to 23 November 2014, violent torrential storms, attaining 250 mm in few hours, beat down on the very high peaks of High - Atlas of Marrakech. They have resulted in impressive floods of different wadis that originate in high altitudes. Hurtling down the slopes up to the plains of the Haouz, the Muddy Waters, at high load solid, have carted the soils, trees, crops, houses and road infrastructure.The riversides of the wadis have not escaped this destruction. This degradation of soils, orchards and olive groves can be observed and analyzed by the satellite images and the field studies. As well, we proceeded to a treatment of images with the GIS tools using satellite images of Google Earth at high resolution and the Landsat images(missions of October and December 2014) with a resolution of 30m and 15m (panchromatic band). To highlight the vegetative cover of alluvial plains and its evolution in bare soil during the flood, we have represented the bands the ratios 6/7, 6/5 and 4/2 respectively in red, green and blue using the software ENVI. The analysis of the risk linked to the degradation of the banks of wadis in the study area, revealed three main processes of degradation; the erosion due to the current under the effect of the water, the landslide in mass after a quick drop in the water level and the collapse. The results obtained are very interesting and can be very useful for the understanding and the good management of water hazards and more specifically to the phenomenon of soil degradation.
Author Keywords: floods, Landsat images, degradation, wadis, riversides, vegetation cover, bare soil, Marrakech, Morocco.
Volume 27, Issue 1, October 2016, Pages 119–129
Mohamed AIT MLOUK1, Abdellah Algouti2, Ahmed Algouti3, and Zouhair OURHZIF4
1 Departement of geology, Faculty of science, Cadi Ayyad University, Morocco
2 Department of Geology, University of Cadi Ayyad, Faculty of Sciences Semlalia, GEOBASSMA Laboratory, Marrakesh, Morocco
3 Department of Geology, University of Cadi Ayyad, Faculty of Sciences Semlalia, GEOBASSMA Laboratory, Marrakesh, Morocco
4 Departement of geology, Faculty of science, Cadi Ayyad University, Morocco
Original language: French
Copyright © 2016 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The evolution of the riversides of wadis, Rdat, Zat and Tensift, depends, principally, on the intensity of floods and inundations generated by torrential rains slaughtered at the level of north mountainside of High - Atlas of Marrakech. The climatic conditions makes of the valleys of the wadis studied favorable zones to floods and to the degradation of the soil. From 21 to 23 November 2014, violent torrential storms, attaining 250 mm in few hours, beat down on the very high peaks of High - Atlas of Marrakech. They have resulted in impressive floods of different wadis that originate in high altitudes. Hurtling down the slopes up to the plains of the Haouz, the Muddy Waters, at high load solid, have carted the soils, trees, crops, houses and road infrastructure.The riversides of the wadis have not escaped this destruction. This degradation of soils, orchards and olive groves can be observed and analyzed by the satellite images and the field studies. As well, we proceeded to a treatment of images with the GIS tools using satellite images of Google Earth at high resolution and the Landsat images(missions of October and December 2014) with a resolution of 30m and 15m (panchromatic band). To highlight the vegetative cover of alluvial plains and its evolution in bare soil during the flood, we have represented the bands the ratios 6/7, 6/5 and 4/2 respectively in red, green and blue using the software ENVI. The analysis of the risk linked to the degradation of the banks of wadis in the study area, revealed three main processes of degradation; the erosion due to the current under the effect of the water, the landslide in mass after a quick drop in the water level and the collapse. The results obtained are very interesting and can be very useful for the understanding and the good management of water hazards and more specifically to the phenomenon of soil degradation.
Author Keywords: floods, Landsat images, degradation, wadis, riversides, vegetation cover, bare soil, Marrakech, Morocco.
Abstract: (french)
L’évolution des berges des oueds, Rdat, Zat et Tensift, dépend, essentiellement, de l’intensité des crues et des inondations générées par des averses abattus au niveau de versant nord du Haut-Atlas de Marrakech. Les conditions climatiques dans la région font des vallées des oueds étudiées des zones favorables aux crues et à la dégradation du sol. Du 21 au 23 novembre 2014, de violents orages diluviens, atteignant 250 mm en quelques heures, se sont abattus sur les très hauts sommets du Haut-Atlas de Marrakech. Ils ont entraîné des inondations et d'impressionnantes crues des différents oueds qui prennent naissance dans les hautes altitudes. Dévalant les pentes jusqu'aux plaines du Haouz, les eaux boueuses, à forte charge solide, ont charrié les sols, les arbres, les cultures, les maisons et les infrastructures routières. Les berges des oueds n’ont pas échappé à cette destruction. Cette dégradation des sols, des vergers et d’oliveraies peut être observée et analysée par les images satellitaires et les études de terrain. Ainsi, nous avons procédé à un traitement des images à l’aide d’outils de SIG en utilisant des images satellitaires, à haute résolution et des images Landsat avec une résolution de 30m (missions d’octobre 2014 et de décembre 2014). Pour mettre en évidence le couvert végétal des plaines alluviales et son évolution en sol nu lors de la crue, nous avons représenté les bands ratios 6/7, 6/5 et 4/2 respectivement en rouge, vert et bleu à l’aide du logiciel ENVI. L’analyse du risque lié à de la dégradation des berges dans la région d’étude, a révélé trois principaux processus de dégradation ; l’érosion due au courant sous l’action de l’eau, le glissement en masse après une décrue rapide et l’éboulement ou l’effondrement par sapement. Les résultats obtenus sont très intéressants et peuvent être d’une très grande utilité pour la compréhension et la bonne gestion des risques hydriques et plus précisément le phénomène de dégradation des sols.
Author Keywords: crues, inondations, images Landsat, dégradations, oueds, berges, Zat, Rdat, Tensift, Marrakech.
How to Cite this Article
Mohamed AIT MLOUK, Abdellah Algouti, Ahmed Algouti, and Zouhair OURHZIF, “Use of Landsat satellite images in the study of the degradation of the riversides of wadis: example of the riversides of wadis Rdat, Zat and Tensift during the flood of November, 2014 (Marrakech, Morocco),” International Journal of Innovation and Scientific Research, vol. 27, no. 1, pp. 119–129, October 2016.
