Water Erosion and Environmental Dynamics in Tlagh and El Abed watersheds (Eastern Morocco). Geomatics Approaches. Thesis for obtaining a doctorate degree. Faculty of Humanities. University Mohammed First. Oujda, 421 p. (In Arabic).
Creators: name: MOUADILI, Omar
Publisher: name: figshare
Year: 2022
Subjects: subject: 90999 Geomatic Engineering not elsewhere classified
subject: FOS: Environmental engineering
subject: Geography
subject: Physical Geography

description: Water erosion is one of the most natural hazards with obvious and detrimental damage to the surface of the land and a serious threat to the environmental balance, in particular in arid and semi-arid environments. It is also one of the important most challenges associated with basins and rural areas. Erosion leads to the transfer of solid materials to valleys, depressions and dams. The Taourirt-Guercif corridor has undergone significant spatial changes which have led to demographic challenges, environmental and spatial imbalances which have modified the characteristics of the geographical landscape. This is manifested by the dominance of forms of water erosion and the degradation of the vegetation. By addressing erosion quantitatively and qualitatively, the General Soil Loss Equation (USLE) showed that the average soil loss is 37.64 tonnes/ha/year for the Wadi Tlagh basin and 32.23 tonnes/ha/year for El-Abed wadi basin. It was also concluded through the PAP/RAC model that important areas recorded a high potential for erosion. Direct field measurements using a RAMP-type rain simulator showed that the average rate of sheet erosion in 37 experimental plots is 39.18 tonnes/ha/year. Topographic surveys to measure localized erosion, characteristic of some places, have shown that the average grubbing up in only three sites is 1349 tonnes/ha/year. The study of the hydrological behavior of several types of exploitation concluded that these surfaces have a different flow coefficient between them; and this difference can be useful for land use planning through the orientation of the exploitation modes. These measurements have shown the types of exploitation from which runoff can start quickly, and thus the farmer can be made aware of the modes of exploitation that can be followed to reduce the risk of erosion. The role of natural characteristics and spatial distribution in degradation aspects and in activating environmental dynamics has also been highlighted. The slope and orientation affect the nature of the runoff, and the drought contributes to the fragility of the land by preventing the natural growth of plants, thus becoming weak, more degraded and less intense. Faced with the degradation of this environmental space, the human factors activating this dynamic were diagnosed, and land use patterns as well as the role of state projects in the management of these resources were discussed. One of the results of this on environmental media is that changes in these exploitation methods have an impact and control degradation by accelerating its mechanisms. Given this situation of degraded areas threatened by continuous water erosion, and on the basis of the results obtained, it has become necessary to reconsider the forms of intervention in these fragile and paralyzed environments; and these precious resources that nature does not preserve by itself must be preserved by man giveb their fragility. Nature creates these ecological balances, but man helps break and violate them.