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EN
The Assaka watershed is one of the largest watersheds in the Guelmim region in southern Morocco. It is frequently exposed to the many flooding events that can be responsible for many costly human and material damages. This work illustrates a decision-making methodology based on Analytical Hierarchy Process (AHP) and Fuzzy Logic Modelling (FLM), in the order to perform a useful flood susceptibility mapping in the study area. Seven decisive factors were introduced, namely, flow accumulation, distance to the hydrographic network, elevation, slope, LULC, lithology, and rainfall. The susceptibility maps were obtained after normalization and weighting using the AHP, while after Fuzzification as well as the application of fuzzy operators (OR, SUM, PRODUCT, AND, GAMMA 0.9) for the fuzzy logic methods. Thereafter, the flood susceptibility zones were distributed into five flood intensity classes with very high, high, medium, low, and, very low susceptibility. Then validated by field observations, an inventory of flood-prone sites identified by the Draa Oued Noun Hydraulic Watershed Agency (DONHBA) with 71 carefully selected flood-prone sites and GeoEye-1 satellite images. The assessment of the mapping results using the ROC curve shows that the best results are derived from applying the fuzzy SUM (AUC = 0.901) and fuzzy OR (AUC = 0.896) operators. On the other hand, the AHP method (AUC = 0.893) shows considerable mapping results. Then, a comparison of the two methods of SUM fuzzy logic and AHP allowed considering the two techniques as complementary to each other. They can accurately model the flood susceptibility of the Assaka watershed. Specifically, this area is characterized by a high to very high risk of flooding, which was estimated at 67% and 30% of the total study area coverage using the fuzzy logic (SUM operator) and the AHP methods, respectively. Highly susceptible flood areas require immediate action in terms of planning, development, and land use management to avoid any dramatic disaster.
EN
Soil loss is a problem that contributes to land degradation in many countries and Morocco is no exception. Our study focuses on water erosion in Korifla, a sub-basin of the Bouregreg watershed in northern Morocco. The objective is to quantify erosion using the RUSLE method which is based on five factors: Runoff erosivity, soil erodibility, cover factor, topography and conservation practices. These are processed by remote sensing and a geographic information system. The soil loss map shows that on an area of 1838 km2, erosion is estimated to be between 0.00 t/ha/year and 27.61 t/ha/year. The cumulative effect of the factors R, K, LS, C, and P are both the origin of this erosion and its spatial distribution.
EN
This research aims to evaluate the groundwater potentiality in the arid region “Telmzoun” located in the south of Morocco using the analytical hierarchy process (AHP) model of multi-criteria analysis in conjunction with geographic information system (GIS) and remote sensing techniques. The used methodology to generate the groundwater potential map starts with the preparation of thematic layers of different factors influencing the existence of groundwater, such as precipitation, lithology, geomorphology, lineament density, drainage density, slope, in addition to the proximity of the hydrographic network. Groundwater potential map was prepared using relative weights derived from the AHP. The results were mapped on ArcGIS 10.2 and validated using the existing borehole data and the ROC curve. The accuracy of the generated map reached over 70%. It represents five classes of groundwater potential that are as follows: very high potential areas consisting of 10.5% (2.14 km2), high potential representing a rate of 27.2% (5.53 km2), moderate potential areas consisting of 30% (6.06 km2), low potential 20.5% (4.17 km2) and very low potential areas showing a rate of 11.8% (2.40 km2) of the total study area. The results obtained are satisfactory and consist of a guide map to be used effectively in direct future groundwater exploration campaigns and to minimize various field costs.
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