Wyniki wyszukiwania - Biblioteka Nauki

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Assessing the intra-annual variability of agricultural soil losses: a RUSLE application in Nord-Pas-de-Calais, France

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Nouaim W. , Rambourg D. , Merzouki M. , El Harti A. , Karaoui I.

Journal of Water and Land Development

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2022

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tom no. 52

210--220

EN

The control of water erosion is an important economic and societal challenge. Reduction of the agronomic potential of the parcels, muddy flows, siltation of dams are harmful consequences that mobilize farmers, water managers, local authorities and scientific researchers. This study focuses on mapping and quantifying seasonal soil losses in the territory of the former Nord-Pas-de-Calais administrative region, using the Revised Universal Soil Loss Equation (RUSLE) which incorporates five factors: rainfall erosivity, soil erodibility, topography, land use and erosion control practices. The seasonal (3-months) time scale is chosen to better account for the parameters governing the soil water erosion, especially rainfall and vegetation cover, that show great asynchronous intra-annual variability. Also, high resolution data concerning agricultural plots allows to evaluate which type of culture are the more subject to soil losses. In Nord-Pas-de-Calais, water erosion occurs almost ubiquitously, but the areas characterized by steep slopes are the most at risk (Artois Hills and Flanders), with loss rates up to 54 t∙ha-1∙y-1. The majority of erosion occurs during fall (46% of the computed annual losses of 1.69∙Mt), on plots left bare after harvest (especially corn and beets crops). The study also demonstrates that extending the intercrop technique over the region, and therefore maintaining a fall and winter cover, could reduce the soil losses by 37%.

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Use of GIS, Remote Sensing and Analytical Hierarchy Process for Groundwater Potential Assessment in an Arid Region – A Case Study

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Jari A. , Bachaoui E. M. , Jellouli A. , El Harti A. , Khaddari A. , El Jazouli A.

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tom Vol. 23, iss. 5

234--255

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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The estimation of water erosion with RUSLE and deposition model : A case study of the Bin El-Ouidane dam catchment area (High Atlas, Morocco)

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Nouaim W. , Rambourg D. , El Harti A. , Ettaqy A. , Merzouki M. , Karaoui I.

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tom no. 58

136--147

EN

Water erosion is a critical issue for Morocco, especially in its semi-arid regions, where climatic and edaphic conditions only allow erratic soil formation and vegetation growth. Therefore, water erosion endangers human activity both directly (loss of arable land, landslides, mudflows) and indirectly (siltation of dams, river pollution). This study is part of the Kingdom’s effort to assess the risk of water erosion in its territory. It is dedicated to the Bin El-Ouidane dam water catchment, one of the biggest water storage facilities in the country, located in the High Atlas Mountains. The poorly developed soils are very sensitive to erosion in this mountainous area that combines steep slopes and sparse vegetation cover. The calculation of soil losses is carried out with the RUSLE model and corrected by estimating areas of deposition based on the unit stream power theory. This method produces a mean erosion rate of around 6.3 t·ha-1·y-1, or an overall annual loss of 4.1 mln t, consistently with the siltation rate of the dam. Primary risk areas (erosion rates > 40 t·ha-1·y-1) account for 54% of the total losses, while they cover only 7% of the catchment. This distribution of the soil losses also shows that the erosion risk is mainly correlated to slope, directing the means of control toward mechanical interventions.

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A Comparative Analysis of Analytical Hierarchy Process and Fuzzy Logic Modeling in Flood Susceptibility Mapping in the Assaka Watershed, Morocco

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Khaddari A. , Jari A. , Chakiri S. , El Hadi H. , Labriki A. , Hajaj S. , Goumghar L. , El Harti A. , Abioui M.

Journal of Ecological Engineering

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2023

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tom Vol. 24, nr 8

62--83

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.