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Doctorat
Egypte
Using And Verifying Watershed Models For Water Management In North Western Coast Zone– Egypt
Titre : Using And Verifying Watershed Models For Water Management In North Western Coast Zone– Egypt
Auteur : Abdalla, Mohamed Ahmed Ibrahem.
Etablissement de soutenance : Zagazig University
Grade : Doctor of Philosophy (PhD) in Agricultural Sciences (2021)
Résumé
Climate changes especially drought and flash floods are the major natural hazards cause of land degradation in the arid and semi-arid regions. North-Western Coast Region (NCR) of Egypt as arid region suffers from lack of rainfall most of the year except during rainfall events during the winter season which may even culminate with flash floods. This region is expose to acceleration of soil erosion and water losses causes by floods resulting in degradation of the fertile topsoil of the cultivation lands and consequently the agri-food productivity. Also, this region Suffer lack of water reservoirs and terraces construction. Hydrological models are very useful tools for simulating the effect of natural processes and management practices on soil and water resources. Hence, the present study aims to select the appropriate hydrological model through calibration and validation of KINEROS2 and ARCSWAT models with GIS interface and making sure that the model work properly under Egyptian conditions by compare simulated results with measured data during two rainfall seasons in NCR, to predict soil losses and establish the appropriate soil and water conservation strategies. The models were run using satellite image digital elevation model (DEM), Land use/cover classification and soil map as layers input in models. The obtained results revealed that, the KINEROS2 more efficient than ARCSWAT, with acceptable average values of Nash–Sutcliffe coefficient Efficiency (NSE) and the coefficient of determination (R²) were 0.89 and 0.91, respectively and relative error (RE) ranged from 1.07 % to 8.77 % for KINEROS2 in sub-catchment of Wadi Kharouba. While, NSE, R2, and RE were 0.86, 0.88 and 14.7 %, in Wadi El Raml. Thus, the KINEROS2 model was applied in watershed level where the obtained results in sub-catchment of Wadi Kharouba showed that, the total quantity of water stored into the soil of stream area was about 176,014.54 m3/ year where 84 % stored in the main stream. While the total quantity of runoff water was leaving at the outlet of watershed about 131,588.0 m3/ year. The results of runoff in overland basins ranged from 998.38 to 22,202.59 m3/year. While in Wadi El Raml ranged from 17.46 to 757.21 m3/year. Additionally, the obtained results of modeling identified the areas with a high risk of soil losses where the average value of sediment yield was 5.538 and 12.47 t/ha/year for streams and overland basins, respectively, in Wadi Kharouba while was 0.320 and 2.076 t/ha/year for streams and overland basins, respectively, in Wadi Kharouba. Hence, it’s recommended that a reservoir can be constructed inside field approximately about 200-600 m3/ha/year for using as supplementary irrigation during dry period and build terraces for storing rainwater, conserving and maximizing soil moisture in watershed. Establish semicircles to control soil erosion on the slopes and application KINEROS2 model on a large scale and generalize it to the other wadis in NCR of Egypt and used it a decision support tool to understand the implications of future climate change on the runoff and sediment loss.
Page publiée le 10 mars 2023