الفهرس 
INTRODUCTION AND LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
ABSTRACT
Coastal hazards are of high concern because of their adverse effects or even catastrophic impacts. These hazards, either natural or human induced, constrain development prospective and endanger lives, properties and resources in the coastal zones, such as the area under study in the northwest of Sinai. Analysis and evaluation of coastal hazards is a mandatory task for proper and secured development where necessary protective and controlling actions are proposed.
The basic objective of this thesis is to investigate, analyze, and evaluate some hydrogeochemical, hydrogeological and meteorological hazards at northwestern coast of Sinai. An approach has been applied that integrates system characterization into hazard evaluation which functions weighting / rating indices techniques, numerical modeling and empirical formulation.
The study is based on results of literature review, field and laboratory work (39 groundwater samples have been sampled and analyzed for major cations, major anions, 18 O and 2H isotopic values), statistical treatment, numerical modeling, indices evaluation and categorization, GIS overlay and mapping.
The hydrogeological characteristics of the system ( including geomorphological, lithostratigraphic and groundwater conditions) and its hydrogeochemical ones (including ions distribution, ion dominance, water types , principle components, origin of salinity, its evolution and modification processes,...etc..) have been determined and isotopically insighted.
The results of characterization are fed into the hazard analysis processes conducted in this work, which include: hazard of groundwater consumption (drinking, irrigation, construction), soil salinization, sea water intrusion , contaminant transport in groundwater, sea water rise and coastal erosion, extreme rainfall and flash flood. The attributes of the different hazards are rated, weighed and mathematically interrelated in an overall hazard values which are mapped to locate the areas of high hazard potential, this is important for proposing protective and early preparedness measures to secure development processes in the study area.
The total salinity of the study groundwater varies in a wide range (from 692 ppm to 9384ppm). Two major hydrochemical facies exist , (a) the Cl-Na and SO4- Na brackish water that dominates more than 90% of the samples reflecting a developed stage of salinity evolution under the effects of marine salts dissolution, surface evaporation before infiltration, cation exchange and Sabkha soil water contribution , (b) the HCO3-Ca fresh water that dominates less than 10% of the samples reflecting an early stages of mineralization and are located close to El-Salam Canal where surface water from the canal seeps to dilute the saline water in the aquifer.
The 18O and 2H isotpic content revealed that the predominant recharging source of the groundwater under study is meteoric water. Rain water falls on the coastal and inland sand dunes and seeps to cover and bond Sabkha deposits in the depression between sand dunes. The bonding water leaks to the aquifer with salts concentrated through dissolution of marine salts from Sabkhas.
The high salinity and major ions concentration render about 90% of the collected groundwater samples posing health hazard for human drinking, about 31% and 85% posing hazard for horses and poultry, respectively. Based on Water Quality Index (WQI) for irrigation; about 59% of the sample posing serious hazard when using in irrigation.
The risk index of the soil salinity indicates that there is soil degradation potential at zones of evaporates and Sabkha deposits due to dissolution by infiltrated water and deposition by evaporation.
The estimated GALDIT index that reflects the vulnerability for seawater intrusion shows that, about 71% of the study area is of low seawater intrusion vulnerability and about 29% is of medium vulnerability as a result of marine water associating Sabkha.
Numerical Modeling (using MODFLOW package with MT3D module) of Lead and chromium spill leak and transfer into groundwater revealed that retardation factor has the major control on their migration, and that Lead is less retarded and more distance migrated compared to chromium.
The Coastal Vulnerability Index (CVI), is calculated in the study area to explore its potentiality to stand against the hazards of erosion due to rising sea water level. An overall coastal vulnerability index (CVI ) in the range ( from 7.9 to 17.7), has been calculated for the coastal zone under study , which is categorized as very high coastal vulnerability to sea level rise and erosion effects.
The extreme rainfall event analysis has been performed using the analytical parametric methods. The relationships between Magnitudes of Maximum Probable Rainfall on one side and the Non Exceedence Probabilities and different Return Periods on the other side have been constructed and mathematically fitted by equation, that can be used for prediction.
The flash flood potential index (FFPI) was developed by GIS raster surfaces for each of the four inputs (slope, land use/land cover, soil type/texture, and vegetation cover or density). The areas of highest flash flood risk are located close to the northwestern zone and at some scattered areas in the southern part of the investigated area. The most critical parameters for flash flood potentiality in the study area are: land use, soil texture and the vegetation cover.