Mohamed A. Ashour, Tawab E. Aly and Yousra A. Eldegwee
In such problematic water situation in Egypt, control and saving of the available limited quantity takes great importance from both technical and national points of view. In addition to all the well-known traditional reasons of the problem such as pollution, over usage, and bad traditions of dealing with water, a new very important reason is added nowadays, called “Climate Changes” which has a direct impact on sea water rising, that causes a serious attack of the salt water to the fresh water especially in River Deltas., Not only the surface water, but also the ground water. Since that process proved some acceleration, several investigations have recently considered the worst impacts of climate change and sea water level rise on sea water intrusion. Most of them have revealed the severity of such problem, and the significance of the land movement of the dispersion zone under the sea water level rise situation. In this paper, we try to introduce a technical review and study for the most popular studies concerning our topic, and its most important conclusions, as an approach for preparing the Ph.D. thesis about the Nile Delta water equilibrium in the light of the expected Mediterranean Sea water level rise. Nile Delta, which located between Damietta Branch on the East, and Rosetta Branch on the west, occupies about 20000 square kilometers of the most rich, productive land in Egypt. About 50% of Egyptian population live in that area, agriculture is the main human activities on them, so water is the prime factor in their life, and their agriculture investments. The great amount of this investment depends on the ground water, which faces a serious challenge due to, two reasons, first, is the overuse, and over pumping, while the second is the attack of the salt water due to the Mediterranean Seawater level rise, because of the climate changes. These two reasons must be overcome, if the first reason can be controlled by law, and technical roles, the second reason needs intensive studies and investigations concerning the interaction between seawater and fresh ground water.
Mohamed A. Ashour, Tawab E. Aly and Mahmoud M. Mostafa
The compatibility between the needed structural designed dimensions of the irrigation works and the dimensions of the water stream or the canal in which the irrigation work will be located has a great importance from more than one point of view. As it is well known, the main aim of the designer of such works is to reach the optimum design for maximum performance efficiency with economical cost, and minimize negative technical impacts that may be harmful to the safety of the whole work. Since the complete suitability between the obtained designed dimensions of the different construction elements of the work, and the original properties and dimensions of the canal in which the work will be constructed, is rarely occurring. The designer always has to make some changes in the original engineering properties and dimensions of canals, such as bed width, bed level, and/or inside side slope, to reach the needed suitable compatibility between the structural design and the natural original canal cross section. For the economical purposes, the design always needs less width of the work, than the width of the bed of the original stream cross section, so a contraction may be needed where the work will be constructed; the literature indicated that, such a contraction must not be less than 0.6 of the original bed width. That contraction, of course, has a direct impact on the different hydraulic parameters, such as water depth, velocity, and flow regime in the location of the work. Changes of such hydraulic parameters may exceed their safe permissible values, and so the whole structure may face some dangerous situations, which must be overcome. In this paper, we present a technical survey of the previous research concerning canal width contraction, with the needed technical comments, and comparisons as a logical approach for a master-thesis under the same title.