Continuous increase of population in Egypt, limited fresh water, poor maintenance and low efficiency of irrigation systems lead to a real burden on the Egyptian natural water resources. Accordingly, for Egypt, land and water resources management is considered an absolutely strategic priority. In this study, a linear optimization model is developed to maximize the net annual return from the three old regions of Egypt. Data for 28 crops in five years from 2008 to 2012 are being analyzed. The spatial variations of crops, irrigation water needs, crop yields and food requirements are incorporated in the model. The results show that there is a significant reduction in the allocated areas for onion, garlic, barley, flax, fenugreek, chickpeas, lentil and lupine since they are considered as non-strategic crops. On the other side, the allocated areas for strategic crops such as wheat, maize, clover, rice, sugar products and cotton remained almost the same to satisfy their actual food requirements. However, crops with high net returns such as tomatoes have increased substantially. The trend for the gross net benefit is decreasing and is expected to reach a lower value in year 2017. Different approaches and scenarios are analyzed. The developed model proposes a change in the cropping pattern in the old lands of Egypt to increase the gross net return without adding further any other expenses. Keywords: Cropping pattern, Linear programming, Net return, Optimizatio

Breached levees often cause extensive flood damage to urban and residential areas; there has been considerable interest in the numerical modeling of flooding of urban areas in recent years. However, comprehensive data that describe the complex flow field in residential areas are not available for validating the numerical models or for determining the extent of such damage. To fill this gap, results are presented of experiments on a scale model used as a test setup that examined the flow field in an urban area attributable to flooding caused by a levee breach. Steady state flow depths and flow velocity were measured by a point gauge and by an array of ultrasonic velocity profilers, respectively. In addition, the surface velocities were recorded in the entire flooded area by using a digital particle tracking velocimetry technique. The details of these measurements, limited flow data, and the observed flow characteristics are presented in this study. Full data sets are provided on the Internet. The r...

Despite many embankment failures worldwide, data on such failures are limited. An understanding of the embankment failure and the dominant parameters affecting the failure are crucial for predicting and modelling the breach process. Laboratory experiments are conducted on overtopping of embankments consisting of uniform homogenous sand and constructed with different levels of compaction. The temporal changes in the embankment surface profiles and the downstream discharge are measured. Two dimensionless equations are developed for the variation of crest height and embankment bottom length with time as a function of embankment-material dry density. A simple model assuming triangular shape is proposed for the development of breach shape for different compaction levels. Except during the initial stage of the failure, proposed model prediction and the observed data match satisfactorily. The proposed model for the crest height satisfactorily predicts the failure of a laboratory test and three dam failures in SC.

Internal erosion processes due to piping in an earthen levee built in a laboratory flume are reported in this paper. Different sand, silt and clay mixtures are used for constructing the levee. An image processing technique using an edge-detection algorithm is successfully applied to track the erosion process from the recordings of both side and bottom views. The change in the depth of erosion during the piping phenomenon for different soil composition is studied. The results show that small changes in clay content in the soil mixtures significantly affect the erosion rate. The average depth is approximately equal to the average bottom width of erosion in the piping zone. An exponential equation to estimate the depth of erosion as a function of time and the coefficient of soil erodibility is presented. Results for the critical shear stress and the coefficient of soil erodibility agree well with those obtained from the hole erosion test but not with those obtained from the jet erosion test.

This paper presents experimental results on partial-breach dam-break flows. Three-dimensional (3D) flood waves resulting from an instantaneous breach of a dam are experimentally investigated by combining different measurement techniques. The dam-break flow is initiated by quickly lifting a gate separating a reservoir and a downstream dry basin. Three different initial upstream water depths are considered. The study utilizes the digital particle tracking velocimetry (DPTV) technique for measuring the free-surface velocity and water depth. Stereoscopic configuration of two high definition video cameras recording the movement of hollow plastic balls enabled measurement of the 3D velocity field and the water-surface elevation in the near field. The pressure head is measured by pressure transducers at various locations. Ultrasonic velocity profilers (UVP) are used to obtain velocity profiles in the emptying reservoir. A simple nondimensional relationship for the variation of water-surface elevation in ...