Application of VES and TDEM techniques to investigate sea water intrusion in Sidi Abdel Rahman area, northwestern coast of Egypt

The present study is an approach to detect the sea/freshwater interface in Sidi Abdel Rahman area, northwestern coast of Egypt using both vertical electrical sounding and time domain electromagnetic. The measured vertical electrical soundings are interpreted in 1D and 2D manner. The 1D inversion is carried out using the commercial software (RESIST), whereas 2D resistivity nonlinear iterative inversion scheme based on the finite element technique and regularization method was used. The time domain electromagnetic stations are interpreted using Temixxl-4 software by Interpex Ltd. To have the advantages of the vertical electrical sounding in shallow depths and time domain electromagnetic in deep depths, a joint inversion algorithm is applied for the electric profile and the nearby electromagnetic profile. Very low resistivity values have been observed near the coast as well as a considerable salt/fresh water interface. The tip-top portion of the interface lies approximately 1,000 m from the shore line.     

SCOUR HOLE CHARACTERISTICS BELOW FREE OVERFALL SPILLWAY

1 INTRODUCTION Flow through hydraulic structures often issues in the form of jets. The jet velocities are usually high enough to produce sizable, even dangerous scour hole. The extent of the resulting scour depends on the nature of bed material and flow characteristics. The erosion process is quite complex and depends upon the interaction of hydraulic and morphological factors. Scouring may lead to: endangering the stability of the structure by structural failure or increased seepage, end…     

Geostatistics of near-surface moisture in bare cultivated organic soils

The aim of this study was to characterise fine scale patterns of organic soil moisture content in the top 5 cm by means of semi-variogram modelling. Soil moisture content was observed along a transect on 2 occasions, early in the 1999 growing season to avoid any influences originating from vegetation and cultural practices. Soil moisture values were found to be normally distributed and were not significantly correlated with the soil organic matter content. Many similarities were depicted between the exponential semi-variograms characteristics of this study and another one in mineral soils, reported in the literature, except for the much higher sills associated with organic soils. Of particular interest were similar correlation lengths, indicating that a correlation range of the order of 100 m should be expected for mineral soils and for the level of moisture and organic matter contents found in this study.     

Experimental study on scour and flow field in a scour hole around a T-shape spur dike in a 90° bend

In this paper results of experimental study on scour and flow field around a T-shape spur dike in a 90 degree channel bend are presented. Experiments were conducted in a laboratory channel to measure the variations of bed topography under a clear water condition. The three dimensional flow field was measured by an Acoustic Doppler Velocimeter in a scour hole due to a T-shape spur dike. It was found that by increasing the Froude number and length of spur dike the amount of scour increases. Increasing the wing length of spur dike decreases the scour. The amount of scour at the upstream of spur dike is much more as compare to that at the downstream of spur dike. By increasing the wing length of spur dike the zone of flow separation expands. As a result the sizes of vortex increase. Details of flow field are also addressed in the paper.     

Stochastic analyses of maximum daily rainfall series recorded at two stations across the Mediterranean Sea

Independence, stationarity, homogeneity, trend, and periodicity tests are applied on 48-year-long complete and 79-year-long incomplete maximum daily rainfall series recorded at Alexandria, Egypt, and on 61-year-long maximum daily rainfall series recorded at Antalya, Turkey, which are located at the southeastern and northeastern shores of the Mediterranean Sea. The results indicate no significant trend and no periodicity in mean, and both series are independent and homogeneous. Linear regression trend test applied to the 10 % highest part of the Alexandria series indicated a significant increasing trend. Next, frequency analysis is applied on each of these series by the probability distributions of Gumbel, general extreme-values, three-parameter log-normal, Pearson-3, log-Pearson-3, log-logistic, generalized Pareto, and Wakeby. The distributions, except for the generalized Pareto and Wakeby, pass the χ ² and Kolmogorov–Smirnov goodness-of-fit tests at 90 % probability. By visual inspection of the plots of histograms together with the probability density functions, and by the results of the χ ², Kolmogorov–Smirnov, and probability plot correlation coefficient tests, the general extreme-value distribution whose parameters are computed by the method of probability-weighted moments is deemed to be suitable for these two maximum daily rainfall series.     

Application of soft computing in predicting rock fragmentation to reduce environmental blasting side effects

In the blasting operation, risk of facing with undesirable environmental phenomena such as ground vibration, air blast, and flyrock is very high. Blasting pattern should properly be designed to achieve better fragmentation to guarantee the successfulness of the process. A good fragmentation means that the explosive energy has been applied in a right direction. However, many studies indicate that only 20–30 % of the available energy is actually utilized for rock fragmentation. Involvement of various effective parameters has made the problem complicated, advocating application of new approaches such as artificial intelligence-based techniques. In this paper, artificial neural network (ANN) method is used to predict rock fragmentation in the blasting operation of the Sungun copper mine, Iran. The predictive model is developed using eight and three input and output parameters, respectively. Trying various types of the networks, it was found that a trained model with back-propagation algorithm having architecture 8-15-8-3 is the optimum network. Also, performance comparison of the ANN modeling with that of the statistical method was confirmed robustness of the neural networks to predict rock fragmentation in the blasting operation. Finally, sensitivity analysis showed that the most influential parameters on fragmentation are powder factor, burden, and bench height.     

Spatio‐temporal evaluation of the groundwater quality in Kafr Al‐Zayat District,Egypt

Eighteen groundwater well sites located in Kafr Al‐Zayat (Egypt) were sampled monthly from January 2009 to November 2011 for microbial content, Mn⁺², Fe⁺², total dissolved solids (TDS), total hardness, NO₃^?, and turbidity. The data were analyzed combining the integrated use of factor and cluster analyses as well as the geostatistical semi‐variogram modeling. The prime objectives were to assess the groundwater suitability for drinking, to document the factors governing the spatio‐tempral variability, and to recognize distinctive groundwater quality patterns to help enable effective sustainability and proactive management of the limited resource. The groundwater microbial, Mn⁺², Fe⁺², TDS, and total hardness contents violated the drinking water local standards while the turbidity and the nitrate content complied with them. Factor analysis indicated that the microbial content is the most influential factor raising the variability potential followed, in decreasing order, by Mn²⁺, Fe²⁺, TDS, NO₃^?, turbidity, and finally the total hardness. Turbidity resulting from urban and agricultural runoff was strongly associated with most of the quality parameters. Quality parameters fluctuate sporadically without concrete pattern in space and time while their variability scores peak in November every year. Three spatially distinctive quality patterns were recognized that were consistent with and affected by the cumulative effects of the local topography, depth to water table, thickness of the silty clay (cap layer), surface water, and groundwater flow direction and hence the recharge from contaminated surface canals and agricultural drains. Copyright © 2013 John Wiley & Sons, Ltd.     

Seismic design of yielding structures on flexible foundations

This paper introduces a simple method to consider the effects of inertial soil–structure interaction (SSI) on the seismic demands of a yielding single‐degree‐of‐freedom structure. This involves idealizing the yielding soil–structure system as an effective substitute oscillator having a modified period, damping ratio, and ductility. A parametric study is conducted to obtain the ratio between the displacement ductility demand of a flexible‐base system and that of the corresponding fixed‐base system. It is shown that while additional foundation damping can reduce the overall response, the effects of SSI may also increase the ductility demand of some structures, mostly being ductile and having large structural aspect ratio, up to 15%. Finally, a design procedure is provided for incorporation of the SSI effects on structural response. Copyright © 2015 John Wiley & Sons, Ltd.     

Thresholds of land cover to control runoff and soil loss

This research focused on the determination of land cover thresholds that have a significant impact on runoff generation and soil loss at the pedon scale. For this purpose, six erosion micro-plots were set up on grassland and shrubland types of rangeland in the northeast of Iran, and the amounts of vegetation cover, litter, runoff and soil loss on them were measured. A factorial statistical analysis was carried out on the completely randomized design using land cover and rainfall factors. The results show that the effect of rainfall on soil loss and runoff was greater than that of land cover. Also, the effect of land cover on soil loss was greater than that on runoff generation. Furthermore, two specific thresholds were identified: the first was from 10 to 30% of landcover and the second from 50 to 70%.