Flow and scour characteristics are investigated experimentally on a modified roughened bed. The water su is recorded at different sections. The paper investigated the effects of using curved steel sheets as roughne for strip and staggered arrangement, on different flow and scour characteristics. It was found that the apro staggered roughness length increases the relative energy loss by 17%, reduces the relative jump length by decreases the relative jump depth by15.5% compared to the smooth bed. Generally, the experiments indic case of staggered roughness elements gives the best relative jump characteristics. Moreover, it plays an im to control the scour downstream the basin. The derived theoretical equations for relative depth and the rel loss give an acceptable agreement with the experimental data. Prediction equations were developed using linear regression (MLR) to model the hydraulic jump characteristics. A good agreement was obtained betw predicted and the measured values. Finally, this study yielded conclusions which can be recommended in t procedure and practical applications

This paper presents experiments and computer simulation for the erosion and deposition processes along a 180° open canal bend. The computer simulation is conducted by Nays2DH model in iRIC software. The models are conducted with the curvature's radius ratio (Ø/L) varies within 3.0 to 8.5. Experiments produced that the erosion and deposition actions decrease as Ø/L increases. The minimal erosion and deposition are detected at (Ø/L =8.5). The optimum place of a bridge circular support along the bend is defined. The results of Nays2DH Model are compared with tests. RSQ for the modelled statuses is 88.329% and the correlation factor between simulations and the gauged depths is 93.98%.

Whenever a cleaning process and removal of weeds from water channels is carried out, the weeds re-appear in a matter of weeks and sometimes days. This costs a lot of effort and money. Hence, there is an urgent need for harmonization between the presence of weeds of acceptable densities and to maintain water levels in the last reaches of the channels which are mainly infested by the weeds. The present paper aims to study experimentally the impact of the existence of submerged weeds on the flow characteristics in case of maintaining the water levels behind the infested areas. The data were collected using a laboratory flume of relatively large dimensions (60cm wide, 65 cm depth, and 20.8 m long) with fixed bed slope (0.0062). Flexible branched roughness elements were used with different intensities (0.0062, 0.0123, and 0.0246). The weeds intensities were tested with different discharges and different tail water depths. Dimensional analysis was used to correlate the flow characteristics to the other relevant parameters of the flow and weeds. Dimensionless general equations in terms of these parameters for computing both heading up, relative energy loss, Manning coefficient and relative shear velocity of the flow through the infested reach were developed and compared with the experimental data. The comparison proved a good reliability and high accuracy. The equation of Manning coefficient was reduced to the case of non-infested canals and verified with different irrigation canals (El-salam main canal and its branches Om El-Reesh , San El-hagar stage 2 and 3 and El-Sheikh Gaber canal).

Local scour due to free hydraulic jump downstream hydraulic structures may cause damage or complete failure of these structures, so controlling of this phenomenon is very important. The main goal of this study is to reduce the characteristics of a scour hole downstream sudden expansion stilling basin. An experimental study was conducted to study the effect of expansion ratio and position of the sill. Ninety experimental runs were carried out considering the wide range of Froude numbers ranging from 3.42 to 8.67. Five values of the expansion ratio (e = 2.73, 1.92, 1.76, 1.50 and 1.25) and four values of the relative position of lateral single sill (Lx/LB = 0.20, 0.30, 0.40 and 0.50) were investigated. The dimensional analysis was employed to drive expressions correlating the different variables affecting the scour phenomena. It was found that, the flow patterns in most of the cases were a symmetrical and the resulting scour and deposition were also a symmetrical. The relative scour depth, the relative scour length and the relative energy loss, increase by increasing the initial Froude number and vice versa. The expansion ratio (e = 1.50) gives the minimum values of scour dimensions. The best location of the sill for reducing the scour dimensions at 0.30LB from the gate opening. Prediction equations were developed using the multiple linear regression (MLR) to model the relative scour depth Ds/y1 and the relative scour length Ls/y1.

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