In this paper the effect of vortex formation upstream inclined sluice gate, discharge coefficient as well as predicted discharge equation have been studied for several gate openings (3,4&4.5) cm, five discharges and three different gate cases, vertical and inclined opposite flow direction in (30 and 45)° angles. It was found that there is no vortex at vertical sluice gate but observed at gate inclined opposite flow direction. There are tow corner vortices in high discharges and one central vortex in low discharges. The reduction of these vortices has been studied by vortex decay elements. The average discharge coefficient for vertical gate was 0.645 while these values reduced to 0.59 and 0.564 for gate inclined (30 and 45)° opposite flow direction respectively

The work concerns a laboratory study to investigate the effect of changing the bed roughness of the main channel on the branching discharge and separation zone formed in the main channel as a result of discharging flow through a branch channel.The ratio ofmain channel roughness to the roughness of the branch channel bed has been changed between (1.7 – 3.9) for two branching angles (30˚ , 90˚ ) and for different values of main channel discharge ranged between (7 – 17) L/sec. Laboratory result shows that branching discharge ratio increases by the increasing the total discharge through the main channel at roughness ratio less than (2), where's the branching discharge decreases at roughness ratio greater than (2), and stay constant at roughness ratio about (2) for all discharge passing through the main channel.The result shows that the length of the separation zone decrease with the increasing in the roughness ratio and total discharge through the main channel.

This paper present the effect of the lower gate lip on the coefficient of contraction, velocity and discharge which have been made in a rectangular flume with four gates opening from (2 to 4.5) cm, five different discharges from (6.2 to 18.15) l/s and five different gate cases (vertical and inclined vertically) by angle (45)° with and opposite flow direction with horizontal and sharp lower lip. The values of coefficients of contraction (Cc) and discharge (Cd) increases when gate slope increases with flow direction and the lower lip is horizontal, these increases are (16)% and (18)% respecttively, while these values decreases when gate slope increases opposite flow direction and the lower lip is horizontal these decreases are (13)% and (11)% respectively. The values of coefficient of velocity (Cv) remain constant and don’t effect with changes of gate slope or gate lip.

In this paper the effect of the lower gate edge on the water surface profile (W.S.P) have been studied in a rectangular flume with four gate openings (2, 3, 4 and 4.5) cm, five upstream of water heads (18.9,21,24,26 and 28.9) cm and five gate cases (vertical and inclined vertically by angle (45) o with and opposite to flow direction )with horizontal and sharp lower edge ( inclined by angle (45) o ) Were adopted in the experiments. The results show that the convergence length for inclined gate with flow direction and horizontal edge increases by (28.7)% with respect to vertical, while decreases by (21.4)% when gate inclined opposite to flow direction and horizontal edge. The convergence angle decreases by (38.7)% when gate inclined with flow direction and horizontal edge, while increase by (22.4)% when gate inclined opposite flow direction and horizontal edge. The horizontal lip for the inclined gate with flow direction reduced the (W.S.P) convergence angle and then reduced the scour downstream sluice gate.

This paper present the variation between brink and critical depths for free overfall, of water over two models of broad crested weirs with different edge, straight vertical and skewed with an angle (30)o. The discharge was measured for the two models and compared with calculated one observed from theoretical equation. The results showed that the calculated discharge is greater than the measured one by (3.5&14.5)% for straight vertical and skew models respectively, and the skew model discharge is greater than that for the straight vertical by (13%). Also, the results indicated that the coefficient of discharge for skew model is less than that for the straight vertical one by (8%). Meanwhile for the same discharges the brink depth for straight vertical model is greater than that for skew model by (11%). The study also showed that the distance upstream the weir (x), at which the critical depth intersected with water surface profile, for skew model is greater than the straight vertical model by (63%).