The trash rack is generally provided as a cover for entrance to intakes and dam outlets so as to prevent entry of debris, ice, etc into conduit. These are bar screens made from steel bars spaced at 5 to 15 cm center to center in both directions.

The discharge through outlet is given by ?
Q = C_d. A. (2gH_L)^1/2 where H_L = 226 ? 210 = 16 m
Q = 0.8 x (?/4 x 16) x (2 x 9.81 x 16) = 164 cumecs.

Steel is strong in tension and even large size diameter pipes can be made of thin shells. They are refore lighter than cast iron pipes. Welded pipes are smoor and stronger than riveted pipes. But steel pipes get rusted easily and are protected on inside as well as outside by protective coatings.

The structure may vary from a simple concrete block supporting end of conduit pipe to huge concrete towers. It is constructed at entrance of conduit. The basic function is to help in safely withdrawing water from reservoir over a predetermined range of pool levels.

When a liquid is flowing in a pipeline is abruptly stopped by closing of valve, it destroys momentum and retards velocity of water column behind. This exerts a thrust on valve, an additional pressure on pipe shell and it may be so high as to cause bursting of pipe shell. The more rapid is closure of valve, more rapid is change in momentum and hence, greater hammer pressure is developed.

The discharge passing through dam outlet is given by using equation-
Q = C_d. A. (2gH_L)^1/2 where C_d is coefficient of discharge = 0.62 for free over-fall, H = Water head over centre line of sluice = 330 ? 300 = 30 m and A = ?/4 x 4 = 3.14 m²
Q = 0.62 x 3.14 x (2 x 9.81 x 30)^1/2 = 47.23 cumecs.

Penstocks are huge diameter pipe which carries water under pressure and structural design is similar to that of pressure pipes. Since re is a possibility of sudden load changes in penstocks which changes pressure and flow velocity which characterizes turbulent flow in fluid dynamics.

Douma has suggested following equation ?
i. For circular conduits: 4X² + 44.4 Y² = d² where d is diameter of circular conduit
ii. For rectangular tunnels or conduits: X² + 10.4 Y² = d² where d is width or height of conduit depending on wher sides or top and bottom curves are being designed. Where X and Y are coordinates of any point on curve and d is width or height of conduit.

Galvanised steel pipes (with circumferential corrugations) are much stronger than ordinary steel pipes. These are usually manufactured in various sizes varying from 20 cm to 2 meters in diameter. They are lighter and can be more easily transported at distances and are widely used where large pipes of smaller wall thickness are required.

The head loss (H_L) by pipe friction is given by Darcy-Weisbach equation ?
H_L = f?. V². L / 2gd where L is length of pipe in meters, d is diameter of pipe, V is velocity of pipe and f? is friction factor which depends on Reynold?s number and relative roughness of pipe.
It is clear from given equation that head loss is directly proportional to length of pipe hence head loss increases with increase in length of pipe.