The value of K and n depends on upstream slope. For vertical u/s face of spillway, K is 2.0 and n is 1.85 and for slope 1H : 3V, K = 1.936 and n = 1.836. For slope 1H : 1 1/2V, K = 1.939 and n = 1.810.

A flared inlet called morning glory is often used in large projects. The horizontal tunnel is eir taken through dam body or below foundations. Chute blocks, dentated sills and baffle piers are all auxiliary devices which help in energy dissipation.

Straight drop spillway is a low weir and simple vertical fall type structure which may be constructed on thin arch dams or small bunds etc. An ogee spillway is most suitable for concrete gravity dams. Chute spillway can be provided easily on earth and rock-fill dams.

When Froude number is in range of 2.5 to 4.5, jump is troublesome and oscillating. This gives rise to heavy waves on surface and wave suppressors are needed in this range.

The extra concrete is required for thickening of section at d/s end which can be saved by shifting curve of nappe in a backward direction until it becomes tangential to d/s face. It can be affected by providing a corbel on u/s face.

In dropping shutters, shutters are hinged at bottom and are supported by struts and se shutters can be raised or lowered from an overhead cableway or a bridge. They work on principle of counterweights against water pressure.

The radial gates consists of steel plates with struts which are pinned at center of circular plate. When water level rises above FRL gates are raised by hoisting arrangement to allow flood water to discharge freely. Each gate is separately housed between two piers constructed on crest.

A shaft spillway is generally adopted when possibility of an overflow spillway and a trough spillway has been ruled out. The discharge does not increase at such a high rate as in weir type spills. Hence, it may not prove as useful as a weir type spills if unestimated high floods occur.

Most of kinetic energy is destroyed by creating a condition suitable for formation of a hydraulic jump. Sometimes depth of tail-water may be more than that necessary to create hydraulic jump. The depth of water can be reduced to create a hydraulic jump by providing a sloping apron.

It is an improvement over free over-fall spillway. It is mostly suitable for concrete gravity dams especially when spillway is located within body of dam in same valley.