DAMS CONSTRUCTION AND SIDE SELECTION

DAMS

. A dam may be defined as a solid barrier constructed at suitable location Across river valley with a view of impounding water flowing through That River.

                                                     OR

. Dams  are hydraulic structure built across rivers and stream to confine water

On upstream side and utilize this flow of water for multipurpose.

Dams are created for the following  objectives  Or  Purpose

• Generation of hydropower energy.
• Providing water for irrigation facilities.
• Fish farming.
• Fighting droughts.
• Controlling of floods.
• Water supply for domestic consumption.
• Providing navigational facilities.

DIFFRENT PARTS AND TERMINOLOGIES OF DAMS

Crest:

The top of the dam. These may be in some cases be used for providing a roadway or walkway over the dam.

Parapet walls:

low protective walls on either side of the roadway or walkway on the crest.

Spillway:

A spillway is a section of a dam designed to pass water form the upstream side of a  dam      to the downstream side.

Many spillways have floodgates designed to control the flow through the spillway

Free Board:

This is the free board can be defined as the distance   between the mix water level normal water level of the dam this distance between the maximum and normal water level it is called free board.

Gallery:

A gallery is the small tunnel like way for the different purposes it may be provided and the longitudinal        direction are in the transverse direction provided for storage of the equipment used to determine the performance of the building or the small spaces room provided for the people to live . The dam specification inside this room . A passage tunnel provided inside the dam .

Sluice way:

A provided to clear the silt accumulation in the reservoir .

Heel:

Portion   of the dam in contact with ground or river- bed at upstream side.

Toe:

portion of the dam in contact with ground or river-bed downstream side.

Types of Dams

Classification of dams can be two types.

• Based on function .
• Based on structure and design .

BASED ON FUNCTION:

.Storage dam. 

                     It is a structure

 The major purpose of this structure is to store water.

.Diversion dam.

The major purpose f a diversion is to divert the water form its natural

 course.

Detention dam.

In detention dam this also serves the purpose of a storage dam but this detention dam prevents the floods at a entering into downstream area this detention dam retains water in releases it gradually to the downstream down this prevents a floods to flood prone areas.

Debris dam.

This dam prevents all the debris like silt and sand , locks of wood leaves entering into the downstream side.

Coffer dam.

 Coffer dam is temporary structure which major purpose it restricts the water entering into the construction site well construction process is going so this is temporary structure.

BASED ON STRUCTYE AND DESIGN:

Gravity dam.

The gravity dam is the massive concrete or Rockville structure with the weight of the dam itself restricts the horizontal thrust of the water. The gravity dam have strong foundation

Arch dam.

In this arch dam we have it is curved in plan.it has a convexity on the upstream side This diverts the horizontal thrust to the strong abutments.

Buttress dam.

This dam has a long concrete reinforced concrete slab which is supported by these buttresses this structure totally restricts the horizontal thrust of the water.

Embankment dam.

The section of this dam looks like an embankment it looks like an hill where you have an impervious core. Coming to its strength this don`t have concrete and asphalt as its major ingredients.

SELECTION OF DAM SITE.

• Suitable foundation must be available.
• For economy, the length of the dam should be as small as possible, and for a given height, it should store the maximum volume of water.
• The general bed level at dam site should preferably be higher than that of the river basin. This will reduce the height of the dam.
• A suitable site for spillway should be available in the near vicinity.
• Materials required for the construction of dam should be easily available, either locally or in the near vicinity.
• The value of land and property submerged by the proposed dam should be as low as possible.
• The dam site should be easily accessible, so that it can be economically connected to important towns and cities.
• Site for establishing labor colonies and a healthy environment should be available near the site.