Distribution Reservoirs

Distribution reservoirs also called service reservoirs are the storage reservoirs, which store the treated water for supplying water during emergencies (such as during fires, repairs, etc.) and also to help in absorbing the hourly fluctuations in the normal water demand.

Function of distribution reservoirs

• To absorb the hourly variations in demand.
• To maintain constant pressure in the distribution main.
• Water stored can be supplied during emergencies.

Location & height of distribution reservoirs

• Should be located as close as possible to the centre of demand.
• Water level in the reservoir must be at sufficient elevation to permit gravity flow at an adequate pressure.

Types of reservoirs

Depending upon the elevation with respect to ground, may be classified into-

• Surface reservoirs
• Elevated reservoirs

Surface reservoirs

• These also called ground reservoir.
• Mostly circular or rectangular tanks.
• Underground reservoirs are constructed high natural grounds and are usually made of stones, brick, plain or reinforced concrete cement.
• The side walls are designed to take up the pressure of the water, when the reservoir is full and the earth pressure, when it is empty.

Elevated reservoir

• It is also referred to as overhead tanks are required at distribution areas which are not governed and controlled by the gravity system of distribution.
• These are rectangular, circular or elliptical in shape.
• If the topography of the town not suitable for under gravity, the elevated tank or reservoir are used.
• They are constructed where combine gravity and pumping system of water distribution is adopted.
• These tanks may be Steel or RCC.

Types of tanks

• R.C.C. Tanks
• G.I. Tanks
• H.D.P.E. Tanks

R.C.C. Tanks

• It is of reinforced concrete cement.
• They have long life.
• Very little maintenance.
• Decent appearance.

G.I. Tanks

• It is if galvanized iron.
• Generally square or rectangular in shape.
• Life of tank is hort.
• Corrosion of metal occurs.
• Maintenance cost is high.

H.D.P.E. (High Density Polyethylene) Tank

• It is very popular for storing less quantity of water and hence useful for residential purpose.
• Handling is easy because of light weight.
• Cheap in cost.
• Maintenance cost is low.
• Cleaning of tanks is easy.