To equalize the variation in hourly demand of water by the consumers to a uniform rate of supply from the source either by gravity or pumping.
To maintain the desired minimum residual pressure in the distribution system.
To provide the required time for the disinfectant added in order to achieve effective disinfection. And
To facilitate carrying out repairs either to the pumping or to pump-set without interruption to the supply of water.
Components &Its Functions Inlet pipe for the entry of water. Outlet pipe connected to the distribution mains for the exit of water. Overflow pipe discharging into drain gutters and maintaining constant level. A float gauge or an indicator for indicating the depth of water which can be read from out side. a wash-out pipe for removing water after cleaning the resrvoir. Automatic devices to stop pumping when the tank is full.
Ladders to reach the top of the reservoir and then upto the bottom of the reservoir for inspection. Manholes for providing entry into the tank for inspection purpose. Ventilator for freh air circulation
Surface Reservoirs Surface reservoirs are circular or rectangular tanks constructed at ground level or below gronund level. Therefore they also called as ground reservoirs. They are generally constructed at high points in the city. In a gravitational type of distributional system. And pumping system used for treated water is filled the reservoir s.
These tanks may be made of R.C.C, steel, or prestressed concrete.
Stand Pipes Stand pipes are a kind of elevated tanks without any erected towers for resting the body. They are thus tall cylindrical shells resting directly on the ground.
Storage Capacity The total storage capacity of a distribution reservoir is the summation of : Balancing storage (equalizing/operating storage) Break-down storage And Fire storage Balancing storage : The main and primary function of the distribution reservoir is to meet the fluctuating demand with a constant rate of supply from the treatment plant.The quantity of water required to be stored in the reservoir for equalizing or balancing this variable demand against the constant supply.
Break-down storage : It also called as emergency storage. It is the storage preserved in order to tide over the emergencies posed by the failure of pumps, electricity, or any other mechanism drinving the pump. Fire storage : The third component of the total reservoir storage. In case of fires sufficient amount of water must remain available in thereservoir for throwing it over the fire.