This project was one of the last to be started with funding from 2004 Indian Ocean Tsunami and should have been completed last year, but was held up as the crucial part of any pipeline, is a surge vessel, pictured above. This had to be made in India and transported by sea to Sri lanka which delayed the project
So some of you may be asking, what is a surge vessel ?
A surge tank (or surge vessel) is a standpipe or storage reservoir at the downstream end of a closed aqueduct or feeder pipe to absorb sudden rises of pressure as well as to quickly provide extra water during a brief drop in pressure. An open tank to which the top of a surge pipe is connected so as to avoid loss of water during a pressure surge.
Consider a pipe containing a flowing fluid. When a valve is either fully or partially closed at some point downstream, the fluid will continue to flow at the original velocity. In order to counteract the momentum of the fluid the pressure will rise significantly (pressure surge) just upstream of the control valve and may result in damage to the pipe system. If a surge chamber is connected to the pipeline just upstream of the valve, on valve closure the fluid instead of being stopped suddenly by the valve will flow upwards into the chamber hence reducing the surge pressures experienced in the pipeline.
Upon closure of the valve, the fluid continues to flow, passing into the surge tank causing the water level in the tank to rise. The level in the tank will continue to rise until the additional head due to the height of fluid in the tank balances the surge pressure in the pipeline. At this point the flow in the tank and pipeline will reverse causing the level in the tank to drop. This oscillation in tank height and flow will continue for some time but its magnitude will dissipate slowly due to the effects of friction.