Recently, because people are taking a great interest in the water supply system and the related facilities are getting larger, the surge suppression is very important problem. The waterhammer occurs when the pumps are started or stoped for operation or tripped due to the power failure. As the waterhammer problems as a result of the pump power failure were very serious, these situations were carefully investigated. Accordingly, we carried out both numerical simulations to confirm the safety fot the intergrated operating of 1st stage and 2nd stage Juam intake pumping station in which had the in-line pumps. In this paper, it was reviewed that the water supply system has the reliability on the pressure surge, in case the air chambers were installed at both the inlet and the oulet of the in-line pumping station. we are sure that Juam intake pumping station in which have the air chambers is safe for the waterhammer.

This study suggested an improvement of existing tunnel drainage system to prevent pavement crack, floating, rising due to tunnel seepage water at the time of heavy rains. First, we derive the main cause through case studies of poor drainage, such as pavement damage due to tunnel seepage water at the time of heavy rains, poor drainage in the changing sections of superelevation, and pipe clogging due to calcification. On this basis, we suggested four drainage improvement systems depending on the range of watering and its urgency, as follows: Drain hole drilling and installation of induced ditch, Pipe installation connected to collecting well, Installation of block out on the side of collecting well and filter layer, Installation of holes for maintaining dummy ditch. In conclusion, through such improvements suggested above, we expect that we will be able to effectively prevent pavement damage due to tunnel seepage water. Consequentially, it will also contribute improving the safety of vehicles in the expressway.

Recently, because pepople are taking a great interest in the water supply system and the related facilities are getting larger, the surge suppression is very important problem. Accordingly, We carried out both numerical simulation and field tests to confirm the safety of intake pumping station.