The 412 MW Romper Hydro Electric Project is downstream extension of Nada Khaki Hydro Electric Project and is located in Simla and Lulu district of Hi michal Prudes. The Romper Intake Structure is already constructed as part of tail race outfall structure of Nada Hake Hydro Power Station (1500 MW). At RD of 484m the HURT crosses under river Sale from Left Bank to right bank. In order to execute the river crossing of REP, a diversion tunnel 10.0m Thia Horse Shoe was constructed on left bank of river along with U/S and D/S Coffer Dams. Earlier it was planned that the river crossing portion of the HURT would be constructed as cut & cover section from the river side because the crown of HURT was close to the river bed rock. Since this work had to be completed during short low flow period in one working season, the planning was changed during advanced construction stage. The HURT was re-graded so that it could be tunneled and lined under bed rock without day lighting. At the same time, the work of exposing the bed rock for providing per support to rock above tunnel, laying the protective raft and strengthening of rock abutments of both sides of river was done from the surface. In the river crossing area in a length of 93.2 m RC structure has been provided with lining thickness of about 1.5 m capable of resisting extreme loading condition of internal pressure when the tunnel is flowing full and the external load for case when HURT is empty and the river is in high flood. Additionally a protective RC raft and protection with large boulders set in rich concrete have been provided from the river side. This strategy of simultaneously attacking from two fronts i.e. one under the river bed from construction edit cum Spill tunnel and the other from river side by constructing a temporary access to the top portion of river crossing paid rich dividend by successfully completing the river crossing in one lean flow season. This paper describes the design approach taking into consideration various loading conditions and the construction methodology adopted.


Romper Hydro Electric project (412MW), located in the Northern Power Region, is a downstream extension of Nada Khaki Hydroelectric project utilizing 383.88 comics of design discharge available at tail race outfall of HEP. This project is economically attractive as discharge of HEP outfall is diverted through the Intake structure already constructed for this purpose thus saving the cost of independent desalting and major diversion arrangement. The HEP is located on the left bank of river Sale at Khaki. The water further enter into 3 underground pressure shafts, surface valve house & after that it is conveyed through surface pen stocks of 5.4m Thia each bifurcating into six 3.8m Thia to feed the six generating units in Surface Powerhouse equipped with Francis turbines each generating capacity of 68.67 MW.

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