NOVELTY - Feedline is interconnected to inlet pipe(s) (220) perpendicular to flow of water, and turbine generator combination (240). Turbine generator combination is interconnected with pressure dissipation device (250). Outlet pipe(s) (260) is interconnected with pressure dissipation device. Water is made to flow through inlet pipe(s), feedline, turbine generator combination, pressure dissipation device and outlet pipe(s) such that water is released back into stream or river. Electricity is generated from the flow of water passing through the turbine generator combination.    USE - For generating hydroelectric power.    ADVANTAGE - The method enables efficient generation of hydroelectric power with suppressed environmental pollution, and enables safe release of water into stream or river.    DETAILED DESCRIPTION - Feedline is interconnected to inlet pipe(s) (220) perpendicular to a flow of water in a stream or river, and turbine generator combination (240) which outputs electrical power. The inlet pipe(s) have a length and apertures along longitudinal direction. The turbine generator combination is interconnected with a pressure dissipation device which reduces pressure of water. Outlet pipe(s) is interconnected with pressure dissipation device. The outlet pipe(s) have an elevation lower than the inlet pipe. Water is made to flow through inlet pipe(s), feedline, turbine generator combination, pressure dissipation device and outlet pipe(s) such that water is released back into stream or river without having negative effect on oxygen level in water. Electricity is generated from the flow of water passing through the turbine generator combination. An INDEPENDENT CLAIM is included for hydroelectric power generating apparatus (200).    DESCRIPTION OF DRAWING(S) - The figure shows the top view of the hydroelectric power generating apparatus.    Hydroelectric power generating apparatus (200)    Inlet pipe (220)    Flow control valve (234)    Turbine generator combination (240)    Pressure dissipation device (250)    outlet pipe (260)