Question

how to make a hydroelectric power plant   its very urgent

Answer 1

A model of hyderoelctric power plant for this-
You will need a water reservoir, some form of turbine, and something connected to the turbine to represent a generator. 

The water reservoir can be just about anything that can contain water at an elevation above that of your turbine. In the real world, this is usually a dam, so you may want to model something that looks like a dam. 

Water from the elevated source is allowed to flow from the source past a water turbine. You could make a waterfall and paddlewheel so that people can see the workings, but in an actual generation station, this is a pipe and the turbine is enclosed. 

The turbine turns as a result of the water flow. A generator is connected to the shaft of the turbine. You can use a permanent magnet motor for your generator. Just hook up a voltmeter to what would normally be the battery leads of the motor to show the voltage being generated. Chances are, your model won't be able to generate enough power to light a bulb, so showing the voltage with a voltmeter is a simple way of demonstrating the principle. 

A: We need these things to make a hydroelectric power station: 
1.cardboard 
2.aluminium foil or butter paper 
3.chart paper 
4.a generator 
5.a turbine made of plastic 
6.a 1.5 volt battery