Energy resources are grouped into three categories:fossil fuels,
renewable resources and nuclear resources.
Renewable energy resources can be used to produce energy again and again,e.g.
hydropower,solar energy,wind energy,biomass energy,geothermal energy,etc. [1].
Hydropower currently represents worldwide a significant source of electrical energy and compared to fossil and nuclear fuel,hydro resources are widely distributed [2].
It contributes to one-fifth of the total power worldwide and in many countries it is the only domestic source for electricity generation [3].
The 1997 report on survey by the International Journal on Hydropower and Dams indicated that at least 50% and 90% of the national electricity in 63 and 23 countries respectively are sourced from hydro [2].
The role hydro resource is playing in generating electricity is substantially greater than that of any other renewable energy technology and vast potential still remains in under developed countries [3].
Hydropower project exists in a wide range of scale as well as types and the design is made to suit the needs and conditions at a particular site [3].
Small, mini and micro-hydro plants play a key role of rural electrification in
many countries [2,5] and they have greater capacity than all other renewable energy sources to make instant impact on the replacement of fossil fuels.