It is the development of hydroelectric power on a scale serving a small community or industrial plant. The definition of a small hydro project varies, but generating capacity of 1 to 20 megawatts (MW) is generally accepted, which aligns to the concept of distributed generation. Small hydro can be further subdivided into mini hydro, usually defined as 100 to 1,000 kilowatts (kW), and micro hydro which is 5 to 100 kW. Micro hydro is usually the application of hydroelectric power sized for smaller single communities,families or small enterprise. The smallest installations are pico hydro,below 5 kW.Small hydro plants may be connected to conventional electrical distribution networks as a source of low-cost renewable energy. Alternatively, small hydro projects may be built in isolated areas that would be uneconomic to serve from a network, or in areas where there is no national electrical distribution network. Hydro power projects are generally categorized in two segments i.e. small and large hydro. In India, hydro projects up to 25 MW station capacities have been categorized as Small Hydro Power (SHP) projects. While Ministry of  Power ,Government of India is responsible for large hydro projects, the mandate for the subject small hydro power (up to 25 MW) is given to Ministry of New and Renewable Energy. Small hydro power projects are further classified as Class Station Capacity in kW.
Micro Hydro Up to 100
Mini Hydro 101 to 2000
Small Hydro 2001 to 25000