The civil wroks of micro hydropower station-The function of Spillway
The Spillway (overflow weir) usually used In front of the inlet, channel (long), forebay.
The main function of the spillway or overflow weir is to discharge the excess water from the channels to the downstream micro hydropower station or other appropriate places. When the load decrease of your micro hydropower station, the required water flow as also reduce for your micro hydro turbine generator, but the water flow from inlet channel is still flowing, and therefore, resulting in the water volume of the forebey gradually increased, water level rising gradually, so finally the excess water will spill from the top of the forebay pool and cause accident.
The arrangement place of the spillway (Overflow dam) in the forebay pool can be side weir or from weir. But generally the side weir is a better choice, because this position can reduce the front dam width of the forebay pool. Of course actual design should consider the local terrain conditions to determine the appropriate arrangement.
The water flow of micro hydropower station generally is not too big, micro hydropower station owner can choose spillway (overflow weir) without sluice gate. The structure,of this weir is simple and easy to manage. The water level rises in the pool are automatically overflowed; you don’t need to worry too much.
The size of the spillway (overflow weir) is depending on the water flow condition and the size of forebay.