Complex sentence: The lake level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile, which regulates the flow to the Blue Nile Falls (Tis Abbai) and hydro-power station.
Split into simpler sentences: The lake level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile. This controls the flow to the Blue Nile Falls (Tis Abbai) and hydro-power station.