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 Tis Abay falls 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 regulates the flow to the Tis Abay falls and hydro-power station.