Abstract: A method and apparatus for controlling an upstream water level by adjusting the elevation of a trough assembly of a weir. The weir is a open frame within which is slidably mounted a trough assembly, which may be raised or lowered by means of a tandem screw jack assembly, which caps the open frame. The perimeter of the open frame is lined with a continuous J-shaped neoprene seal, which provides a smooth slidable surface for movement of the trough assembly. The J-shaped seal also provides a substantially water tight barrier between the trough assembly and the open frame. Two vertical screw shafts extend downwardly from the tandem screw jack assembly and are bolted to the trough assembly. By rotating a hand crank, the vertical screw shafts raise or lower the trough assembly.