Gate, leaf and method for controlling water levels in a body of water

Abstract

A gate, leaf, and method for controlling water levels in a body of water. The gate comprises a moveable barrier (which may be a leaf), a restoring device such as a spring, and a profile. The barrier automatically opens or closes an amount to allow less or more water through as a result of changes in the water pressure in the upstream body of water. This helps maintain a water level in the upstream body of water. The profile disturbs the flow of water through the gate to influence the water pressure on the barrier. The profile may help provide a more linear curve for the water moment on the barrier across the range of barrier positions. A more linear curve for the water moment may help maintain equilibrium with the restoring moment across the range of barrier positions. The method comprises disturbing the flow of water over a barrier to redistribute the pressures of the water on the barrier.

We claim: 
     
         1 . A gate for controlling a flow of water from a body, comprising:
 a leaf configured to be moved between an open position and a closed position;   a restoring device configured to bias the leaf towards the closed position; and   a profile configured to disturb the flow of water through the gate for influencing the water pressure on the leaf.   
     
     
         2 . The gate of  claim 1 , wherein the profile is a trough. 
     
     
         3 . The gate of  claim 2 , wherein an upstream surface of the leaf defines the trough. 
     
     
         4 . The gate of  claim 1 , wherein the restoring device is a spring. 
     
     
         5 . The gate of  claim 1 , wherein the leaf is hinged at a lower end for rotating about a horizontal axis between the open position and the closed position. 
     
     
         6 . The gate of  claim 1 , further comprising a base plate connected to the leaf, the base plate for fitting over an existing stop log in a spillway. 
     
     
         7 . The gate of  claim 1 , wherein the profile is configured to influence the pressure distribution of the water on the leaf according to the rate at which water flows over the leaf. 
     
     
         8 . The gate of  claim 1 , wherein the profile is configured to cause the moment of the water on the leaf to increase substantially linearly from a first position to a second position. 
     
     
         9 . The gate of  claim 5 , wherein the profile and the restoring device are configured to cause the leaf to automatically rotate to an angular position which permits a rate of water flow through the gate that is proportional to the rate at which water is accumulating in the body. 
     
     
         10 . The gate of  claim 1 , wherein the profile comprises a curved surface which influences the pressure distribution of the water on the leaf such that the moment varies constantly across the range of angular positions of the leaf. 
     
     
         11 . A method for controlling a flow of water from a body, comprising
 providing a leaf biased towards a closed position to inhibit the flow of water from the body; and   influencing the pressures of the water on the leaf to provide a substantially linear increase in the moment of the water on the leaf in response to the leaf moving towards an open position.   
     
     
         12 . The method of  claim 11 , comprising disturbing the flow of water over the leaf to influence the pressures of the water on the leaf. 
     
     
         13 . A method for controlling a water level in an upstream body of water, comprising allowing for continuous adjustment of the flow of water out of the upstream body of water at the same rate as water accumulates in the upstream body of water. 
     
     
         14 . A method for maintaining a water level, comprising automatically allowing a top edge of a barrier retaining an upstream body of water to lower in response to an increase in the rate of water accumulating in the body. 
     
     
         15 . A method for converting a gated stop log spillway, comprising
 removing one or more stop logs from the spillway,   providing a gate comprising a leaf, the lower end of the leaf attached to a base plate with a hinge, the leaf biased towards a closed position with a spring disposed about the hinge; and   affixing the base plate to the top of the remaining stop logs in the spillway.   
     
     
         16 . The method of  claim 15 , wherein the base plate comprises a C-shaped shoe, and affixing the base plate comprises fitting the shoe over at least the top stop log. 
     
     
         17 . A leaf for a gate to control a water level in a body of water, the leaf comprising a profile configured to disturb the flow of water passing over the leaf to influence the water pressure on the leaf. 
     
     
         18 . The leaf of  claim 17 , wherein the profile is a trough.