Sluice Gates

The sluice gate is a device used to control the passage of water in an open channel. When properly calibrated, it may also serve as a means of flow measurement (Fig A.1)

Flow through a sluice gate differs fundamentally from flow through a slot in that the jet is not free but guided by a horizontal floor. Consequently, the final jet pressure is not atmospheric, but distributed hydrostatically in the vertical section.

The following pictures are from http://www.allen-marine.com/sluice.html and they show how the sluice gate operates by showing it closed and then open.

Fig A.1 The sluice gate is fully closed at this time. 

Fig A.2 The water is now just starting to flow under the gate as it is slowly being lifted upwards. 

Fig A.3 Here the sluice gate is open and letting the water flow through in a controlled manner under the gate.

Fig A.4 This is a picture of Leonardo da Vincis drop down sluice gate in model form. He originally created it for a water course that was divided into short sections by use of sluice gates with drop-down pieces. It was used to make boats go up and down the water head created by the crosspiece.

Here are just some more pics and explanation of sluice gates

They are used for shutting-off the water flow in waterworks channels. They can be operated manually or automatically, driven mechanically with pin rod, trapezoidal bolt, or hydraulically with a hydraulic cylinder. In this case, the hydraulic circuit is filled with a biologically fully degradable oil.

Sluice plates can be made of wood or steel, in both cases with sliding materials on sealing surfaces. Surfaces are protected by coating or hot dip zinc-coating.

Fig A.5 This is a picture of a sluice gate at Dolo. Here you can see how the sluice gate in the lower right hand corner, helped to monitor the flow of the river in the upper half of the picture.

Typical Sluice Gate Problem in free flow 

Fig B.1 This is the diagram of a typical sluice gate problem. (Fig A.4). You have two distances, your initial height (D1) and your lower height (D2).

2. http://www.cardiff.gov.uk/SPNR/neigh_ren/harbourauthority/barrage/sluice_gates.htm

3. http://www.leonet.it/comuni/vincimus/18ponc_e.html

Sources
1. http://www.museoscienza.org/english/Leonardo/paratoieghigliottina.html

2. http://www.allen-marine.com/sluice.html