IMPROVEMENTS IN OR RELATING TO RIVER CONTROL STRUCTURES

Abstract: River control structures, of the kind konwn as upstream tilting gates. A structure in accordance with the invention includes a chamber, (1, 2, 3 and 4), and a tilting platform (5). The upstream end of the platform includes a curved transverse wall (10), consisting of a plurality of leaves (12 and 13). When the platform is raised, the leaves provide a continuous wall between the platform and the top of the chamber, while when the platform is lowered, the leaves slide behind each other and are accommodated in the chamber. The structure also includes a channel (7, 8 and 9), extending along the length of the platform. The channel is provided with baffles to limit the flow of water down the channel, to enable fish to surmount the structure.

Description: IMPROVEMENTS IN OR RELATING TO RIVER CONTROL STRUCTURES This invention relates to river control structures. The term "river" is used herein to include any running stream of water and thus extends, for example, to canals and other watercourses, whether natural or artificial. It is frequently necessary to provide means for controlling the flow of water, for example to provide water storage. Other uses for river control structures include river flow gauging stations and weirs to retain water for irrigation or extraction for public water supply. One particular type of structure which has been used for river control is known as an "upstream tilting gate." This type of structure includes a longitudinally extending platform, the downstream end of which is supported with freedom to rotate about an axis extending across the river, and the upstream end of which is supported by control means adapted to raise and lower that end. The above type of control structure is very simple and effective, but it suffers from the disadvantage that material carried downstream by the flowing water collects beneath the platform and eventually prevents the platform from being lowered. To avoid the problems of blockage and siltation, it has been proposed to provide a depending wall on the upstream edge of the platform. Such wall is normally in the form of part of a surface of a cylinder, the axis of which is coincident with the axis of rotation of the platform. Such a wall can be designed to prevent material from collecting below the platform , but requires considerable construction work to provide a space below the platform to accommodate the wall as the platform is lowered. Accordingly it is an object of one aspect of the present invention to provide a river control structure of the general type referred to above, but which does not suffer from the disadvantage of known gates. t&M. γ T i p o ~ - From this aspect the invention consists in a river control structure comprising a longitudinally extending platform, one end of which is supported with freedom to rotate about an axis extending across the river, and the other end of which is supported by control means adapted to raise and lower said other end, wherein a plurality of leaves extending across th river depend from said other end of said platform in such a way that, as said other end is lowered towards its lowermost position, successive ones o said leaves slide relative to the respective adjacent leaf so that all said leaves can be accommodated below the platform with their lower edges substantially level, whereas, as said other end is raised, the leaves slide relatively to 'form a substantially continuous wall across the river. Preferably a structure in accordance with the invention includes a chamber having an upstream wall, a downstream wall and two side walls. this case the downstream end of the platform is supported by the downstr wall with freedom to rotate about an axis extending parallel to said downstream wall. The leaves depending from the upstream end of the platform cooperate with the upstream wall of the chamber to control the water flow. When the platform is lowered, all the leaves are accommod within the chamber with their lower edges substantially on the bottom of chamber. When the platform is raised, the leaves extend between the upstream edge of the platform and the top of the upstream wall of the chamber. Whenever a new control structure is provided on a migratory fish riv it is necessary to provide suitable conditions for migrating fish to surmount the structure en route to their spawning beds in the upper reach of the river. In the past this has been accomplished by separate fish passes, usually flanking the control structure. It is an object of a second aspect of the present invention to provide an economically and biologically more satisfactory solution to the problem of enabling fish to surmount a river control structure. From this second aspect the invention consists in a river control structure comprising a longitudinally extending platform, the downstream e of which is mounted with freedom to rotate about an axis extending acros the river, and the other, end of which is supported by control means adapt to raise and lower said other end, wherein a baffled channel extends from said one end to said other end of said platform, the baffles being arrange so that, even when said other end of said platform is raised to its maximu height, the water flow down said channel will be not greater than 0.85 metres per second. A considerable study of the jumping and swimming capabilities of fis and in particular of sea trout and salmonids, has shown that a baffled channel, designed to restrict water flow to 0.85 metres per second, can be safely negotiated by migrating fish. In the case of sea trout, the design provides a factor of safety greater than 2. The channel should be designed in such a way that it will contain th turbulent flow caused by the baffles. For this purpose the sides of the channel should extend above the normal water level. These extended side walls will also serve to confine disorientated fish within the channel. Preferably the channel is located substantially on the longitudinal centre line of the platform and normally it will be convenient for the sides of th channel to extend above the upper surface of the platform to approximatel the same extent as they descend below it. The lower end of the channel is preferably designed in such a way as produce turbulence, which will attract the migrating fish. In addition, or alternatively, an additional downstream wall may be provided with a notch the centre of the top of the wall to guide the fish towards the lower end the channel. The baffles may be arranged in any way which will restrict the flow 0.85 metres per second at the maximum inclination required. In particula it has been found that an arrangement known as a "Denil type 19 baffle" restrict flow to this velocity at an inclination of 35 degrees. In fact it would appear that this type of baffle can normally be used safely up to a inclination of 40 degrees. Preferably the features of the first aspect of the invention are incorporated with the features of the second aspect of the invention. Thus, according to a third aspect, the invention consists in a river control structure comprising a chamber having an upstream wall, a downstr wall and two side walls, and a longitudinally extending platform , one end which is supported by said downstream wall with freedom to rotate about horizontal axis extending parallel to said downstream wall, and the other end of which is supported by control means adapted to raise and lower sai other end, wherein a plurality of leaves extending across the width of the chamber depend from said other end of said platform in such a way that, said other end is lowered towards its lowermost position, successive ones o said leaves slide relative to the respective adjacent leaf so that all said leaves can be accommodated within said chamber with their lower edges substantially on the bottom of the chamber, whereas, as said other end is raised, the leaves slide relatively to one another to form a continuous wall across the chamber between said other end of the platform and the top o upstream wall, and wherein a baffled channel extends from said one end t said other end of said platform, the baffles being arranged so that, even when said other end of said platform is raised to its maximum height, the water flow down said channel will be not greater than 0.85 metres per second. Preferably guides are provided in the side walls of the chamber to accommodate the depending leaves. Since the leaves will normally be pa cylindrical, the guides will be arcuate. Preferably seals, ossibl made of rubber or a similar material, will be provided between the sides of the platform and the respective said walls. Preferably holes will be provided in at least some of the leaves to enable water to enter the chamber and t reduce the weight of the platform to be carried by the control means. From yet another aspect the invention consists in any features of novelty, taken singly or in combination, of the river control structure illustrated in the accompanying diagrammatic drawing. The structure illustrated includes a chamber having two side walls, on of which is broken away in the illustration to show the remaining parts of the structure. The other side wall is indicated at 1. The chamber also includes an upstream wall 2 and a downstream wall 3. The downstream w is provided with a ledge 4 on which the platform 5 rests. The platform illustrated includes an upper flat surface and is given the necessary strength by means of a lattice structure indicated at 6. A channel having side walls 7 and 8 and a base 9 extends from the upstream end to the downstream end of the platform. As can be seen fr the drawing, the side walls 7 and 8 extend approximately the same distanc above the upper surface of the platform 5 as they extend below it. Baffl (not shown) are provided in the channel to limit the flow of water down th channel, when the platform is raised to its maximum inclination of 35 degrees, to less than 0.85 metres per second. The upstream end of the platform includes a curved transverse wall 10 This wall is provided with holes 11 to enable water to enter the interior of the chamber below the platform. Two leaves 12 and 13 depend from the 10. As can be seen, when the platform is in its raised position, these leaves provide a continuous wall between the platform and the upper edge o the upstream wall 2. When the platform is lowered, the leaves 12 and 13 slide behind the wall 10 and are accommodated in the chamber as indicated the dashed lines 14. Control means are provided to raise and lower the upstream end of t platform 5 and these are indicated diagram matically as a threaded rod 15, which cooperates with a correspondingly threaded nut secured in the platform. Means (not shown) are provided to rotate the rod 15 to raise lower the platform. Preferably a detector 16 is provided to measure the water level and give a signal, which may be used for automatic control of the inclination of the platform. The wall 10 and the leaves 12 and 13 run in arcuate channels in the side walls, the channel in the side wall 1 being shown at 17. Preferably the edges of the platform 5 are provided with rubber seals (not shown) w cooperate with the side walls of the chamber. To assist the migrating fish to find the entrance to the channel, a wall 18 is provided below the downstream wall 3. This wall has a notch designed to produce turbulence which will guide the fish towards the entrance to the channel.

Claims: CLAIMS: A river control structure comprising a longitudinally extending platform, one end of which is supported with freedom to rotate about an axis extending across the river, and the other end of which is supported by control means adapted to raise and lower said other end, wherein a plurality of leaves extending across the river depend from said other end of said platform in such a way that, as said other end is lowered towards its lowermost position, successive ones of said leaves slide relative to the respective adjacent leaf so that all said leaves can be accommodated below the platform with their lower edges substantially level, whereas, as said other end is raised, the leaves slide relatively to form a substantially continuous wall across the river. A river control structure according to Claim 1, further including a chamber having an upstream wall, a downstream wall and two side walls. A river control structure according to Claim 2, wherein the downstream end of the platform is supported by the downstream wall of the chamber, with freedom to rotate about an axis, extending parallel to said downstream wall. A river control structure according to Claim 3, wherein the arrangement is such that, when the platform is lowered, all the leaves are accommodated within the chamber with their lower edges substantially on the bottom of the chamber, whereas, when the platform is raised, the leaves extend between the upstream edge of the platform, and the top of the upstream wall of the chamber. A river control structure comprising a longitudinally extending platform, the downstream end of which is mounted with freedom to rotate about an axis extending across the river, and the other end of which is supported by control means adapted to raise and lower said other end of said platform, wherein a baffled channel extends from said one end to said other end of said platform, the baffles being arranged so that, even when said other end of said platform is raised to its maximum height, the water flow down said channel will be not greater than 0.85 metres per second. A river control structure according to Claim 5, wherein the sides of the channel extend above the normal water level, so that the channel will contain the turbulent flow caused by the baffles. A river control structure according to Claim 5 or Claim 6, wherein the channel is located substantially on the longitudinal centre line of the platform. A river control structure according to any of Claims 5 to 7, wherein the sides of the channel extend above the upper surface of the platform to substantially the same extent as they descend below it. A river control structure according to any of Claims 5 to 8, wherein the lower end of the channel is designed in such a way as to produce turbulence. A river control structure according to any of Claims 5 to 9, wherein an additional downstream wall is provided, with a notch in the top of the wall, to guide the fish towards the lower end of the channel. A river control structure comprising a chamber having an upstream wall, a downstream wall and two side walls, and a longitudinally extending platform, one end of which is supported by said downstream wall with freedom to rotate about a horizontal axis extending parallel to said downstream wall, and the other end of which is supported by control means adapted to raise and lower said other end, wherein a plurality of leaves extending across the width of the chamber depend from said other end of said platform in such a way that, as said other end is lowered towards its lowermost position, successive ones of said leaves slide relative to the respective adjacent leaf so that all said leaves can be accommodated within said chamber with their lower edges substantially on the bottom of the chamber, whereas, as said other end is raised, the leaves slide relatively to one another to form a continuous wall across the chamber between said other end of the platform and the top of the upstream wall, and wherein a baffled channel extends from said one end to said other end of said platform, the baffles being arranged so that, even when said other end of said platform is raised to its maximum height, the water flow down said channel will be not greater than 0.85 metres per second. A river control structure according to Claim 11, wherein arcuate guides are provided in the side walls of the chamber to accommodate the depending leaves. A river control structure according to Claim 12, wherein seals are provided between the sides of the platform and the respective side walls. A river control structure according to Claim 13, wherein the seals are made of rubber. A river control structure according to any of Claims 11 to 14, wherein holes are provided in at least some of the leaves to enable water to enter the chamber, and thus reduce the weight of the platform to be carried by the control means. A river control structure substantially as herein before described, with reference to, and as illustrated in, the accompanying diagramatic drawing.

Inventors: WOOLNOUGH ANTHONY L, WOOLNOUGH, ANTHONY, L.
Applicants: WOOLNOUGH ANTHONY L, WOOLNOUGH, ANTHONY, L.
Application year: 1984
Main classification: E02B7
IPC codes: E02B7, E02B8