GB2464959A

GB2464959A - Flood defence apparatus, system and method

Info

Publication number: GB2464959A
Application number: GB0819980A
Authority: GB
Inventors: Anthony Thornbury; Stuart Gordon Varndell
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-10-31
Filing date: 2008-10-31
Publication date: 2010-05-05
Anticipated expiration: 2028-10-31
Also published as: GB2464959A8; GB2464959B; GB2464959B8; GB0819980D0

Abstract

A flood defence apparatus comprises a channel 10 having a base 12 and side walls 14 and 16 extending downwardly from a surface level opening to the base so as to be adapted to collect and transfer surface liquid. The apparatus further comprises a channel dividing formation 18 extending generally downwardly from the opening of the channel towards but not to the base, so as to divide the channel into a drainage portion 20 open for the access flow of surface liquid and a chamber portion 22 and to define a liquid communicating portion 28 between the drainage portion and the chamber portion below the dividing formation. The apparatus further comprises at least one buoyant barrier member 26 received in the chamber portion to be selectively moveable between a first position within the channel and a second position where the barrier member at least partially extends from the channel. The level of liquid in the drainage portion follows the level of liquid in the chamber portion to allow, in use, varying levels of liquid in the channel to move the barrier member.

Description

Flood Defence Apparatus, System and Method The present invention relates generally to flood defence apparatus for protecting land or buildings and more particularly to flood defence apparatus for installation in the vicinity of land or buildings which are susceptible to flooding by surface liquid, such as rainwater.

Flood defence apparatus are known. Known apparatus make use of complicated mechanical, hydraulic or pneumatic means to raise and lower a moveable flood barrier in times of high water. For example, EP0726364 provides an apparatus for a watercourse, such as a dike, having a moveable flood barrier. In times of high water, the flood barrier can be transferred from a low position towards a high position by water flowing into a chamber within the dike body down an inclined filling channel. As the water level lowers, water flows from the chamber via a discharge channel and the flood barrier moves towards the low position. The filling channel is provided in an upper part of the dike body and the discharge channel is provided in a lower part of the dike body.

This apparatus requires a permanent, above ground structure, such as a dike body. The dike body is both intrusive and an eye sore and is a permanent barrier when water is not present. For example, pedestrians or vehicles are prevented from moving over the barrier when in the low position when there is no risk from flood water. Installation of the apparatus is expensive and time consuming and is limited in its application. Flood water must rise significantly above ground level before the flood barrier is raised.

A first aspect of the present invention provides a flood defence apparatus, comprising: -a channel having a base and side walls extending downwardly from a surface level opening to the base so as to be adapted to collect and transfer surface liquid; -a channel dividing formation extending generally downwardly from the opening of the channel towards but not to the base, so as to divide the channel into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -at least one buoyant barrier member received in the chamber portion to be selectively moveable between a first position within the channel and a second position where the barrier member at least partially extends from the channel.

Advantageously, the channel is adapted to collect and transfer surface liquid from above surface level. Surface liquid may access the channel at least via the drainage portion. Surface liquid is allowed to flow into the channel and be transferred or drained away in a similar manner to an existing drainage channel or gutter, an upper opening of which is provided atgroundlevel.

Where the level of liquid in the channel is below the channel dividing portion, the barrier member is in the first position, and liquid in the channel is entirely within the communicating portion. The communicating portion conveniently allows liquid to flow freely along the base of the channel to be suitably transferred. Liquid collected in the channel may soak away into surrounding earth or a fluid outlet may be provided near the base of the channel and a suitable drainage means attached thereto. The channel conveniently provides an immediate drain for surface liquid to flow, even where the amount of liquid entering the channel is not enough to sufficiently fill the chamber portion and raise the barrier member received therein.

Where a substantial volume of liquid flows into the channel and the level of liquid therein rises up the channel beyond the lowest extent of the dividing formation, liquid enters the chamber portion and moves the buoyant barrier member received therein towards the second position. The liquid level in the chamber portion follows liquid level in the drainage portion to allow, in use, varying levels of liquid in the channel to move the barrier member reversibly between the first position and the second position.

Liquid may still be transferred along the channel whilst the barrier member is being moved by liquid rising in the chamber portion.

The apparatus therefore acts as a conventional drainage channel when the liquid level in the channel is below the channel dividing formation and when the level of liquid in the channel is sufficient to enter the chamber portion and move the barrier member towards the second position.

Advantageously, the apparatus is suitable for many applications which require protection from surface liquid, such as domestic and commercial buildings, car parks or agricultural land. The source of the surface liquid may include tidal watercourses, excess rain water or accidental spillage.

Preferably the channel dividing formation is elongate and arranged along the channel. The channel dividing formation may be arranged in the channel and orientated in a number of ways. For example, the channel dividing formation may divide the channel approximately in half. Suitably the channel dividing formation may extend vertically towards the base of the channel or may be angled relative to the vertical. The channel dividing formation may be removable from the channel to allow access to the barrier member, for example.

Preferably the chamber portion is defined by at least the channel dividing formation and a first side of the channel. In a similar manner, the drainage portion is defined by the channel dividing formation and the opposing second side of the channel.

Conveniently the chamber portion is defined by a chamber housing 1 0 comprising at least the channel dividing formation and a further side wall formation spaced apart therefrom, and comprising means for the at least one barrier member to be received therein.

Preferably the at least one barrier member is slideably mounted in the chamber housing to engage with one or both of the channel dividing formation and the further side wall formation.

Suitably the chamber housing may comprise end walls extending between the channel dividing formation and the further side wall formation. The end walls may be adapted to allow two or more chamber housings to connect together. Suitably the end walls comprise connecting portions to allow a plurality of chamber housings to be connected together. For example, one end wall may comprise a projecting portion which interconnects with a complementarily shaped recess in a second end wall of a chamber housing of another apparatus. Such connecting apparatus may conveniently provide an elongate flood defence system.

Preferably the barrier member is in sealing engagement with the chamber housing when, in use, reversibly moving between the first and second positions. The barrier member suitably engages in sealing manner with one or more of the channel dividing formation, further side wall formation and end walls. Sealing engagement between the barrier member and the chamber housing advantageously prevents liquid from the chamber leaking past the barrier member to surface level and, in particular, a protected side of the apparatus.

Suitably the chamber housing comprises a base member by which the barrier member is supported when in the first position. The base member may simply comprise one or more brackets extending between the 1 0 channel dividing formation and the first side of the channel. Alternatively, the base member may extend substantially between the channel dividing formation and the further side wall formation, the base having one or more apertures to allow liquid to enter the chamber housing when the level of liquid in the channel rises up beyond the lower extent of the channel dividing formation.

Suitably the barrier member comprises a buoyant lower portion. A buoyant lower portion ensures the barrier member is being urged from below towards the second position by rising liquid in the chamber portion.

Suitably the buoyant lower portion has a volume which is greater than a volume of an upper portion of the barrier member. Suitably the barrier member is at least partly hollow. A hollow barrier member is conveniently lightweight and particularly buoyant.

Suitably the barrier member comprises a vertical face and an opposing angled face to define a barrier member having a wedge-like cross section.

Suitably, in use, the angled face may be a wet' side of the barrier member relative to surface liquid accessing the channel and the vertical face may be a dry' side of the barrier member relative to surface liquid entering the channel from which protection is being provided by the apparatus. This arrangement provides a strong barrier member to withstand the loads exerted on the barrier member by surface liquid, particularly when the level of the surface liquid is high relative to the barrier member when in the second position. The loads exerted on the barrier member by a high level of surface liquid will be greater on the lower portion of the barrier member than the loads on the upper portion of the barrier member.

Suitably the barrier member and chamber housing may be complementarily shaped to provide sealing engagement therebetween as the barrier member reversibly moves between the first and second positions. A barrier member having a wedge-shaped cross section provides an effective seal when engaged with a complementarily shaped chamber housing, particularly when the barrier member is in the raised second position.

Suitably the apparatus may comprise a channel cover having a first apertured area to correspond with the drainage portion for surface liquid to drain and a second apertured area adapted to correspond with the chamber portion. The first and second apertured areas may comprise slots arranged along opposing sides of the channel cover. The channel cover desirably provides a suitable and safe surface for pedestrians to walk over or vehicles to move over.

A closure member may be provided to close the second apertured area when the barrier member is in the first position. Suitably the closure member may be mounted to the channel cover by a hinge. A hinged closure member prevents the ingress of debris, such as leaves, into the chamber housing when the barrier member is in the first position within the channel whilst allowing the barrier member to move towards the second position to at least partially extend from the channel.

The first apertured area in the cover may comprise a plurality of drainage apertures. The drainage apertures may be equally spaced. The drainage apertures may be parallel slots. The drainage apertures may be arranged and adapted to prevent the ingress of debris, e.g. leaves, whilst allowing surface liquid to access the channel.

Suitably the a portion of the base of the channel is sloped. The base may be sloped longitudinally and/or transversely relative to the channel.

Preferably the base is sloped transversely from a side of the channel towards a deepest point of the channel. A sloped base advantageously prevents the channel silting up to ensure an unobstructed channel is provided for the surface liquid to flow.

Suitably at least one of the channel sides, channel base, channel dividing formation and barrier member may be formed from a plastics material.

Suitably a plastics material provides resistance to corrosion and is lightweight. A lightweight apparatus also provides for easy installation. A suitable plastic may include urethane.

Alternatively the channel sides and! or channel base may be concrete.

In a first embodiment of the invention, the channel sides and base comprise the sides and base of an optionally lined, sub-surface channel excavation.

In a second embodiment of the present invention, a channel module is provided for fitting in a sub-surface channel excavation, the channel module comprising: -a channel lining having a base and side walls extending downwardly from an opening, for example to be located at a surface level in use, to the base so as to define a channel adapted to collect and transfer surface liquid; -a channel dividing formation extending generally downwardly from the opening of the channel lining towards but not to the base, so as to divide the channel lining into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -at least one buoyant barrier member received in the chamber portion to be selectively moveable between a first position within the channel lining and a second position where the barrier member at least partially extends from the channel lining.

The sub-surface channel excavation may be an existing drainage channel, e.g. a prefabricated concrete drainage channel, or may be purposively excavated for the channel module to be fitted. For example, the channel module may conveniently be fitted into an existing drainage channel or may be retrofitted around an existing building or installed in an excavated channel when the building is built. Suitably the channel module is sized according to the size of the sub-surface channel excavation in which it is to be fitted in, for example where the channel is an existing channel, or the sub-surface channel excavation is suitably sized in accordance with the channel module, for example a channel specifically excavated for the channel module. Suitably the channel module sits in the channel and is flush with the surface level, the only visible aspect being the opening of the channel lining. This allows surface fluid to drain into the channel lining. The channel module operates in the same manner as the apparatus as described above.

Preferably the channel module further comprises first and second end walls adapted to allow the first end wall of a channel module to connect to the second end wall of another channel module to allow a plurality of channel modules to connect together. A first end wall may be complementarily shaped with a corresponding second end wall. The channel dividing formation is preferably mounted or attached to the end walls. Suitably the channel dividing formation may be removable from the channel module to allow access to channel lining or barrier member, for example. The channel dividing formation may be slideably mounted to the channel lining and engage with downwardly extending slots in the end walls of the module, for example.

Preferably the first end wall of the channel module comprises a fluid inlet adapted to sealably engage with a fluid outlet provided in the second end wall of another channel module. Suitably the fluid inlet and fluid outlet being provided near the base of its corresponding channel module.

Conveniently, a plurality of channel modules may be fluidly connected in series to provide a continuous flow path for surface liquid to be transferred. Suitably the chamber portions of adjacent channel modules may be fluidly connectable. Suitably the barrier members of adjacent channel modules may be connectable.

One or more sealing members may be provided to seal a gap between adjacent barrier members of neighbouring channel modules.

In a further aspect of the present invention, the channel may conveniently be an existing drainage channel, e.g. a prefabricated concrete drainage channel, into which at least the channel dividing member is fitted to define the chamber portion in which at least one barrier member is received.

This aspect of the invention provides a flood defence kit for fitting into an existing drainage channel to create a flood defence apparatus as described above, the kit comprising: -a channel dividing formation extending generally downwardly from an opening of the channel towards but not to the base, so as to divide the channel into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -at least one buoyant barrier member received in the chamber portion to be selectively moveable between a first position within the channel and a second position where the barrier member at least partially extends from the channel.

The channel may be an excavated channel or may be a prefabricated channel which is arranged in an excavated channel. The channel may be an existing channel or may be excavated during construction of a building, for example, or where the apparatus is retrofitted to protect an existing building or plot of land.

Suitably the channel dividing formation is suspended from a channel cover. Alternatively, the channel dividing formation may be attached to end walls of the channel. As described above, the channel dividing formation divides the channel into a drainage portion and a chamber portion in which the barrier member is received. The drainage portion and chamber portion are fluidly connected by the communicating portion to allow liquid to enter the chamber portion when the liquid level in the channel is sufficient. The liquid level in the chamber housing follows liquid level in the drainage portion to allow, in use, varying levels of liquid in the channel to move the barrier member reversibly between the first position and the second position. The communicating portion below the channel dividing formation conveniently allows any level of liquid to be transferred along the channel and drained to soak from the channel or via suitable drainage means.

A further aspect of the present invention provides a flood defence system comprising a plurality of apparatus or channel modules as described above disposed serially, and for example connected in series, to define an elongate flood defence system. The flood defence system may be provided in front of or around an area of a building to be protected. An apparatus or system may be provided in the vicinity of weak areas of a building, such as doors and windows, for example. Advantageously, the barrier member does not require support means when moving from the first position to the second position, such as undesirably using the building as the support means. The building may be domestic or commercial. The system may be retrofitted around an existing building or installed when the building is initially built. The system may be provided between flood resistant walls to provide an access point or gateway when the barrier member is in the lowered first position whilst providing a continuous flood barrier with the walls when the barrier member is in the raised second position.

One or more sealing members may be provided to seal a gap between adjacent barrier members of neighbouring adjoined apparatus or modules.

A further aspect of the present invention provides a drainage system comprising an apparatus or a system as described above.

A further aspect of the present invention provides a method of installing a flood defence apparatus, comprising the steps of: -providing a drainage channel having a base and side walls extending downwardly from a surface to the base so as to be adapted to collect and transfer surface liquid; -providing a channel dividing formation extending generally downwardly from an opening of the channel towards but not to the base, so as to divide the channel into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; -providing at least one buoyant barrier member received in the chamber portion to be selectively moveable between a first position within the channel to a second position where the barrier member at least partially extends from the channel; whereby liquid level in the chamber portion follows liquid level in the drainage portion to allow, in use, varying levels of liquid in the channel to move the barrier member reversibly between the first position and the second position.

The method may further comprise the step of connecting two or more flood defence apparatus together in fluid communication to provide a flood defence system.

The method may further comprise the step of providing one or more sealing members to seal a gap between adjacent barrier members of neighbouring apparatus.

In a possible embodiment, the method of the invention provides a method of installing a channel module into a sub-surface channel excavation is provided, the method comprises the steps of: -providing a channel module comprising: -a channel lining having a base and side walls extending downwardly from a surface so as to be adapted to collect and transfer surface liquid; -a channel dividing formation extending generally downwardly from 1 0 an opening of the channel lining towards but not to the base, so as to divide the channel lining into a drainage portion open for the access flow of surface liquid and a chamber housing and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -at least one buoyant barrier member received in the chamber housing to be selectively moveable between a first position within the channel lining and a second position where the barrier member at least partially extends from the channel lining; and -installing the channel module in the sub-surface channel excavation.

The method of installing a channel module into a sub-surface channel excavation may further comprise one or more of the following steps: -providing a cover having a first aperture for surface liquid to drain and a second aperture adapted to correspond with the upper opening of the chamber housing; -connecting two or more channel modules together in fluid communication to provide a flood defence system; and -providing one or more sealing members to seal a gap between adjacent barrier members of neighbouring apparatus.

In another possible embodiment, the method of the invention provides a method of installing a flood defence kit into an existing drainage channel to create a flood defence apparatus as described above, the channel having a base and side walls extending downwardly from a surface so as to be adapted to collect and transfer surface liquid, comprising the steps of: -providing a channel dividing formation extending generally downwardly from an opening of the channel towards but not to a base, so as to divide the channel into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -slideably mounting at least one buoyant barrier member in the chamber portion to be selectively moveable between a first position within the channel to a second position where the barrier member at least partially extends from the channel; whereby liquid level in the chamber portion follows liquid level in the drainage portion to allow, in use, varying levels of liquid in the channel to move the barrier member reversibly between the first position and the second position.

The channel may be a channel excavated in front of or around the area of a building to be protected. Alternatively, the channel may be an existing drainage channel, as described above. Desirably, the channel is a depth and width to allow the barrier member to be wholly contained in the channel when in the first position to provide a flat upper surface level with the ground surface.

The method of installing a flood defence kit into an existing drainage channel to create a flood defence apparatus as described above may further comprise any one of the following steps: -providing a chamber housing comprising at least the channel dividing formation and a further side wall formation spaced apart therefrom and adapted to receive the barrier member; and -providing a cover having a first aperture for surface liquid to drain and a second aperture adapted to correspond with the upper opening of the chamber portion.

The method of installing a flood defence kit into an existing drainage channel to create a flood defence apparatus as described above may further comprise any one of the following steps: -connecting two or more chamber housings together in fluid communication; and -providing one or more sealing members to seal a gap between adjacent barrier members of neighbouring kits.

The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: -Figure 1 is an isometric representation of an embodiment of a channel module according to the present invention showing a section through the module; -Figure 2 shows an end view of the module of Figure 1 when the barrier member is between the first and second positions; -Figure 3 shows a side of another embodiment of the channel module; -Figure 4 shows an opposite side of the channel module of Figure 3; -Figure 5 shows a flood defence system of channel modules as shown in Figure 4; and -Figure 6 shows the flood defence system of Figure 5 with the barrier members in the raised second position.

As shown in Figures 1 and 2, a channel module 1 for fitting in a sub-surface channel excavation comprises a channel lining 10 having a base 12 and side waIls 14, 16 extending downwardly from a surface so as to be adapted to collect and transfer surface liquid, such as rainwater, floodwater or accidental spillage.

A channel dividing formation 18 extends generally downwardly from an opening of the channel lining 10 towards but not to the base 12 so as to divide the channel lining 10 into a drainage portion 20 open for the access flow of surface liquid and a chamber portion 22 and to define a liquid communicating portion 24 between the drainage portion 20 and the chamber portion 22 below the channel dividing formation 18. The channel dividing portion 1 8 and the side wall 1 6 of the channel lining 1 0, and a chamber base 21, define a chamber housing 22. Conveniently, the channel dividing formation 18 may be removable from the channel module 1 to allow access to the channel lining 1 0 for cleaning purposes, for

example.

A buoyant barrier member 26 is slideably mounted in the chamber housing 22. The chamber housing 22 has an aperture 28 in its base 21 to fluidly connect the chamber housing 22 with the drainage portion 20 of the channel 10. This allows rising liquid in the channel lining 1 0 to enter and fill the chamber housing 22 and also exit the chamber housing 22 when the liquid level in the channel 10 lowers. Liquid level in the chamber housing 22 thereby follows liquid level in the drainage portion 20.

Therefore, varying levels of liquid in the channel 1 0 moves the barrier member 26 reversibly between a first position within the channel liningi 0 to a second position where the barrier member 26 at least partially extends from the channel lining 10. A removable channel dividing formation 18 may also allow access to the barrier member 26 to allow the same to be removed from the channel module 1 for maintenance purposes, for example.

Advantageously, the channel lining 1 0 is adapted to collect and transfer liquid from ground level. Surface liquid is allowed to flow into the channel lining 10 and be transferred or drained away in a similar manner to an existing drainage channel or gutter, an upper opening of which is provided at ground level. Where excess liquid, such as excess rainwater, flows from the surface into the channel lining 1 0, the liquid level in the channel lining 10 rises to enter the chamber housing 22 and move the barrier member 26 slideably mounted therein towards the second position.

Conveniently, the communicating portion 24 between the drainage portion and the chamber housing 22 below the dividing formation 18 allows liquid to flow freely along the channel lining 1 0 thereby to be suitably transferred to ground or via suitable drainage means. Liquid may continually be transferred along the channel lining 1 0 below the channel dividing formation 18 whilst the barrier member 26 is being moved by liquid filling the chamber housing 22. The channel module 1 therefore acts as a conventional drainage channel for any amount of surface liquid, e.g. when the surface liquid entering the channel lining 1 0 is minimal and when excess surface liquid enters the channel lining 1 0 and the barrier member 26 is moved towards the second position, for example in adverse weather conditions.

The channel module 1 advantageously provides an immediate drain for surface liquid to flow, even where the amount of liquid entering the channel lining 1 0 is not enough to sufficiently fill the chamber housing 22 and raise the barrier member 26 mounted therein.

Advantageously, the channel module 1 is suitable for many applications which require protection from surface liquid, such as domestic and commercial buildings, car parks or agricultural land. The source of the surface liquid may include tidal watercourses, excess rain water or accidental spillage.

The barrier member 26 has a wedge-shaped cross section having a vertical face 30 on a protected dry' side and an angled face 32 on a wet' side of the channel module 1. This arrangement provides a strong barrier member 26 to withstand the loads exerted thereon by surface liquid, particularly when the level of the surface liquid is high relative to the barrier member 26 when in the second position. The barrier member 26 is hollow and made from a plastics material such as urethane to provide a lightweight and particularly buoyant barrier member 26.

The barrier member 26 engages with the channel dividing formation 18 and side wall 1 6 of the channel lining 1 0 which define the chamber housing 22 as it moves between the first and second positions. The engagement is a sealing engagement to prevent liquid from the chamber housing 22 leaking past the barrier member 26 to surface level and, in particular, the protected side of the channel module 1. The chamber housing 22 may be complimentarily shaped with the barrier member 26 to provide an effective seal therebetween.

A cover 34 is fitted to the opening of the channel lining 1 0 having a first slot 36 provided along one side wall 14 of the channel lininglO for surface liquid to drain into the channel lining 1 0 and a second slot 38 provided along an opposite side wall 16 of the channel lining 10 adapted to correspond with the upper opening of the chamber housing 22 to allow the barrier member 26 to extend from when moving towards the second position. A closure member 35 (shown in Figure 3) may be provided to close the second slot 38 when the barrier member 26 is in the first position. The closure member may be mounted to the cover 34 by a hinge or may alternatively be integral with the barrier member 26 to rise and fall therewith. A closure member 35 prevents the ingress of debris, such as leaves, into the chamber housing 22 when the barrier member 26 is in the first position. The cover 34 and closure member 35 desirably provide a flat surface suitable for pedestrians to walk over and/or vehicles to move over.

The first slot 36 in the cover 34 includes a plurality of drainage apertures 40. The apertures 40 are equally spaced, parallel slots. The drainage apertures 40 prevent the ingress of debris, e.g. leaves, whilst allowing surface liquid to access the channel lining 1 0. Alternatively, as shown in Figure 3, the first and second slots may be covered by a separate cover 33 and closure member 35, respectively. An intermediate cover portion 37 may be provided between the cover 33 and closure member 35 to provide a continuous flat surface for pedestrians to walk over and/or vehicles to move over.

A part 1 3 of the base 12 of the channel lining 1 0 is sloped transversely from side wall 16 towards a deepest point of the channel lining 10 to advantageously prevent the build up of silt in the channel lining 10 and to ensure an unobstructed path is provided for the surface liquid entering the channel lining 10 to flow.

The channel lining 10 may be formed from a plastics material. A plastics material is resistant to corrosion and is lightweight. A lightweight channel module 1 also provides for easy installation. A suitable plastic may include urethane.

As shown in Figures 3, the channel module 1 comprises first and second end walls 42, 44 adapted to allow the first end wall 42 of a channel module to connect to the second end wall 44 of another channel module to allow a plurality of channels modules 1 to connect together in series to provide an elongate flood defence system. The first end wall 42 of one channel module 1 has at least one projecting portion 43 which is shaped to interconnect with at least one complementarily shaped recess 45 in the second end wall 44 of another channel modulel to allow the channel linings 10 to connect together and provide an elongate flood defence system 50, as shown in Figure 5.

As shown in Figure 4, the end waIls 42, 44 may comprise an aperture 45 which allows adjacent chamber housings 22 to fluidly connect together.

The barrier members 26 may comprise a projection 47 on a first vertical side thereof which is adapted to interconnect with a complementarily shaped recess on a second vertical side of an adjacent barrier member 26 of a neighbouring channel module 1. Neighbouring channel modules 1 are fluidly connected to provide a combined drainage channel and flood defence system 50, as shown in Figures 5 and 6.

The flood defence system 50 may be provided in front of or around an area of a building to be protected. One or more channel modules 1 may be provided in the vicinity of weak areas of a building, such as doors and windows, for example. Advantageously, the module 1 or system 50 of connected modules is substantially maintenance free due to the simplicity of its automatic operation. The barrier member 26 does not require support means when moving from the first position to the second position, such as undesirably using the building as the support means. The building may be domestic or commercial. A system 50 of channel modules 1 may be retrofitted around an existing building or installed when the building is initially built. The system 50 may be provided between flood resistant walls to provide an access point or gateway when the barrier member 26 is in the lowered first position whilst providing a continuous flood barrier with the walls when the barrier member 26 is in the raised second position.

One or more sealing members may be provided to seal a gap between adjacent barrier members 26 of neighbouring connected channel modules 1.

To install a channel module 1, as described above, a channel is first provided having a base and side walls extending downwardly from a surface so as to be adapted to collect and transfer surface liquid. The channel optionally may be lined with plastic or concrete, for example.

Secondly, a channel module 1 as described above is provided and installed in the channel. Two or more channel modules 1 may be connected together to provide a flood defence system 50, as described above. One or more sealing members may be provided to seal a gap between adjacent barrier members 26 of neighbouring channel modules 1 in the system 50.

Claims

Claims 1. A flood defence apparatus, comprising: -a channel having a base and side walls extending downwardly from a surface level opening to the base so as to be adapted to collect and transfer surface liquid; -a channel dividing formation extending generally downwardly from the opening of the channel towards but not to the base, so as to divide the channel into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -at least one buoyant barrier member received in the chamber portion to be selectively moveable between a first position within the channel and a second position where the wall member at least partially extends from the channel.
2. An apparatus according to claim 1, wherein the chamber portion is defined by at least the channel dividing formation and a first side of the channel.
3. An apparatus according to claim 2, wherein the chamber portion is defined by a chamber housing comprising at least the channel dividing formation and a further side wall formation spaced apart therefrom, and comprising means for the at least one barrier member to be received therein.
4. An apparatus according to claim 3, wherein the at least one barrier member is slideably mounted in the chamber housing to engage with one or both of the channel dividing formation and the further side wall formation.
5. An apparatus according to claim 4, wherein the chamber housing comprises end walls extending between the channel dividing formation and the further side wall formation.
6. An apparatus according to claim 5, wherein the end walls are adapted to allow a plurality of chamber housings to be connected 1 0 together.
7. An apparatus according to any one of claims 4 to 6, wherein the chamber housing comprises a base member by which the barrier member is supported when in the first position.
8. An apparatus according to any one of claims 3 to 7, wherein the barrier member is in sealing engagement with the chamber housing when, in use, reversibly moving between the first and second positions.
9. An apparatus according to any preceding claim, wherein the barrier member comprises a buoyant lower portion.
10. An apparatus according to claim 9, wherein the barrier member comprises a vertical face and an angled face to define a barrier member having a wedge-like cross section.
11. An apparatus according to any one of claims 8 to 10, wherein the barrier member and chamber housing are complementarily shaped to provide sealing engagement therebetween as the barrier member reversibly moves between the first and second positions.
12. An apparatus according to any preceding claim, wherein the apparatus comprises a channel cover having a first apertured area to correspond with the drainage portion for surface liquid to drain and a second apertured area adapted to correspond with the chamber portion.
13. An apparatus according to claim 12, wherein a closure member is provided to close the second apertured area when the barrier member is in the first position.
14. An apparatus according to any preceding claim, wherein the base of the channel is sloped transversely from a side of the channel towards a deepest point of the channel.
15. An apparatus according to any preceding claim, wherein the channel sides and base comprise the sides and base of an optionally lined, sub-surface channel excavation.
16. A flood defence kit for fitting into an existing drainage channel to create a flood defence apparatus according to any one of claims 1 to 15, the kit comprising: -a channel dividing formation extending generally downwardly from an opening of the channel towards but not to the base, so as to divide the channel into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -at least one buoyant barrier member received in the chamber portion to be selectively moveable between a first position within the channel and a second position where the barrier member at least partially extends from the channel.
1 7. A channel module for fitting in a sub-surface channel excavation to create an apparatus according to any one of claims 1 to 15, the channel module comprising: -a channel lining having a base and side walls extending downwardly from an opening, for example to be located at a surface level in use, to the base so as to define a channel adapted to collect and transfer surface liquid; -a channel dividing formation extending generally downwardly from the opening of the channel lining towards but not to the base, so as to divide the channel lining into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -at least one buoyant barrier member received in the chamber portion to be selectively moveable between a first position within the channel lining and a second position where the barrier member at least partially extends from the channel lining.
1 8. A channel module according to claim 17, further comprising first and second end walls adapted to allow the first end wall of a channel module to connect to the second end wall of another channel module to allow a plurality of channel modules to connect together.
1 9. A channel module according to claim 18, wherein the first end wall of the channel module comprises a fluid inlet adapted to sealably engage with a fluid outlet provided in the second end wall of another channel module.
20. A method of installing a flood defence apparatus, comprising the steps of: -providing a drainage channel having a base and side walls extending downwardly from a surface to the base so as to be adapted to collect and transfer surface liquid; -providing a channel dividing formation extending generally downwardly from an opening of the channel towards but not to the base, so as to divide the channel into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -providing at least one buoyant barrier member received in the chamber portion to be selectively moveable between a first position within the channel to a second position where the wall member at least partially extends from the channel; whereby liquid level in the chamber portion follows liquid level in the drainage portion to allow, in use, varying levels of liquid in the channel to move the barrier member reversibly between the first position and the second position.
21. A method according to claim 20 comprising the steps of: -providing a channel module comprising: -a channel lining having a base and side walls extending downwardly from a surface so as to be adapted to collect and transfer surface liquid; -a channel dividing formation extending generally downwardly from an opening of the channel lining towards but not to the base, so as to divide the channel lining into a drainage portion open for the access flow of surface liquid and a chamber housing and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -at least one buoyant barrier member received in the chamber housing to be selectively moveable between a first position within the channel lining and a second position where the barrier member at least partially extends from the channel lining; and -installing the channel module into a sub-surface channel excavation.
22. A method according to claim 20 comprising the steps of: -inserting a channel dividing formation extending generally downwardly from an opening of the channel towards but not to the base, so as to divide the channel into a drainage portion open for the access flow of surface liquid and a chamber portion and to define a liquid communicating portion between the drainage portion and the chamber portion below the dividing formation; and -slideably mounting at least one buoyant barrier member in the chamber portion to be selectively rnoveable between a first position within the channel to a second position where the barrier member at least partially extends from the channel; whereby liquid level in the chamber portion follows liquid level in the drainage portion to allow, in use, varying levels of liquid in the channel to move the barrier member reversibly between the first position and the second position.