GB2540331A

GB2540331A - Flood prevention system and method

Info

Publication number: GB2540331A
Application number: GB1504764.0A
Authority: GB
Inventors: Hannah Smith Alexis
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-03-20
Filing date: 2015-03-20
Publication date: 2017-01-18
Also published as: GB201504764D0; WO2016151290A1; US20160273181A1; GB201604557D0; GB2539064A

Abstract

The system 100 includes a perimeter barrier 14 around a zone 22 to be protected and a soak way system 32-34 disposed sub-surface within the protected zone 22 and designed to collect surface water from within the protected zone 22. A sump 30 is provided within the protected zone 22 and includes a pump 170 for pumping water from the sump outside the protected zone 22 beyond the perimeter barrier 14. A series of sensors 102-106 senses the presence of ground water inside and outside the protected zone 22 and within the sump 30. A control unit 108 is coupled to the sensors 102-108 and controls the operation of the pump 170 in order to remove water from the sump 30 at a rate sufficient for preventing flooding within the protected zone 32. The control unit 108 can provide warning of impending flooding. A later embodiment relates to a method of preventing flooding using said system.

Description

FLOOD PREVENTION SYSTEM AND METHOD Field of the Invention

The present invention relates to a flood control system and method and in the preferred embodiments to a system and method able to prevent floodwater ingress into a dwelling or other building or location within a protected zone.

Background of the Invention

Flooding is a phenomenon which is experienced in many countries and has devastating consequences on inhabitants and businesses. Environmental changes are also bringing flooding to areas not previously affected and increasing flooding to flood prone zones. A variety of flood defences have been developed, most of which involve the construction of permanent high barriers around a zone to be protected, as well as more traditional approaches such as use of sand bag barriers. Such approaches, while able to mitigate the effects of flooding to some degree, are often not effective, particularly when flooding causes an increase in the water table within the area sought to be protected.

Summary of the Present Invention

The present invention seeks to provide an improved system and method of preventing flooding within a protected zone and in the preferred embodiments a system which optimises flood water management.

According to an aspect of the present invention, there is provided a flood management system for protecting a zone from flood water, including: a perimeter barrier disposed around a protected zone, the barrier including an upstanding wall for blocking surface water ingress into the protected zone and a subsurface barrier wall; a drainage system within the protected zone including at least one drainage unit disposed subsurface and adjacent the subsurface barrier wall; and a sump to which the drainage system is fluidically coupled for collecting water from the drainage system.

The at least one drainage unit is preferably a drainage channel, although in some embodiments could be a bore hole of other drainage mechanism, coupled to a sump. As the preferred embodiments use drainage channels, they are referred to as such in what follows, though it is to be understood that systems could be designed with such other drainage mechanisms, as the skilled person will be able to envisage readily having regard to the teachings herein.

Preferably, the or each drainage channel is spaced from the subsurface barrier wall. Most preferably, the or each drainage channel is spaced from the subsurface barrier wall by a distance permitting flow of ground water passing under the subsurface barrier wall into the channel or channels. In a practical embodiment, the or each drainage channel is spaced around one metre form the subsurface barrier wall. There may be provided other drainage channels, or units, further into the protected zone.

The or at least one drainage channel may be open at a top thereof at least adjacent the sump. The or at least one drainage channel may be connected to the sump at a depth lower than a threshold water level. In practice, this arrangement can allow for rain water to be drained naturally into the ground, by spilling out of the drainage channel or channels without operating any pumping unit in the sump, which can save substantial energy usage.

The threshold water level is an acceptable water table level in the protected zone. In practice this can be a level at which the water table does not rise above ground level, that is does not lead to flooding in the protected zone. In some embodiments, the threshold level may be chosen to be below ground level.

Advantageously, the system includes a pumping unit disposed to pump water from the sump to outside the protected zone. The pumping unit may include one or a plurality of pumps. In an embodiment, both pumps are activated when water flow is determined to exceed a threshold rate.

The system may include a water level sensor disposed to measure water level in the sump. The water level sensor may be a hydrostatic sensor.

Preferably, the system includes one or more sensors for measuring surface or ground water inside the protected zone and/or one or more sensors for measuring surface or ground water outside the protected zone. These sensors may also be hydrostatic sensors.

Advantageously, the system includes a control unit coupled to the sensor or sensors. The control unit may be disposed in the protected zone. Preferably, the control unit includes a telemetry unit operable to monitor and manage water levels and pump unit activity. The telemetry system may include a communications unit operable to send flood related alerts and/or alarms.

The system may also include a remote management station communicatively coupled to the or a control unit.

According to another aspect of the present invention, there is provided a method of preventing flooding to a protected zone including the steps of: forming a perimeter barrier around a zone to be protected, the barrier including an upstanding wall for blocking surface water ingress into the protected zone and a subsurface barrier wall; forming a drainage system within the protected zone, the drainage system including at least one drainage channel disposed subsurface and adjacent the subsurface barrier wall; disposing a sump to which the drainage system is fluidically coupled for collecting water from the drainage system.

Advantageously, the method includes the step of determining water porosity of soil where the perimeter barrier is to be formed and determining the depth of the subsurface barrier wall on the basis of the determined soil porosity. Preferably, the subsurface barrier wall is formed to have a greater depth in porous soil and a lesser depth in less porous soil.

In a preferred embodiment the method includes the step of spacing the drainage channel or channels from the perimeter barrier. The method may include the step of determining the spacing of the drainage channel or channels on the basis of the porosity of the soil.

Advantageously, the method includes the step of determining the depth at which the drainage channels are formed on the basis of determined soil porosity.

Preferably, the method includes the step of determining the size or the drainage channel or channels on the basis of determined or estimated water flow.

The method may include the step of providing a pumping unit in the protected zone and fluidically coupling the pumping station to the sump system, the pumping unit including at least one outlet extending beyond the barrier to remove collected water out of the protected zone.

The preferred embodiments of system disclosed herein can provide: a) a barrier built around a property or other area to be protected, which prevents surface water entering the protected area whilst allowing access for pedestrians and vehicles; b) a drainage system that removes ground water from below and surface water from above the property; c) a pumping system that evacuates collected water to outside the barrier; d) a local control system that operates the pumping station; e) a telemetry system that allows remote management of the system and for instance SMS and email alerts to designated recipients.

Other aspects and advantages of the teachings herein are disclosed in the following specific description.

Summary of the Drawings

Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of a flood defence system according to an embodiment of the invention;

Figure 2 is a plan view of the detail of an example of a part of a flood defence system according to the invention;

Figure 3 is a plan view of the detail of a part of a flood defence wall according to the invention;

Figure 4 is a plan view of the detail of an example of a part of a flood defence system similar to Figure 2 and showing a plurality of sensor elements;

Figure 5 is a transverse cross-sectional view of a part of a flood defence wall of the embodiment of Figure 4;

Figure 6 is a cross-sectional view of an embodiment of sump for the system taught herein;

Figure 7 is a cross-sectional view of another embodiment of sump for the system taught herein; and

Figure 8 is a schematic diagram of a control unit for the system taught herein.

Description of the Preferred Embodiments

There are described below various embodiments of flood defence system to illustrate the teachings herein. The skilled person will appreciate that the specific design, shape and dimensions of the various elements of the system will be dependent upon the zone to be protected and the nature of the flood risk.

Referring first to Figure 1, this shows in schematic form an embodiment of flood defence system 10 for protecting a building, such as a dwelling, 12 from being flooded. The system 10 includes a perimeter barrier 14 which surrounds the building 12 and specifically a protected zone 22. The barrier 14 may include (not shown) one or more access points, such as openable flood gates, for gaining access to the protected zone 22 and any building or buildings 12 located within the zone 22. Flood gates and other access points will provide openable or removable fluid impermeable panels disposable in associated openings in the wall 14. The teachings herein are not directed to flood gates or other removable barriers and these are therefore not described in detail herein.

The perimeter barrier 14 includes a first upstanding wall 16, which is constructed to have a height sufficient to be greater than the maximum expected height of surface flood water 18. The barrier 14 also includes a buried footing 20 which acts not only as a support foundation for the upstanding wall 16 but also as an subsurface barrier wall useful in reducing the level of the water table within the protected zone 22, as is explained in detail below.

The perimeter barrier 14, and in particular the upstanding wall 16 and the buried footing 20, may have varying heights and depths in dependence upon the lay of the land around the perimeter of the protected zone 22, so may be greater in cases where parts of the land is at a lower altitude, and lesser where the land that is at a greater altitude, for example. Furthermore, the depth of the buried footing 20 may also be varied in dependence upon the nature of the ground. Specifically, the subsurface barrier 20 has a depth which controls the flow of ground water into the protected zone 22 and the amount of ground water permitted within the protected zone 22, as is explained in detail below. Typically, the footing 20 will be deeper in more porous soil and shallower in less porous soil. Where the soil is impervious, the footing may be very shallow and in some instances omitted.

Within the protected zone 22 there is provided at least one buried channel or drain 32, 34 and these preferably extend alongside but are spaced from the perimeter wall 14, and are coupled to a sump 30, which is a buried water collection chamber.

The sump 30 has dimensions, in terms of depth and diameter, which enable the sump 30 to store sufficient quantities (volume) of collected water before being pumped out of the sump 30, and also for retaining the level of water within the sump 30 to below a preferred level, indicated in the drawings by reference numeral 40. This will in practice, as is explained below, provide a limit to the water table within the protected zone 22. Disposed within the sump 30 is a pumping unit, also described in further detail below, and a conduit or tubing for taking water out of the protected zone 22, as depicted by the arrow 44 in Figure 1.

The drains 32 and 34 are disposed at a depth consistent with the depth of the subsurface barrier 20, typically being at substantially the same depth although may be slightly higher or lower than this, as is explained below. The drains 32, 34 are also spaced from the subsurface barrier 20 to allow for ground water from outside the protected zone to flow into the drain 34, as depicted by arrow 46. Typically, the drains 32, 34 will be around one metre from the subsurface barrier 20, although this will be dependent upon the porosity of the soil.

The drains are typically buried open channels able to allow the flow of water therealong, and are connected to the sump 30 so that the water they collect is fed into the sump 30 for removal from the protected zone 22.

Prior to installation of the system 10 one or more surveys are undertaken around the property 12, the perimeter of the protected zone and the ground within the protected zone, as well as the local environment. These surveys are intended to determine factors such as: mean water table level, soil state and geological composition, particularly soil permeability, historical risk of flooding and historical flood levels. The results of the survey are then used to design a bespoke flood protection system for the particular property 12. Specifically, the variables can typically include: subsurface barrier wall 20 depth, barrier wall 16 construction and height, drain depth, dimensions and position relative to the barrier wall 14, pumping station (sump 30) capacity, as well as placement of sensors 102-106, described in further detail below.

The barrier wall 14 in the preferred embodiment is formed of four primary components. The buried footing 20 is in the form of a concrete foundation. The upstanding wall 16 preferably includes an anchor system of rebars and steel mesh, a composite construction panel comprising an insulated polystyrene core approximately 50mm width encased in a welded wire mesh either side, which connect to each other via braces shot through the core and welded in place. On the outside of the frame and skeleton structure, there is preferably a dry spray concrete, such as spraycrete, as a layer between 50-100mm thick completely encasing the construction panel and rebars.

The subsurface barrier wall 20 is laid down around the periphery of the zone 22 to be protected according to specifications determined during the site survey. The concrete used is preferably high density and waterproof, with a system of rebars and mesh reinforcements (not shown but which will be apparent to the skilled person from the teachings herein) set in place before the concrete is poured/sprayed. These are used to anchor the upstanding wall 16 to the foundations 20. The lower part of the rebars are preferably either Ό’ or ‘L’ shaped, providing strength against the lateral forces caused by rising water levels outside the barrier wall structure 14. Rebars are preferably set at pre-determ ined intervals along the line of the wall structure 14 and emerge vertically from the foundations 20 to a height just below the top of the barrier wall 14. Rebars are advantageously configured in a staggered sequence along the length of the wall 14, with each successive rebar emerging on either the front or back face of the wall. Construction panels are cut to pre-determ ined dimensions and lowered in position between the staggered rebars. A hydrostatic layer is preferably laid on the concrete beneath the panels to increase waterproofing, with a bitumen layer advantageously used in addition, where appropriate. Binding wire may be used to join the panel’s wire mesh to the rebars, creating a rigid construction ready for the concrete spray (spraycrete) layer. Apertures or gaps are left in the barrier 14 to allow removable waterproof panels or gates to be placed at access points, such as pedestrian gates and driveways. Once formed the wall 16 represents a strong, impermeable barrier preventing surface water reaching into the protected zone 22.

In the preferred embodiment, the drain system 32-34 includes one or more trenches of approximately 400mm (width) x 400mm (depth) excavated around the property inside the barrier wall 14, with 10mm pea shingle backfill and a porous membrane lining and perforated land drainage pipes. Dimensions are typically determined on the basis of the site survey. The or each trench is excavated to a suitable depth and width and typically will surround the property 12 but may in some cases only partially do so. A porous membrane is laid into the trench floor and sides to create a particle barrier while allowing the ingress of water into the trench. Perforated land drains are laid onto a bed of pea shingle at an inclination down to the sump 30 and then backfilled to the top of the trench. One end of the pipes 32-34 enters the sump 30 to allow waste water to be collected.

As ground water underneath the property 12 rises, the membrane and shingle allows the water to enter the perforated drains and from there flow down the incline into the sump 30. Surface water caused by heavy rainfall inside the barrier 14 can also enter the land drains from the top of the trench, soaking through the shingle to be collected and carried to the sump 30. The differential in pressure created by the water as it exits into the sump 30 ensures rapid draining of the trench.

In a standard installation the subsurface barrier 20 may typically have a depth of around 1.5 metres, while the drains 32-34 will be spaced around 1 metre from the subsurface barrier 20 and be at a depth of around 1.5 metres also or a little higher, that is closer to the ground surface.

In addition to having drains adjacent the perimeter barrier 20 there may be provided drains within the protected zone 22, for instance close to a building 22, as depicted with drain 32 in Figure 1. The drains 32, 34 are buried at a depth which is determined on the basis of the porosity of the soil and in some embodiments also on the expected amount of incoming water into the protected zone 22 from historical records. The intention of the drain system 32, 34 is to allow the removal of ground water from under the soil in the protected zone 22, whether this is ground water emanating from outside the protected zone, ground water within the protected zone, rain water coming into the protected zone or any combination of these. Initial site surveys can determine on the basis of the expected water ingress into the protected zone and soil porosity not only the size of the drains and their ideal drain angle but also their position relative to the perimeter wall 14 and depth to which they are buried. The aim is to ensure that the drains are able to remove sufficient volumes of water to maintain the water table below flooding levels, that is to no more than the level of the ground surface, or below ground surface, in order to prevent flooding in the protected zone 22 and water ingress into any building 12. The provision of subsurface drains will allow a reduction in the level of the water table 100. As illustrated in Figure 1, drainage of ground water within the protected zone 22 creates a curving water table between the drain system 32,34, the sump 30 and the buried barrier wall 20. It is the highest points of the water table which are relevant to the determination of the positioning of the drains 32-34 and the sump 30, as well as the depth of the buried barrier wall 20, these highest points being dependent upon the ability of water to soak through the soil, that is the porosity of the soil, and the speed of drainage provided by the drainage system 30-34. The curvature of the water table can be determined by determining the speed of flow of water through the soil, typically in litres per metre per second.

The system 10 shown in Figure 1 also includes a plurality of sensors 102-106, shown schematically in the Figure. A first sensor 102 is located in the sump 30 and is intended to determine whether the level of water in the sump 30 has reached a threshold requiring pumping of water out of the sump, to outside the protected zone 22. A second sensor 104 is located within the protected zone 22 and in practice is positioned within a sump which in one embodiment is a buried tube having an open or water permeable lower end, for instance provided with a porous mesh across its lower end. The sump tube may have a depth of 2 metres. Located at the bottom of the sump tube is a sensor probe 104 able to obtain a measure of the head or height of water within the tube and therefrom the state of impregnation of the ground. A third, optional, sensor 106 is disposed outside the barrier wall 14, that is outside the protected zone 22 and is arranged to detect the presence of ground water in order to give an early indication of possible flooding.

Further details of the sensors are given below and it is also to be understood that the system 10 is not limited to the provision of three sensors. In some embodiments there may be fewer while in other embodiments there may be more. In addition, there may be provided a plurality of each sensor type, disposed in different locations within and/or outside the protected zone 22. In its simplest form, the system 10 may have no sensors 102-104, in which case there may be a continuously operable pump within the sump 30, switchable only when there is no water in the sump. In other forms, there may be provided a water level sensor 102 in the sump 30, in other more sophisticated systems both a sump sensor 102 and a ground sensor 104. The optional outlying sensor 106 can be provided in what could be described as a complete solution.

The system 100 also includes a control unit, which is depicted schematically at 108, and may in practice be located within the building 12 so that it can be operated by a user, for example an inhabitant of the building 12 and so that the system 108 can provide feedback and warnings to the user.

The control unit 108 is coupled to the sensors 102-106 and also to the pumping unit provided within the sump 30. The control unit 108, in combination with the sensors 102-106 and the pumping unit are designed to optimise the control of water within the protected zone 22 and specifically to reduce unnecessary pumping of water in order maximise efficiency of the system 100, allowing natural water drainage when this is possible. The control unit 108 is also designed to warn users or inhabitants within the protected zone 22, and optionally a remote management station, of the risk of flooding so that protective measures can be taken, such as closing gates and other openings in the barrier wall 14. Further details of advantages and operation of the control system 108 are given below.

Figures 2 to 7 show examples of elements of the system 10 of preferred embodiments of the invention. The skilled person will appreciate that these are embodiments only and not restrictive of the teachings herein.

Referring first to Figure 2, this is a plan view showing a part of a protected zone 22, surrounded by a perimeter barrier 14 of the type disclosed in connection with the example of Figure 1 above. As can be seen, the perimeter barrier 14 has a shape and dimensions suitable for delimiting a desired perimeter zone around, in this example, a building 12. There may be provided one or more access points 102 through the barrier 14, for instance raisable or swingable panel gates. The building 12 includes, in this example, a utility or plant room 110 within which the control unit 108 is located. There is provided a buried electrical duct 120 leading to the sump 30 and in particular to the sensor located within the sump and to the draining pump. The duct 120 may typically have a diameter of 120 mm and be buried to a depth of around 500 mm, these being typical dimensions.

The sub-surface channels 32, 34 are located adjacent the perimeter barrier 14 and outside the perimeter of the building 12, in practice being usefully located also for collecting rain water and other water landing onto the ground in the protected zone 22. The channels 32, 34 are also positioned to collect sub-surface water from a rising water table or ground water coming from outside the perimeter barrier 14, by virtue of being open at their upper sides.

Figure 3 shows a cross-sectional view of an example of the perimeter wall 14 suitable for the embodiment of Figure 2 and other embodiments disclosed herein. The cross-section in Figure 3 shows only a part of the buried footing 20 of the barrier wall 14. In the example of Figure 3, the perimeter barrier 14 is chosen to have a height of around 800 mm and usefully includes buried ducts 122 for electrical wires to and from the control unit 108, with an optional electrical junction box also being buried in the wall 14.

On the outside of the perimeter wall 14, that is outside the protected zone 22, there is provided a small sump 130 at the foot of the barrier wall 14 and having, in this example, a depth of around 250 mm. Disposed within the sump 30 is a water sensor 106, described in further detail below. The sensor 106 includes a wire 126 coupling the sensor to the control unit 108. The sump 130 is typically protected from clogging in a manner which is known in the art, and preferably allows draining of water therein. There will typically be provision against the sump filling with debris and the skilled person will be fully aware of suitable elements for this. The sensor 106 is preferably of a type which will trigger only once a threshold head of water has been reached, for example 200 mm. Any suitable hydrostatic sensor could be used, for example.

Referring now to Figure 4, this shows the arrangement of sensors and cabling for the example system 100 shown in Figures 1 and 2. The skilled person will appreciate that Figure 4 shows an embodiment of the invention and that the number and positioning of the sensors may vary from one implementation to another.

In the example of Figure 4, there is provided an out-of-perimeter sensor 106 arranged as per Figure 3, a sensor 104 disposed within the protected perimeter 22 and in this example adjacent the perimeter wall 14, and a third sensor 102 disposed within the sump 30. Ducting 120-124 connects the sensors 102-106 to the control unit 108 located in the utility or plant room 110 of the building 108. These ducts 120-124 are preferably all buried below ground surface, as explained above.

The sensor 104 disposed within the protected zone 22 is preferably located within a small sump, having a depth, for example, of around 250 mm in this example but which could be up to 2000 mm deep or even deeper in dependence upon the nature of the zone 22. Sensor 104 can sense the amount of ground water present within the protected zone 22.

There may be provided other sensors similar to the sensors 102-106 shown in Figure 4 and in particular a plurality of sensors 106 disposed outside the perimeter wall 14 and/or a plurality of internal sensors 104 disposed in different locations within the protected zone 22. Provision of a plurality of each of the sensors 102,106 can give a better indication of the existence and location of any ground water either outside or inside the protected zone 22.

Figure 5 shows a plan view of the corner 140 of the perimeter barrier 14, as shown in Figures 2 and 4. As can be seen, the electrical ducting 122 extends through the concrete structure of the perimeter wall 14 to the sensor 106 and there may typically be provided an electrical junction box 150, preferably buried within the structure of the wall 14, for coupling electrical wires to and from the sensor 106 and the control unit 108.

Referring now to Figure 6, this shows a first embodiment of sump 30 of the system 10 taught herein. The sump 30 may have any suitable cross-sectional shape, though typically this may be square, rectangular or circular. The cross-sectional shape of the sump 30 is not relevant to the teachings herein. In the embodiments shown in the drawings, the sump 30 is circular cylindrical and has a cylindrical upstanding wall 152 preferably made of concrete, to which is attached a concrete base 154, which has a shape and size to conform with the outer perimeter of the upstanding wall 152. The base and upstanding wall are preferably secured to one another in substantially liquid-tight manner, although in some embodiments may allow for water drainage therethrough, useful in cases where water is able to drain naturally from within the protected zone 22, for instance as a result of dry ground conditions.

The top of the sump 30 is covered by, in this example, a concrete cover 156, although in other embodiments could be of other materials. In this example there is provided with an access 158 providing a manhole. The access 158 can usefully have brick walls, such that the entirety of the sump 30 can be buried below the surface of the ground 160, leaving access into the interior of the sump 30 through a manhole cover 162, typically made of metal.

In the example of Figure 6, the sump 30 is positioned adjacent the upstanding wall 14. Disposed within the sump 30 is a pump unit 170 to which are connected a lifting bale 172 and a lifting chain 174, the chain 174 extending towards the manhole cover 162 and preferably being hooked nearby, so that the pump unit 170 can be pulled up for maintenance or checking purposes. The pump unit 170 may have a single pump but preferably has a pair of pumps, which may be operated independently of one another or in unison.

Coupled to the pump unit 170 is an inlet tube 180 which has an open upper end 182 disposed at about the same height as inlet pipe 180 into the sump 130, the inlet pipe coupling to the buried channels 32, 34. The height of the pipe inlet 182 determines the maximum amount of water which can be stored within the sump 30 without forcing evacuation of water from within the sump 30. The skilled person will appreciate that the inlet pipe 180 could have different heights, as desired.

In practice, and as is described in further detail below, the inlet pipe 180 acts as a safety element which ensures that the pump 170 will operate when the sump 30 is filled with water, irrespective of what is detected by the sensors 102-106 of the system 10. In other words, even if no further water is detected within the protected zone 22, the pump unit 170 will operate if water within the sump 30 reaches above the height the upper end 182 of the inlet pipe 80.

The outlet of the pump unit 170 is coupled to an outlet pipe 190, which in this example has a closed upper end 192 which is secured to a bracket 194, itself secured to the concrete cover 156. In this example, the outlet pipe 190 includes a junction 200, to a discharge pipe 202, which terminates at an open end 204 beyond the perimeter of the wall 14 and therefore outside the protected zone, in this example for discharge into a drainage channel 210. The discharge pipe 202 is embedded within the structure of the wall 14 and preferably fixed thereto in fluid tight manner such that there is no leakage through the wall 14 at the location of the pipe 202.

Figure 7 shows a slightly modified version of the sump 30 of the system 10, compared to the embodiment shown in Figure 6. In the sketch of Figure 7, the concrete structure of the sump 30 is now shown. The inlet tube 184 from the buried channels 32, 34 is disposed lower within the sump 30 than the embodiment of Figure 6 and the pump inlet pipe 180 is closed and held by a suitable guide support element 220.

The outlet pipe from the pump unit 170 is blocked at its upper end 192, while the junction 200 feeds pumped fluid into the outlet pipe 204, which is coupled through a flexible tubing 206 buried within the ground 160 and exiting just at the top, exterior surface, of the wall 14, thereby pumping water from the sump 30 to the other side of the barrier wall 14 and outside the protected zone 22.

The skilled person will appreciate that the specific design of the sump 30 and the arrangement of the pump unit 170 and inlet and outlet pipes thereto is not critical to the teachings herein.

Referring now to Figure 8, this shows in very basic form the principal components of an example of control unit 108. The person skilled in the art will appreciate that a typical control unit 108 would include a variety of other components and elements for providing different functions, displays and warnings, which will all be readily apparent to a person skilled in the art. A control unit 108 will typically include a microprocessor 230, memory 232, a input/output controller 234 and a communications unit 235, all of which can be of a structure and design which will be familiar to the skilled person. The control unit 108 includes a series of inputs 236 for receiving signals from the various sensors 102-106, an output 238 for controlling the motor unit 170 and another input/output 240 for receiving user commands and for providing user data and warnings. The input/output may include a keypad, other control knobs and elements, a display and a visual or acoustic device. Again, these are well-known in the art and therefore not described in detail herein.

The control unit 108 can be disposed within the protected zone 22 and in the embodiments shown within the building 12, but equally could be disposed at a remote monitoring station outside the protected zone 22. It is envisaged that in most embodiments, the control unit 108 will also include communications unit 235 for communicating information to and from a central monitoring station 280, which can monitor operation of the system 10 and the status of the protected zone 22. The central monitoring station 280 may also communicate with a user, for instance over a standard telephone line or cellular telephone connection, and to a rapid response assistance service 280 when the risk of flooding within the protected zone is considered to exceed a threshold risk.

The structure of system 10 disclosed above and shown in the drawings can provide a complete multi-stage property level and area wide flood protection system having the following characteristics.

The preferred embodiments provide a system 10 which could be said to be formed of five distinct elements working together to provide flood protection. The five elements include: 1) a protective barrier wall 14 surrounding the property, designed to keep surface water away whilst allowing pedestrian and vehicle access through appropriate access ways; 2) a system of channels or drains 32, 34 within the protected area 22 for collecting ground water as it rises from below the property 12, feeding it into the sump 30 of the pumping station. The drainage system 32,34 can also absorb surface water from above caused by heavy rainfall; 3) a sump 30 and pumping station 170 designed to remove the drained water to outside the protected area 22. The pumping unit 170 preferably has dual pumps, which can be operated individually or together; 4) a local control system 102-108 which includes one or more hydrostatic sensors, one or more rain gauges and a control module that monitors water levels and activates the pump or pumps 170; and 5) a telemetry system 108 which monitors and manages water levels and pump station activity, sending alerts and alarms to designated recipients via SMS and email messages. The telemetry system can be incorporated into the control unit 108 and include a suitable transceiver unit 235 with the input/output unit 234.

The control unit 108 may in some cases simply monitor water and warn the user of impending flooding, allowing the user to close any barriers in the wall 14 to close off the zone 22. The control unit 108 will make use of the sensors 102-108 for this purpose. The pumping station 170 will pump water out of the sump 30 when the sensor 102 detects water above the predetermined threshold level or the water level reached the top of the inlet pipe 180. In other embodiments, the control unit 108 can make use of the signals form the rain water sensor 104 to determine the rate of collection of water and to alter the rate of pumping of the pump unit 170 to ensure that water is removed from the protected zone 22 at a sufficient rate. Similarly, the control unit 108 may allow rain water to drain naturally into the ground when the sensor 104 does not sense water in the small sump in which it is located indicative of the ground being relatively dry and therefore able to absorb rainwater. The control unit 108 is also able to issue a warning when it is determined from the signals from the outside sensor or sensors 106 that flooding is occurring outside the protected zone 22, that is outside the barrier 14. The warning can be sent to the user and to the remote monitoring station 280, in order to the access points in the wall 14 to be closed off. It is to be appreciated that the access barriers could be automatically operated in some embodiments for instance by motors linked to the control unit 108. As a result, the system 100 provides comprehensive monitoring and management of the protected zone and protection of the zone 22.

The sump and pumping station 30 170 includes three primary elements: input ports 184 into the sump 30 from the land drains 32-34, one or dual pumps 170 to evacuate the collected water and a rising main pipe 190 to expel the collected water to outside the barrier wall 14.

The size of the sump 30, pump 170 capacity and rising main pipe 190 dimensions are determined for each individual zone 22 to be protected. In practice, a sump pit is excavated in a specified position inside the barrier wall 14. Typically this will be 2 metres deep and 2.5 metres diameter. The sump 30 is lowered into position and anchored with poured concrete. Ports are bored into the sump 30 for the input 184 from the land drains which are secured in place with seals. A port for the rising main 190 is also bored and the pump or pumps 170 and pipework 180/190 fitted. The sump pit is then backfilled with shingle as specified.

As the water level rises, the sump sensor 102 activates the system and the pumps drain the water in the sump 30 back to a pre-determined mean level, preferably outside the barrier wall 14. This process repeats for as long as water rises to a depth above a set level.

The local control system 108 has three primary elements: a hydrostatic sensor 102 placed at the bottom of the sump 30, a series of remote sensors 104, 106 is placed around the protected area 22, both inside and outside the barrier wall 14, a digital control module 108 is responsible for controlling the pump or pumps 170 fed by the sensor inputs 236.

The hydrostatic sensor 102 is preferably fitted to the bottom of the sump 30 and connected to the control module 108. The sensor 102 is calibrated to read 0 bar with the sump 30 empty. As the water level rises in the sump 30, the increase in pressure is relayed to the control module 108 which expresses the change in units (for instance millimetres) depth of water in the sump 30. Once a set threshold is passed, the module 108 initiates the pumping station 170 which returns the water to the mean level. If the ingress of water is sufficiently rapid, a further threshold is crossed which activates both pumps simultaneously, increasing the water flow to the rising main. The threshold can be determined by the speed of replenishment of the sump 30, the detected level of ground water by the senor 104, the level of water outside the protected zone 22 or any combination of these. The control system 108, either internally or by external control from a user or the remote management station 280 can also change the threshold level at which pumping commences to evacuate water from the sump 30, which can also be useful when it is determined that there are high volumes of incoming water.

For instance, the control unit 108 and/or the remote management station 280 could be designed to control the pumping unit 170 to pump continuously when it is determined that there is a large volume of incoming flood water. The provision of dual pumps can also provide a backup pump facility in the event of failure of one of the two pumps.

The remote sensors 102, 104, placed both inside and outside the barrier wall 14, monitor water levels within and outside the protected area 22. They are connected to the control module 108, the latter being set to send alarms which in turn can alert designated recipients of the need to close removable barriers in the wall, or other actions necessary to protect the property. Specifically, the system 10 is able to detect the onset of flooding, allowing users to take preventative measures before flooding actually occurs.

The rain gauge sensor 104 provides information on local precipitation and this data can be used with that from the remote sensor 106, providing additional warning of impending flood conditions.

The preferred telemetry system includes the following elements: a communications module and transceiver 234, 235 housed in the main control unit 108, a cellular telephone or satellite telephone communications facility for transmitting and receiving data, a remote management station 250 (see Figure 8) for monitoring and controlling the system 10. The communications module 234-235 is connected to the system processor 230 within the main control unit 108. A mobile telephone sim card may be provided and configured to allow the exchange of data between designated recipients and also to dedicated remote management station 250.

As thresholds are exceeded and pumps 170 activated, data is fed to the remote management station 250 which can be monitored and interacted with from any internet enabled device. The remote station 250 can configure the local control system 108 to change the pumping parameters, for instance when it is detected that there is a high volume of water, as well as to send alerts to designated recipients. Furthermore, the transceiver module 235 in the control unit 108 can be configured to send alerts directly to designated persons, for example by a SMS alert.

The system 10 disclosed herein can therefore provide: a) a barrier 14 built around a property 12 or other area to be protected, which prevents surface water entering the protected area 22 whilst allowing access for pedestrians and vehicles; b) a drainage system 32-34 that removes ground water from below and surface water from above the property; c) a pumping system 170 that evacuates collected water to outside the barrier 14; d) a local control system 108 that operates the pumping station 30; e) a telemetry system that allows remote management of the system and provides SMS and email alerts to designated recipients.

All optional and preferred features and modifications of the described embodiments and dependent claims are usable in all aspects of the invention taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.

The disclosure in the abstract accompanying this application is incorporated herein by reference.

Claims

1. A flood management system for protecting a zone from flood water, including: a perimeter barrier disposed around a protected zone, the barrier including an upstanding wall for blocking surface water ingress into the protected zone and a subsurface barrier wall; a drainage system within the protected zone including at least one drainage unit disposed subsurface and adjacent the subsurface barrier wall; and a sump to which the drainage system is fluidically coupled for collecting water from the drainage system.

2. A flood management system according to claim 1, wherein the at least one drainage unit is a drainage channel.

3. A flood management system according to claim 1 or 2, wherein the at least one drainage unit is spaced from the subsurface barrier wall.

4. A flood management system according to claim 3, wherein the at least one drainage unit is spaced from the subsurface barrier wall by a distance permitting flow of ground water passing under the subsurface barrier wall into the channel or channels.

5. A flood management system according to claim 4, including at least one drainage unit spaced around one metre from the subsurface barrier wall.

6. A flood management system according to claim 5 or 6, including at least one drainage unit spaced by more than one metre from the subsurface barrier wall.

7. A flood management system according to any preceding claim, wherein the or at least one drainage unit is open at a top thereof at least adjacent the sump.

8. A flood management system according to claim 7, wherein the or at least one drainage unit is connected to the sump at a depth lower than a threshold water level.

9. A flood management system according to claim 8, wherein the threshold water level is an acceptable water table level in the protected zone.

10. A flood management system according to any preceding claim, including a pumping unit disposed to pump water from the sump to outside the protected zone.

11. A flood management system according to claim 10, wherein the pumping unit includes one or a plurality of pumps.

12. A flood management system according to claim 11, wherein both pumps are activated when water flow is determined to exceed a threshold rate.

13. A flood management system according to claim 10, 11 or 12, including a water level sensor disposed to measure water level in the sump.

14. A flood management system according to claim 13, wherein the water level sensor is a hydrostatic sensor.

15. A flood management system according to any preceding claim, including one or more sensors for measuring surface or ground water inside the protected zone.

16. A flood management system according to any preceding claim, including one or more sensors for measuring surface or ground water outside the protected zone.

17. A flood management system according to claim 15 or 16, including a control unit coupled to the sensor or sensors.

18. A flood management system according to claim 17, wherein the control unit is disposed in the protected zone.

19. A flood management system according to claim 17 or 18, wherein the control unit includes a telemetry unit operable to monitor and manage water levels and pump unit activity.

20. A flood management system according to claim 19, wherein the telemetry system includes a communications unit operable to send flood related alerts and/or alarms.

21. A flood management system according to any preceding claim, including a remote management station communicatively coupled to the or a control unit.

22. A method of preventing flooding to a protected zone including the steps of: forming a perimeter barrier around a zone to be protected, the barrier including an upstanding wall for blocking surface water ingress into the protected zone and a subsurface barrier wall; forming a drainage system within the protected zone, the drainage system including at least one drainage unit disposed subsurface and adjacent the subsurface barrier wall; disposing a sump to which the drainage system is fluidically coupled for collecting water from the drainage system.

23. A method according to claim 22, including the step of determining water porosity of soil where the perimeter barrier is to be formed and determining the depth of the subsurface barrier wall on the basis of the determined soil porosity.

24. A method according to claim 23, wherein the subsurface barrier wall is formed to have a greater depth in porous soil and a lesser depth in less porous soil.

25. A method according to claim 22, 23 or 24, including the step of spacing the at least one drainage unit from the perimeter barrier.

26. A method according to claim 26, including the step of determining the spacing of the at least one drainage unit on the basis of the porosity of the soil.

27. A method according to claim 25 or 26, including the step of determining the depth at which the at least one drainage unit is formed on the basis of determined soil porosity.

28. A method according to claim 25, 26 or 27, including the step of determining the size of the at least one drainage unit on the basis of determined or estimated water flow.

29. A method according to any one of claims 22 to 28, including the step of providing a pumping unit in the protected zone and fluidically coupling the pumping unit to the sump system, the pumping station including at least one outlet extending beyond the barrier to remove collected water out of the protected zone.

30. A method according to claim 29, including the step of providing a water sensor to measure water level in the sump.

31. A method according to any one of claims 22 to 30, including the step of disposing in the protected zone one or more water sensors for measuring surface or ground water within the protected zone.

32. A method according to any one of claims 22 to 31, including the step of disposing outside the protected zone one or more water sensors for measuring surface or ground water outside the protected zone.

33. A method according to any one of claims 22 to 32, including the step of providing a control unit.

34. A method according to claim 33, including the step providing a remote management station able to communicate with the or a control unit.