DK181022B1

DK181022B1 - Dike System and Method for Preventing Flooding of an area provided behind a dike system

Info

Publication number: DK181022B1
Application number: DKPA202100469A
Authority: DK
Inventors: Gramkow Asger
Original assignee: Hiddendyke Aps
Priority date: 2021-05-06
Filing date: 2021-05-06
Publication date: 2022-09-29
Also published as: DK202100469A1

Abstract

A dike system (2) comprising a watertight membrane (4) defining an inner space (30) configured to receive and contain a liquid (20) and hereby increase volume of the inner space (30) is disclosed. The inner space (30) of the dike system (2) is filled with both a liquid and a gas (50), wherein the volume of gas constitutes between 3 and 30 o of the volume of the inner space (30).

Description

DK 181022 B1 1 Dike System and Method for Preventing Flooding of an area pro- vided behind a dike system Field of invention The present invention relates to a dike system and a method for pre- venting flooding by applying a dike system. Prior art The incidence of flood disasters is increasing at a devastating rate. In terms of incidence and economic losses, floods account for around a third of all natural disasters as well as half of the fatalities. Efforts to curb climate change may reduce the frequency of flooding but another approach would be to step up methods of flood protection and minimi- sation. One very effective, but simple in principle, method for flood pro- tection is the construction of dikes, artificial water channels that prevent runoffs from bursting floodplains. One problem is that the majority of dikes in Europe are old (up to 150 years old) and do not fulfil present safety standards.

Addressing this problem, the EU-funded ‘Land protection by improve- ment of dike Addressing this problem, the EU-funded ‘Land protection by improvement of dike construction’ (Prodicon) project aimed to de- velop a universal dike repair technology that can be applied on all types of dikes in different states of disrepair. Existing dike rehabilitation tech- niques are often quite expensive with a limited field of application. Pro- ject researchers tackled the problem from two different angles - by preparing a new material as well as a means by which this can be in- jected and incorporated into the dike structure. A major advantage of the new technique is that the material can be successfully applied to wetted and softened dikes using conventional excavation machinery with modular exchangeable equipment units.

DK 181022 B1 2 The existing dikes too must keep up with the times.

But dikes can no longer be reinforced simply by raising them again and again: height in- creases are not only subject to spatial and physical constraints, but also to public opposition.

For instance, if historic dike houses would have to be demolished in order to raise the height of a dike, it is worth consid- ering alternatives.

Different type of dike systems: sea dikes, river dikes, polder dikes, lake dikes, canal dikes, defence line dikes, dams and storm surge barriers.

In addition to being cost-effective, new infrastructure must minimize environmental impacts and be adaptable to changing climate conditions.

Flood protection systems for damming up against a rising water level are widely used and well-known.

These systems typically either have to be installed when the risk for flooding approaches or are permanently installed above ground level.

The systems that have to be installed in case of a flooding condition risk are often time consuming to install and difficult to be installed because installation staff are busy and thus difficult to procure when the systems have to be installed.

On the other hand, the permanently installed systems take up a lot of space and are often also accused of being associated with visual effects such as disfigurement of the landscape.

CA2204700A1 discloses a portable dike system formed from dike sec- tions, wherein each section includes an inflatable bladder and an an- choring flap affixed to a lower portion of the bladder and extending along the ground on the floodwater side of the bladder, to anchor the dike section to the ground.

The bladder is inflated to the required height.

This solution, however, needs to be monitored by staff in order

DK 181022 B1 3 to make sure that the dike sections are well-functioning and no dike section is leaking. Moreover, impact from water (e.g. incoming waves) can damage the dike system. Accordingly, it would be desirable to have an improved dike system which can resist impact from water such as incoming waves. Moreover, it would be desirable to have an improved dike system in which the need for monitoring staff can be eliminated.

It is an object of the invention to provide a dike system which can resist impact from water such as incoming waves. It is also an object of the invention to provide a dike system in which the need for monitoring staff can be eliminated. It is furthermore an object of the invention to provide a method for pre- venting flooding of an area provided behind a dike system, wherein the method provides as solution that can resist impact from water such as incoming waves and does not need to be monitored by staff in order to make sure that no dike section is leaking. Summary of the invention The object of the present invention can be achieved by a dike system as defined in claim 1 and a method as defined in claim 10. Preferred em- bodiments are defined in the dependent subclaims, explained in the fol- lowing description and illustrated in the accompanying drawings. The dike system according to the invention is a dike system comprising a watertight membrane defining an inner space configured to receive and contain a liquid and hereby increase the volume of the inner space, wherein the inner space is filled with water as well as gas, wherein the

DK 181022 B1 4 volume of the gas constitutes between 3 and 30 % of the volume of the inner space. Hereby, it is possible to provide a dike system which can resist impact from water such as incoming waves. The air-filled portion of the inner space represents a resilient portion that is configured to allow the membrane to be exerted to impacts from incoming waves without dam- aging or moving the membrane. Accordingly, filling a controlled amount of air into the inner space solves the technical problem of the prior art.

Namely, that the membrane can be damaged and/or moved when in- coming waves hit the membrane.

By the term “water” is meant a water containing liquid. Accordingly, water may be drinking water, sea water, rain water or water from a pond.

By the term “gas” is meant any suitable type of gas including atmos- pheric air.

In a preferred embodiment, the gas is atmospheric air.

In one embodiment, the system comprises a liquid and gas assembly configured to guide water and gas into the inner space.

In one embodiment, the system comprises a plurality of inlet assem- blies distributed along the length of the membrane, wherein each inlet assembly is configured to guide water and gas into the inner space.

In one embodiment, the dike system comprises a detection unit config- ured to detect leakage from the watertight membrane.

Hereby, it is possible to provide a dike system in which the need for

DK 181022 B1 monitoring staff can be eliminated. The detection unit will detect any leakage from the watertight mem- brane. 5 In one embodiment, the dike system comprises an alerting device con- figured to generate a visual alarm. In one embodiment, the dike system comprises an alerting device con- figured to generate an audible alarm. In one embodiment, the dike system comprises an alerting device con- figured to generate an alarm in case of a leakage and in the event of an alarm contact an external device (e.g. a central monitoring station) or a phone, computer or another device of one or more persons. Operators, hereby, any person that sees or hears the signal can take appropriate action, such as contacting service personnel, notifying police, or dis- patching private security forces. The alarm may be transmitted via ded- icated alarm circuits, telephone lines, or the internet.

Hereby, it is possible to provide a simple and efficient dike system that can be operated and build in an easy manner. A typical prior art dike system of 1.5 m height costs approximately EUR 470 per meter. The price for a system according to the invention will be approximately EUR 435 per meter. The dike system does not require installation staff once it has been in- stalled. Moreover, the dike system does not take up a lot of space and more importantly it is hidden and thus is not associated with visual ef- fects such as disfigurement of the landscape. The dike system comprising a watertight membrane defining an inner

DK 181022 B1 6 space configured to receive and contain a liquid.

The membrane is pref- erably made of a flexible material that is capable of being brought into a first configuration in which the membrane is empty or close to being empty and into another configuration, in which the volume of the inner space is increased (when water has been filled into the inner space). The membrane is made in a material allowing the membrane to be filled and emptied a large number (e.g. more than 10) of times.

Hereby, the volume of the inner space can be increased and reduced without dam- aging the membrane.

In a preferred embodiment, the detection unit is configured to detect leakage from the watertight membrane, when the watertight membrane contains less than 10% of the liquid that the watertight membrane is designed to contain.

In one embodiment, the detection unit is a pressure sensor arranged at the bottom area of the watertight membrane.

Accordingly, the pressure sensor is arranged to detect when the pressure of liquid in the water- tight membrane changes.

If the watertight membrane contains less than 10% of the liquid that the watertight membrane is designed to contain, and the watertight membrane is leaking, the pressure sensor will detect a gradually decreasing pressure of liquid in the watertight membrane.

Accordingly, the pressure sensor is configured to detect leakage from the watertight membrane.

By having a pressure sensor arranged in the membrane, it is possible to leave a small quantity of water in the membrane and use the pressure sensor as a leakage sensor (in case of leakage, the pressure will drop to zero). In one embodiment, the pressure source is connected to a water supply

DK 181022 B1 7 line or a water reservoir (e.g. a lake, a well or a river). In one embodiment, the dike system comprises a first inlet connected to a pressure source.

In one embodiment, the dike system comprises a second inlet connect- ed to a second pressure source. In one embodiment, the detection unit is a flow sensor arranged at the bottom area of the watertight membrane. Accordingly, the flow sensor is arranged to detect when the flow of liquid in the watertight mem- brane changes. If the watertight membrane contains less than 10% of the liquid that the watertight membrane is designed to contain, and the watertight membrane is leaking, the flow sensor will detect a gradually decreasing flow of liquid in the watertight membrane. Accordingly, the flow sensor is configured to detect leakage from the watertight mem- brane.

In one embodiment, the membrane is at least partly covered with a covering material.

The covering material may be soil, sand, geonet or a liner by way of example.

In one embodiment, the membrane is completely covered with soil, sand, geonet (geotextile) or another substance like a liner. In one em- bodiment according to the invention the membrane is completely or al- most completely covered with soil or sand.

By the term soil is meant either: a) a mixture of minerals and/or stones and/or organic matter. Accordingly, soil may include any suitable com- bination of objects suitable of being arranged over the membrane to

DK 181022 B1 8 cover it. By the term liner is meant any suitable type of liner. In one embodi- ment, the liner is a polypropylen liner. In one embodiment, the liner is a heavy duty polypropylen liner. In one embodiment, the liner is a polyes- ter liner. In one embodiment, the liner is a heavy-duty polyester liner. In one embodiment, the liner is made in another suitable thermoplastic material.

In one embodiment, the system comprises a top layer arranged to cov- er the liner. In one embodiment, the top layer is made of artificial grass.

By the term sand is meant any of the following: a) gravel or loose granular material that results from the disintegration of rocks, consists of particles smaller than gravel; b) small structures (e.g. basically ball- shaped) made of stone, metal, glass, rubber, plastic or a ceramic mate- rial.

In one embodiment, the membrane has a length and a width and is shaped as an elongated body portion, wherein the length is larger than three times the width of the membrane. Hereby, it is possible to in- crease the height of the membrane to a large extent by using a small quantity of water.

In one embodiment, the membrane is shaped as an elongated body portion, wherein the length is larger than five times the width of the membrane.

In one embodiment, the membrane is shaped as an elongated body portion, wherein the length is larger than ten times the width of the membrane.

DK 181022 B1 9 In one embodiment, the membrane is shaped as an elongated body portion, wherein the length is larger than fifteen times the width of the membrane.

In one embodiment, the membrane is shaped as an elongated body portion, wherein the length is larger than twenty times the width of the membrane.

In one embodiment, the height of the membrane (when the membrane is filled with water) corresponds to the width of the membrane (when the membrane is filled with water).

In one embodiment, the dike system comprises first membrane and a second membrane arranged on the top of the first membrane. Hereby, it is possible to increase the height of the dike system.

It may be an advantage to deliver liquid to both membranes by using a single source (suitable for providing liquid and/or air to both mem- branes).

In one embodiment, the dike system is filled with a liquid (e.g. water) as well as a gas (e.g. atmospheric air).

In one embodiment, at least 5% of the volume of the inner space is air- filled.

In one embodiment, at least 10% of the volume of the inner space is air-filled.

In one embodiment, the membrane has a length and a width, wherein the membrane is shaped as an elongated body portion, wherein the

DK 181022 B1 10 length is larger than three times the width of the membrane. In one embodiment, the dike system comprises: a) a pressure source or b) an inlet connection structure configured to be brought into fluid communication with a pressure source. Hereby, filling of the inner space can be accomplished in a fast and effi- cient manner. By having several inlets each being connected to a pressure source, it is possible to fill the membrane in a faster manner. In one embodiment, the dike system comprises a first outlet connected to a drainage structure (e.g. a well, a river or a lake).

In one embodiment, the dike system comprises a second outlet con- nected to a drainage structure (e.g. a well, a river or a lake). By having several outlets, each being connected to a drainage struc- ture, it is possible to empty the membrane in a faster manner and to distribute the water inside the membrane to several areas, if required. In one embodiment, the dike system comprises an outlet connection structure configured to be brought into fluid communication with a re- ceiving unit shaped and arranged to receive liquid from the dike sys- tem. In one embodiment, the dike system comprises an outlet connection structure adapted to be connected to a well.

In one embodiment, the dike system comprises a well.

DK 181022 B1 11 In one embodiment, the dike system comprises a plurality of attach- ment members arranged to attach the membrane to the ground. Hereby, it is possible to control the motion of the membrane when be- ing filled with water and emptied again. By knowing the movement pat- terns of the membrane, it is possible to predict and hereby minimise the wear and the risk for damage.

In one embodiment, the attachment members are shaped as spikes, shaped to attach the membrane to the ground.

In one embodiment, the attachment members are equipped with a hook or hole on the top end of the spike.

The attachment members may be pushed or driven into the ground for holding the membrane to the ground, either directly by attaching to an attachment structure of the membrane.

In one embodiment, the dike system comprises a mesh structure ar- ranged between the surface profile and the membrane. Hereby, the mesh structure can prevent the soil from being wrested from the top portion of the dike. The mesh structure will allow vegetation to easier take root hereby creating a top layer that can withstand the forces ap- plied to the top layer when water is filled into the inner space of the membrane.

The mesh structure may be a geotextile. In one embodiment, the mesh structure may be a permeable fabric configured to be used in association with soil. It may be an advantage that the mesh structure is made from polypropylene or polyester or an- other suitable thermoplastic material.

DK 181022 B1 12 In one embodiment, the mesh structure extends parallel to the surface profile, when the membrane is empty. In one embodiment, the mesh structure extends parallel to the mem- brane when the membrane is empty. In one embodiment, the dike system comprises a ditch arranged in a lower level than the level in which the membrane is arranged.

In one embodiment, the membrane is arranged in such a manner that it extends parallel to an arced waterline. Hereby, the membrane can pro- vide the most efficient protection against flooding.

In one embodiment, the dike system comprises: a) a first inclined side being inclined towards an area in which water flood is expected and b) a second inclined side being inclined away from the area, wherein the angle between the first inclined side and the second in- clined side is in the range 90-150 degrees. In one embodiment, the angle between the first inclined side and the second inclined side is in the range 95-145 degrees.

In one embodiment, the angle between the first inclined side and the second inclined side is in the range 110-140 degrees. In one embodiment, the angle between the first inclined side and the second inclined side is in the range 120-135 degrees.

In one embodiment, the dike system comprises a mesh structure that extends along the entire width of the membrane both over and under

DK 181022 B1 13 the membrane. In one embodiment, the dike system comprises a liner that extends along the entire width of the membrane both over and under the mem- brane. In one embodiment, the dike system comprises a mesh structure and a line that extend along the entire width of the membrane both over and under the membrane.

Accordingly, the mesh structure and/or the line support and stabilize the membrane in its inflated configuration. The method according to the invention is a method for preventing flood- ing of an area provided behind a dike system, wherein the method comprises the step of: a) arranging on the ground a watertight membrane defining an inner space configured to receive and contain a liquid and hereby increase volume of the inner space and b) filling a liquid into the inner space to increase the volume of the inner space and hereby increase the vertical position of the top portion of the membrane and any soil or sand covering the membrane, wherein the membrane is shaped as an elongated body portion, wherein the method comprises the step of filling gas into the inner space of the membrane, wherein the volume of gas constitutes between 3 and 30 % of the volume of the inner space. Hereby, the method makes it possible to provide a dike system which can resist impact from water such as incoming waves. The air-filled por- tion of the inner space represents a resilient portion that is configured to allow the membrane to be exerted to impacts from incoming waves without damaging or moving the membrane.

DK 181022 B1 14 In one embodiment, the method comprises the step of detecting if the watertight membrane is leaking.

Hereby, it is possible to provide a method for preventing flooding of an area provided behind a dike system, wherein the method does not need to be monitored by staff in order to make sure that no dike section is leaking.

The term “on the ground” includes: directly on the ground or in a groove in the ground. In one embodiment, the method comprises the step of arranging a mesh structure between the surface profile of the dike system and the membrane. Hereby, it is possible to protect the vegetation on the dike system when the volume of the inner space is increase (when water is filled into the membrane). In one embodiment, the method comprises the step of: a) digging a trench; b) arranging the membrane in the trench and Cc) filling soil and sand on the top of the membrane. It may be an advantage to arrange the membrane in such a manner that the lower portion of the membrane extends horizontally. This can be achieved by digging a trench that extends horizontally. In one embodiment, the step of detecting if the watertight membrane is leaking is carried out by using a pressure sensor arranged in the water- tight membrane. In one embodiment, the step of detecting if the watertight membrane is

DK 181022 B1 15 leaking is carried out by using a flow sensor arranged in the watertight membrane.

In one embodiment, the method comprises the step of arranging the membrane in a position, in which the membrane is at least partly cov- ered with soil or sand or a liner.

Hereby, the membrane is hidden when not in use.

In one embodiment, the method comprises the step of attaching the membrane to the ground by using a plurality of spike-like attachment members.

Hereby, attachment of the membrane can be done in a sim- ple, efficient and reliable manner.

In one embodiment, the method comprises the step of arranging on the ground a first membrane and arranging a second membrane on the top of the first membrane.

Hereby, the height of the dike can be increased.

Description of the Drawings The invention will become more fully understood from the detailed de- scription given herein below.

The accompanying drawings are given by way of illustration only, and thus, they are not limitative of the present invention.

In the accompanying drawings: Fig. 1 shows a schematic cross-sectional view of a dike system according to the invention in a configuration, in which the membrane is empty; Fig. 2 shows a view of the dike system shown in Fig. 1 in a con- figuration, in which the membrane is filled; Fig. 3 shows a schematic cross-sectional view of another dike system according to the invention in a configuration, in which the membrane is empty; Fig. 4 shows a view of the dike system shown in Fig. 3 in a con- figuration, in which the membrane is filled;

DK 181022 B1 16 Fig. 5 shows a schematic cross-sectional view of another dike system according to the invention in a configuration, in which the membrane is empty; Fig. 6 shows a view of the dike system shown in Fig. 5 in a con- figuration, in which the membrane is filled; Fig. 7 shows a schematic top view of a dike system according to the invention; Fig. 8 shows a perspective view of a dike system according to the invention arranged along a straight coastline; Fig. 9 shows a perspective view of a dike system according to the invention arranged along an arced coastline; Fig. 10 shows a schematic cross-sectional view of a dike system according to the invention in a configuration, in which the membrane is empty; Fig. 11 shows a view of the dike system shown in Fig. 10 in a con- figuration, in which the membrane is filled; Fig. 12 shows a schematic view of a membrane of a dike system according to the invention; Fig. 13 shows a schematic view of a first membrane and a second membrane of a dike system according to the invention; Fig. 14 shows a schematic view of a membrane of a dike system according to the invention; Fig. 15 shows a schematic cross-sectional view of a dike system according to the invention in a configuration, in which the membrane is empty and Fig. 16 shows a view of the dike system shown in Fig. 15 in a con- figuration, in which the membrane is filled.

Detailed description of the invention Referring now in detail to the drawings for the purpose of illustrating preferred embodiments of the present invention, a dike system 2 of the present invention is illustrated in Fig. 1.

DK 181022 B1 17 Fig. 1 illustrates a schematic cross-sectional view of a dike system 2 according to the invention, whereas Fig. 2 illustrates a view of the dike system 2 shown in Fig. 1 in a configuration, in which the membrane 4 is filled with a fluid 20 (being water 24) and air 50.

The dike system 2 comprises a watertight membrane 4 comprising an inner space 30 configured to receive a liquid such as water. The mem- brane 4 is covered with soil or sand 6. In Fig. 1, the membrane 4 in a configuration, in which the membrane 4 comprises only a small quantity of liquid. Accordingly, the membrane 4 is not completely empty. Since the membrane 4 is at least partly covered with soil or sand 6. The soil or sand 6 is vertically displaced so that the upper portion of the dike system 2 is arranged in a higher level when the volume of the inner space 30 has increased. Hereby, the dike system 2 is capable of pro- tecting a low-ground area arranged behind the dike system 2 from be- ing flooded. The membrane 4 defines an inner space 30 configured to receive and contain a liquid 20 such as water 24 as well as atmospheric air 50 and hereby increase volume of the inner space 30. Hereby, the cross- sectional area of the membrane 4 changes from being basically flat to being basically drop shaped. The height Hi of the membrane 4 in the configuration shown in Fig. 2 (in which the volume of the inner space 30 has been increased) is indicated. It can be seen that the height Hi of the membrane 4 basically corresponds to the width Wj. The membrane 4 has a length (see Fig. 7) and a width W; and is shaped as an elongated body portion, wherein the length is larger than the width W; of the membrane 4. In order to make a practical solution, the length is larger than three times the width Wi of the membrane 4. Typically, the length is larger than ten times the width Wi of the mem-

DK 181022 B1 18 brane 4. In order to control the membrane 4, it may be an advantage to fix the membrane to the surrounding ground 16. This may be done like illus- trated in Fig. 1 and Fig. 2, where a spike-like attachment member 12 is used to attach an attachment structure of the membrane 4 to the ground 16. Hereby, this part of the membrane 4 will be fixed to the ground 16, whereas the opposite end portion of the membrane is free to move vertically upon increasing the volume of the inner space 30.

The surface profile 14 of the dike system 2 will typically be overgrown e.g. by grass or another vegetation.

A detection unit 25 is placed in the bottom area of the membrane 4.

The detection unit 25 may be a pressure sensor arranged and config- ured to detect the pressure of the liquid in the membrane 4. The detec- tion unit 25 may alternatively be a flow sensor arranged and configured to detect the flow of the liquid in the membrane 4.

Accordingly, the detection unit 25 is suitable of detecting if the mem- brane 4 is leaking. The air 50 inside the air-filled portion of the inner space of the membrane 4 is compressible. Accordingly, the air 50 func- tion as a resilient member (like a spring) that can be compressed when a force is exerted to the membrane 4 (e.g. from an incoming wave).

Fig. 3 illustrates a schematic cross-sectional view of another dike sys- tem 2 according to the invention in a configuration, in which the mem- brane 4 is almost empty, whereas Fig. 4 illustrates a view of the dike system shown in Fig. 3 in a configuration, in which the membrane 4 is filled. The dike system 2 basically corresponds to the one shown in Fig. 1 and Fig. 2. The surface profile 14 of the dike system 2, however, is basically flat, whereas the surface profile 14 of the dike system 2 shown

DK 181022 B1 19 in Fig. 1 comprises an elevation that protrudes from the surrounding structure. In Fig. 3, it can be seen that the dike system 2 comprises a mesh struc- ture 8 that is arranged between the surface profile 14 and the mem- brane 4. The mesh structure 8 extends parallel to the membrane 4 (when the membrane is empty as shown in Fig. 3). Moreover, it can be seen that the membrane 4 comprises a first side portion 18 and a sec- ond side portion 18’. The side portions 18, 18’ constitute the areas, in which the top portion and the bottom portion of the membrane 4 are connected. In one embodiment, a reinforcement structure is integrated in the first side portion 18 in order to provide mechanical strength to the first side portion 18. Hereby, it is possible to avoid that the side portion 18 is damaged when the membrane 4 is repeatedly filled and emptied. It may be an advantage that the reinforcement structure extends along the entire length of the membrane 4 in order to support the first side portion 18 along its entire length.

In Fig. 4 it can be seen that the membrane 4 is drop shaped when the inner space of the membrane 4 is filled with water 24 as well as gas 50. The mesh structure 8 is flexible and configured to support the soil or sand and the vegetation thereon during the deformation that occurs when the inner space of the membrane 4 is filled with water 24 and gas 50 (e.g. atmospheric air). A detecting unit 25 is arranged at the bottom portion of the membrane

4. The detecting unit 25 is arranged and configured to detect any leak- age from the membrane 4. The detecting unit 25 may be designed as a pressure sensor or as a flow sensor. In one embodiment, the detecting unit 25 can be omitted.

DK 181022 B1 20 Fig. 5 illustrates a schematic cross-sectional view of another dike sys- tem 2 according to the invention in a configuration, in which the mem- brane 4 is almost empty. Fig. 6 illustrates a cross-sectional view of the dike system 2 shown in Fig. 5 in a configuration, in which the mem- brane 4 is filled with water 20. Fig. 3 is a close-up view of the dike sys- tem 2 shown in Fig. 5, whereas Fig. 4 is a close-up view of the dike sys- tem 2 shown in Fig. 6.

The dike system 2 comprises a membrane 4 that is flat and horizontally arranged when no or only a small quantity of water is filled into the membrane 4. When a liquid 20 (e.g. water 24) as well as gas 50 is filled into the membrane 4, however, the membrane 4 has a drop shaped cross-sectional area. It can be seen that the dike system 2 comprises a flat top portion 38 extending between: a) a first inclined side 32 being inclined towards an area 36 in which water flood is expected and b) a second inclined side 34 being inclined away from the area 36.

The angle a between the first inclined side 32 and the second inclined side 34 is approximately 130 degrees.

The area 36 referred to is arranged next to a first level 40 provided at the foot of the first inclined side 32. The vertical distance Hz between the first level 40 and the level of the top portion 38 is indicated in Fig.

5. It can be seen that the vertical distance Hz between the first level 40 and the level of the top portion 38 in Fig. 6 is larger because the mem- brane 4 has been filled with a liquid 20 (e.g. water 24. The relationship between the indicated heights Hi, Hz and Hs is given by the following equation: (1) H, =H, +H,

DK 181022 B1 21 It can be seen that the width W; of the membrane 2 is smaller than the width W> of the top portion 38, which is smaller than the width Ws of the dike system 2. Accordingly, the relationship between the indicated widths Wy, Wz and W3 is given by the following equation: (2) W,>W,>W, It can be seen that the dike system 2 comprises a ditch 10 provided at the foot of the second inclined side 34. A detecting unit 25 configured to detect leakage of the membrane 4 is arranged in the membrane 4. Fig. 7 illustrates a schematic top view of a dike system 2 according to the invention.

The dike system 2 basically corresponds to the ones shown in Fig. 3-5. The membrane 4 is indicated with dotted lines.

The membrane 4 extends along a straight waterline and hereby protects the area behind the dike system 2 against flood from the water 24. A ditch 10 is provided at the foot of the second inclined side.

Moreover, a first pressure source shaped as a pump 22 is connected the left end portion of the membrane 4. Likewise, a second pressure source shaped as a pump 22' is connected the right end portion of the membrane 4. An outlet 23 is provided between the pressure sources 22, 22'. The out- let 23 is connected to a well 28 via a conduit 26. Hereby, the membrane 4 can easily be emptied by guiding the water into the well 28. This may be done by using a pump (not shown). In another embodiment it may be done by controlling a valve and emptying the membrane 4 by means of gravity only.

The dike system 2 comprises a liquid and gas assembly 54. The liquid and gas assembly 54 comprises the well 28, the conduit 26 as well as a gas source 52 and a second conduit 26’. The gas source 52 is config-

DK 181022 B1 22 ured to provide gas into the conduit 26 via a second conduit 26’. The liquid and gas assembly 54 also comprises a gas source 52 arrange d and configured to provide a gas flow into the conduit 26 via a second conduit 26”.

Accordingly, both liquid and gas can be filled into the inner space of the membrane 4. In one embodiment, the gas source 52 is a compressor having an inlet for allowing atmospheric air to enter and an outlet for guiding pressurised air into the conduit 26’.

It can be seen that the length L of the membrane 4 is much longer (more than ten times) than the width Wi of the membrane 4. Moreover, the length L of the membrane 4 is much longer (more than four times) than the width W3 of the dike system 2.

A pressure sensor 25 is arranged in the membrane 4. Hereby, it is pos- sible to leave a small quantity of water in the membrane 4 and use the pressure sensor 25 as a leakage sensor. In case of leakage, the pres- sure will drop to zero. The pressure sensor 25 may be equipped with a wireless transmitter unit (not shown), by which pressure measurement data can be transmitted to a receiver (e.g. a cloud-based receiver). In one embodiment, the pressure sensor 25 may be an integrated part of the membrane 4.

Fig. 8 illustrates a perspective view of a dike system 2 according to the invention arranged along a straight coastline and Fig. 9 illustrates a perspective view of a dike system 2 according to the invention arranged along an arced coastline. The cross-sectional area of the dike system 2 corresponds to the one shown and explained with reference to Fig. 3-6.

Fig. 10 illustrates a schematic cross-sectional view of a dike system 2 according to the invention in a configuration, in which the membrane 4

DK 181022 B1 23 is empty and Fig. 11 illustrates a view of the dike system 2 shown in Fig. 10 in a configuration, in which the membrane 4 is filled with water 24 and gas 50 in the form of atmospheric air.

The dike system 2 comprises a membrane 4 and a spike-like attach- ment member 12 inserted into the ground 16 in order to fix the mem- brane 4 to the surrounding ground 16. The membrane corresponds to the one explained with reference to Fig. 1-4.

Instead of covering the membrane 4 with soil or sand it is possible to cover the membrane 4 with a liner 44. In one embodiment, the liner 44 is a polypropylen liner. In one embodiment, the liner 44 is a heavy duty polypropylen liner. In one embodiment, the liner 44 is a polyester liner. In one embodiment, the liner 44 is a heavy-duty polyester liner. In one embodiment, the liner 44 is made in another suitable thermoplastic ma- terial.

The system 2 comprises a top layer 46 arranged on the top of the liner 44 in order to cover the liner 44. In one embodiment, the top layer 46 is made of artificial grass.

The system 2 comprises a mesh structure 8 arranged between the sur- face profile and the membrane 4. The mesh structure 8 is formed by a geonet (geotextile).

Fig. 12 illustrates a schematic view of a membrane 4 of a dike system according to the invention. The membrane 4 is illustrated in an inflated configuration and the height Hi; of the membrane is illustrated.

Fig. 13 illustrates a schematic view of a first membrane 4 and a second membrane 4’ of a dike system according to the invention. Both the first membrane 4 and the second membrane 4’ are inflated. It can be seen

DK 181022 B1 24 that the total height H> of the two membranes 4, 4’ is approximately twice as high as the height Hi of the first membrane 4. Fig. 14 illustrates a schematic view of a dike system according to the invention comprising a first membrane 4 and a second membrane 4’ placed on the first membrane 4. Both membranes are inflated. The first membrane is sealed by a first welding 51. The second mem- brane is sealed by a second welding 51’. The first membrane 4 compris- es a first extension portion 48, whereas the second membrane 4’ com- prises a second extension portion 48’ arranged on the top of the first extension portion 48. The two extension portions 48, 48’ extend parallel to each other. In Fig. 14, the extension portions 48, 48’ extend along the ground in a straight manner. A spike-shaped attachment member 12 is used to attach the extension portions 48, 48’ and thus the first membrane 4 and a second membrane 4' to the ground. The membranes 4, 4' shown in Fig. 12, Fig. and Fig. 14 are filled with water 24 as well as gas 50. The gas 50 may in particular be air.

Fig. 15 and Fig. 16 basically correspond Fig. 3 and Fig. 4. The mesh structure 8 and the liner 44 are, however, bent in such manner that they extend along the entire width of the membrane 4. Accordingly, the mesh structure 8 and the liner 44 support and stabilize the membrane 4 in its inflated configuration (as shown in Fig. 16).

DK 181022 B1 25 List of reference numerals 2 Dike system 4, 4' Membrane 6 Soil or sand 8 Mesh structure Ditch 12, 12' Attachment member 14 Surface profile 10 16 Ground 18, 18' Side portion 20 Fluid 22, 22' Pressure source (e.g. pump) 23 Outlet 24 Water 25 Detection unit (e.g. pressure sensor) 26, 26' Conduit 28 Well 30 Inner space 32 First inclined side 34 Second inclined side 36 Area 38 Top portion 40 First level 44 Liner 46 Top layer 48, 48' Extension portion 50 Gas 51, 51’ Welding 52 Gas source 54 Liquid and gas assembly o Angle

DK 181022 B1 26 Wi, Wz, W3 Width Hi, Hz, H3 Height L Length

Claims

DK 181022 B1 27 Patent claim

1. Dike system (2) comprising a waterproof membrane (4) defining an internal space (30) designed to receive and contain a liquid (20) thereby increasing the volume of the internal space (30), characterized in that the internal space (30) is filled with both water and a gas, where the gas volume is between 3 and 30% of the volume of the inner space (30).

2. Dike system (2) according to claim 1, characterized in that the dike system (2) comprises a detection unit (25) configured to detect leakage from the waterproof membrane (4).

3. Dike system (2) according to claim 1, characterized in that the detection unit (25) is: a) a pressure sensor (25) which is placed on the bottom area of the waterproof membrane (4) or b) a flow sensor (25) which is placed on the bottom area of the waterproof membrane (4).

4. Dike system (2) according to one of the preceding claims, characterized in that the membrane (4) is at least partially covered by a covering material (6).

5. Dike system (2) according to one of the preceding claims, characterized in that it comprises a first membrane (4) and a second membrane (4') which is placed on top of the first membrane (4).

6. Dike system (2) according to one of the preceding claims, characterized in that the dike system (2) comprises: a) a pressure source (22) or b) an inlet connection structure designed to be brought into fluid connection with a pressure source (22 ).

7. Dike system (2) according to claim 6, characterized in that the dike system (2) comprises an outlet connection structure that is designed to be brought into fluid connection with a receiving unit that is shaped and arranged to receive liquid from the dike system (2).

DK 181022 B1 28

8. Dike system (2) according to one of the preceding claims, characterized in that the dike system (2) comprises a plurality of fastening elements (12) which are designed to fasten the membrane (4) to the ground (16).

9. Dike system (2) according to one of the preceding claims, characterized in that the dike system (2) comprises a net structure (8) which is arranged between a surface profile (14) and the membrane (4).

10. Method for preventing the flooding of an area located behind a dike system (2), the method comprising the following steps: a) placing on the ground a waterproof membrane (4) defining an internal space (30) designed to receive and contain a liquid (20) and thereby increase the volume of the interior space (30), and b) filling a liquid (20, 24) in the interior space (30) to increase the volume of the interior space and thereby increase the vertical position of the upper part of the membrane and soil or sand (6) covering the membrane (4), where the membrane (4) is shaped as an elongated body part (32), characterized in that the method includes the step of filling gas (50) in the inner space (30) of the membrane (4), where the gas volume is between 3 and 30% of the volume of the inner space (30).

11. Method according to claim 10, characterized in that the method comprises the step of detecting whether the waterproof membrane (4) is leaky, where the step of detecting whether the waterproof membrane (4) is leaky is carried out using a pressure sensor (25), placed in the waterproof membrane (4).

12. Method according to claim 11, characterized in that the step of detecting whether the waterproof membrane (4) is leaking is carried out by means of a flow sensor (25) which is placed in the waterproof membrane (4).

13. Method according to any one of claims 10-12, characterized in that the method comprises the step of placing the membrane in a position in which the membrane is at least partially covered with soil or sand (6) or a liner.

14. Method according to any one of claims 10-13, characterized in that the method comprises the step of fixing the membrane

DK 181022 B1 29 (4) to the ground (16) by means of a plurality of spear-like fasteners (12).

15. A method according to any one of claims 10-14, characterized in that the method comprises the step of placing on the ground a first membrane (4) and placing a second membrane (4') on top of the first membrane (4) .