WO2023208309A2

WO2023208309A2 - An innovative system for the construction and operation of an artificial lake with a huge water body used for recreational purposes

Info

Publication number: WO2023208309A2
Application number: PCT/EG2022/050007
Authority: WO
Inventors: Gamal SOLIMAN
Original assignee: Emac Lagoons
Priority date: 2022-04-25
Filing date: 2022-06-17
Publication date: 2023-11-02
Also published as: WO2023208309A3

Abstract

Invention relates to an innovative system for the construction and operation of an artificial lake with a huge water body used for recreational purposes, as it is The characterized by presenting a method of constructing an artificial lake structure that includes a horizontal bottom extending to the edges by means of upward inclined slopes, where these slopes are formed by a pavement layer of Geocells ( Quaternary or pentagonal) made of HDPE installed on these slopes, and these cells are filled with clean sand or cohesive soil, and these inclined sides (slopes) extend from the bottom to the edges that are formed from a concrete slab along the axis of the lake. These edges consist of two parts, one of them is horizontal and the other inclined, at the end of this part, on the bottom side, an E-shape profile - made of the same insulating layer material - is installed, in addition to a new method for treating expansion and contraction joints in concrete edges and walls using EPDM rubber strips. Two layers of waterproof plastic polymers are installed over the surface of the lake including the bottom and slopes, in the middle of them is a geocomposite drainage layer to drain the leaking water from the upper layer. A semi-circular longitudinal drainage trench was formed at the bottom of the lake to collect the leaking water and direct it to a collection room outside the borders of the lake through a pipe connected to the trench. Within this system, an operation concept of the lake is also proposed that maintains the water body by using a mechanism for cleaning the bottom and surface of the water body and a process for treating the water mass.

Description

Title of Invention: An innovative system for the construction and operation of an artificial lake with a huge water body used for recreational purposes.

Technical Field

[0001] This invention relates to an innovative and integrated system for the construction and operation of an artificial lake used for recreational purposes such as swimming, recreation and water skiing. Since the construction method is characterized by ease of implementation and low cost compared to other methods and it provides a method of insulation that prevents the leakage of water through the waterproofing layers to the outside of the water structure, through an innovative construction technology for the water structure.

[0002] The invention also discloses an operating system for the maintenance of the structure that includes a mechanism for cleaning the bottom of the structure and the surface of the water through automatic sweeping device that collects and suctions sediments from the bottom, and another floating automatic device to scrape debris floating on the surface of the water.

Background Art

[0001] Nowadays, artificial lakes with clean blue water are one of the most important factors of attraction in most of the real estate development projects. Despite spreading of this element in these projects, the current construction methods for artificial lakes used in recreational activities have proven to have several deficiencies. The traditional construction method for building a recreational structure (lake) of water is to make a hole in the ground and cover the sides and the bottom with poured reinforced concrete or other types of concrete, such as shotcrete, and it has been proven that the cost of constructing recreational water lakes using this method of construction is very expensive for developers, and it requires a lot of time for implementation as the concrete requires a lot of working hours to be poured and it requires also use of a lot of construction equipment such as concrete pump trucks, and manpower to pour and smooth the concrete, and after all that the structure suffers from the presence of several joints in the concrete elements, therefore it is not possible to ensure that water will not seep out of the water body.

[0002] The other common method is to cover the hole bottom and sides with water impermeable plastics sheets instead of reinforced concrete. Although the cost of this method is lower, compared to the previous method, however, it has a disadvantage that the soil under the impermeable plastic layer, especially if the lake has tilted sides, is loose and unstable, and with the movement of the visitors and users of the lake on it, it moves and does not remain in a flat position, and the surface under the waterproofing layer becomes uneven with a lot of holes.

[0003] To solve this problem by traditional methods, the soil in these areas (inclined edges of the lake) is fixed using cemented sand. Through practical experience, this process is also useless, as it is done by mixing large quantities of sand and cement without adding water to the mixture, then spread this mixture on the inclined sides, and after leveling and compaction, it is sprayed with water, which is considered a very hard method, as the quantities to be mixed are large, and the areas to be covered with this mixture are huge, especially when constructing huge size lakes, and this process is very expensive as well. However, after spreading it and spraying water on the mixture, it turns from sand and cement into a cement plaster, which is a weak substance that cannot bear the movement on it.

[0004] As for the water body surface cleaning systems, the common methods of getting rid of floating debris on the surface of the water body are either manually using a plastic net attached to a long arm (usually 7 m long) held by the worker responsible for the cleaning process, standing at the wall (edge) of the swimming pool, to pick up the cuts of the floating debris on the surface of the water, or by installing fixed skimmers buried in the walls at the outer borders of the lake, and the manual method is used in small swimming pools where the amount of floating debris is small, it can be picked up manually using that net, while in large lakes, it can be used only near the edges of the lake where the arm of the skimming (cleaning) net cannot reach areas further from the walls (edges).

[0005] Also, relying on fixed skimmers buried in the walls at the borders of the lake to pick up and get rid of floating debris is not feasible, especially in the case of large lakes with large bodies of water. Since it is not conceivable that the debris will be automatically drawn and directed over a large distance into the skimmer opening, whose dimensions are within 25 x 40 cm, even assuming the presence of a thrust force from the wind or otherwise.

[0006] In traditional ways, devices are used to clean the structure bottom with a number of brushes in a way that allows the device to operate in both directions (front and back). Where the suction device is connected to an external filtering system, and these devices are equipped with a number of plastic safety wheels on the outer periphery of it to provide protection as the thrust force of the device is available through an external thrust device (boat), but the existing devices find it difficult to clean the bottom covered with a layer of plastics due to the presence of permanent wrinkles in the surface of this lining that hinder the work of these devices, and the device’s need for external thrust slows down its operation, and it increases the operating costs, and limits the possibility of maneuvering with the device.

[0007] The prior art also disclosed different ways to treat water in traditional swimming pools that work with one cleaning cycle of water, in which the filtration and sterilization processes are carried out through filters that retain impurities with the use of chemicals to sterilize the water mass, which are very expensive methods.

[0008] The previous technical references addressed different techniques for constructing and operating artificial lakes of all kinds, recreational, environmental, and treatment lakes, etc.

[0009] The Spanish patent no. ES2541320T3 of 2015 disclosed a process for the construction of reservoirs, swimming pools, fountains and artificial lakes in general, and it consists of the following stages: the excavation stage and the preparation of foundation layer of at least one layer of sand, clay or other suitable material, and placing one or more layers of non-woven fabric on the inner surface of the pit, and installing a waterproofing layer on the mentioned non-woven fabric layer and then disposing a layer containing stones, which is disposed together with a binder (slurry) so that it is homogeneously distributed in the interstitial spaces among the stones.

[0010] The Chinese patent no. CN105714741A of 2016 proposed a method for creating an ecological artificial lake where the bottom and inclined sides are formed of several layers of clay, bentonite, woven fabric and sand, with a protective strip of concrete at the edge of the lake to protect the previous layers.

[0011] The materials used in the bottom lining works in the two previous patents are suitable only in the case of small lakes that are not suitable for swimming or what is known as ponds, because they will not give the water the desired shape and color like swimming pools, nor did it provide any information about the water source or the treatment and preservation method. It was not mentioned that it is for recreational purposes, but it was only mentioned that it is an ecological lake. [0012] US Patent No. US10982400B2 of 2016 discloses the process of developing and preserving large bodies of water, and the process involves: providing a structure capable of containing a large mass of water, a water treatment system, feeding the structure with rainwater and groundwater, providing a supporting medium or rock aggregate that serves as a support for plants, The supporting medium or rock aggregate comprises a large number of plants that provide oxygen and nutrients to the open water lake system, and the water treatment lake system is provided with a modular system including sedimentation unit, wet plant filter, zooplankton pond, dry plant filter, biotreatment pond, and the final dry plant filter coupled with a cascade matrix, generating a water cycle so that the water to be treated from the open water lake system enters the water treatment lake system to retain the coarse sediments of liquid waste flow into the sedimentation unit and pouring the water into the wet plant filter where nutrients are retained, collecting water from the Zooplankton pond to direct it to the dry plant filter and then directs the water to the biotreatment pond where oxygen is added to water and the consumed organic matter is periodically added to the bacteria. Then water is sent from the biological treatment plant to the final dry plant filter that retains nutrients and sediments. The purpose of the subject lake of the present invention is different from the lake disclosed in US patent no. 400.

[0013] FR patent no. FR2740493B1 of 1995 provided a method for constructing a structure for swimming pools and artificial lakes used for recreational purposes without vertical walls. It consist of a flexible bottom extending to the edges of the mentioned structure, where the structure is formed of a paving layer consisting of hexagonal cells made of geocell fabric and these cells are filled with ordinary concrete where under this layer there is a drainage layer of geotextile, which in turn is located above the insulating layer of (plastic) below which there is a layer of fabric, provided that The bottom layer is a support layer consisting of a layer of compacted soil, above which there is a layer of sand, and below it a fine plastic net to prevent the intrusion of insects. Above this network there is a ground layer of the structure, as the main objective of the existence of the drainage layer in these layers represented in cleaning the bottom surface of the paving layer with a cleaning liquid through the drainage layer, where a means is placed in it to inject a cleaning liquid consisting of a sprinkler tube in order to clean the inner bottom surface of the paving layer where the function of the sprinklers is to operate under pressure to force the water into the drainage layer, directing the water towards the respective low drainage point so that the drainage liquid resulting from the sprinkler holes penetrates the thickness of the drainage layer, and the collected liquid gradually spreads to clean the inner surface of the paving layer. Then the remaining liquid gradually slides over the water-resistant plastic slat which is shaped with an inclination to help in sliding. The document also stated that the low drainage point is a basin connected to another pipe for treatment as it is connected to a water pumping unit.

[0014] It is clear that what was stated in this document differs from the used technology in the present invention, as the insulating layer is under the paving layer of hexagonal cells made of fabric and filled with concrete, which are immersed in the water of the lake. This will not give the water the bluish color required in such works because the color of the concrete will be apparent from water, but in the provided invention, the paving layer is made of hexagonal cells made of polyethylene and filled with cohesive soil (gray soil) and above it there are lining (waterproofing) layers with the required color. Moreover, the document did not provide a solution to the problem of preventing leakage in the event of a hit to the insulating layer, and the document did not state from near or far the existence of a trench which function is to collect the water leaking from the upper layer through the installed drainage layer until the water is collected in the trench and directed to the collecting chamber.

[0015] Egyptian Patent no. 26227 of 2013 shows a method for obtaining water bodies more than 15,000 m³ for recreational purposes with transparency and cleanliness properties similar to tropical swimming pools and seas wherein it states that “the structure or the pond (lake) according to the present innovation has bottoms and walls built of low-permeable materials, such as, clay and bentonite and covered with a non-porous layer etc.”, but the invention does not have a means to protect water from leakage if the non-porous layer is hit, as clay and bentonite, which cannot be applied to the sides and there is a difficulty of forming a lake using them as well, have porosity - even it is low - which cannot be relied on alone to preserve water from leaking.

[0016] The Egyptian patent no. 26773 of 2014 and the US patent no. US8062514 of 2010 disclose a structure to contain a large water body comprising a water body greater than 15,000 m³ for recreational use that has characteristics of color, transparency and clarity similar to those in tropical swimming pools or seas. The structure comprises a bottom and walls coated with a plastic lining made of a non-porous material that can be completely cleaned. The structure also comprises fixed skimmers to remove impurities and surface oils.

[0017] However, the document did not provide a description of the method of constructing the structure, nor did it provide a solution to the problem of water leakage from the structure in the event of a hit to (plastic lining made of a non- porous material), nor did it provide any description of the geometric shape of the borders of the structure and the way users enter to it.

[0018] Both of the previous inventions did not discuss how to form slopes so that their shape and levelling does not change with the use the visitors to the lake, nor did they provide a description of the geometric shape of the borders (edges) of the structure (lake) and the way users enter or exit it.

[0019] US Patent no. US1097604B1 of 2020 discloses a method for constructing a water basin for recreational water activities that involves: making a hole from the surface of the ground to form the water basin, forming soil at the bottom of the water basin with different lines and slopes where the bottom is covered with a synthetic fabric of Geosynthetic Cementitious Composite Mat above the bottom and slopes. Artificial reefs are formed for surfing. The composite cement fabric consists of a bottom layer and a top layer of woven fabric (Geotextile), and a lining of Portland cement between the two layers and then sprayed with water.

[0020] This invention has a disadvantage in the method of insulating the lake, as the flexibility of the composite cement fabric slats is not high and it has a high degree of permeability compared to the polymer plastic slats, such as, polyethylene and it is also difficult to repair in the case of a hit to the insulating layer.

[0021] The Brazilian patent no. BR102019004590B1 of 2020 discloses a construction and operation method for a scheme consisting of water channels which form islands or peninsula on which residential buildings are built surrounded by sandy beaches, and this water which is taken from an external source may be fresh or salty water, where a layer of reinforced concrete, clay soil or a plastic lining was used to isolate the channels, with a layer of clean sand disposed over the insulating layer at the bottom, sides and beaches. The water is treated with a flotation system without using filters where chlorine is added from several spots of water channels. [0022] The disadvantage of this method of constructing water channels is represented in the presence of sandy layer at the bottom and sides, as the sand, with the movement of water, will not be stable on the inclined sides, especially if it has a smooth plastic layer underneath, and as the time passes, the color of the sand changes and it needs to be changed every period. This requires emptying channels and spending huge sums of money.

[0023] Hence, it is found that there is an urgent need for an integrated method that provides solutions to these problems while maintaining operating efficiency and economic costs, which is provided by this invention, as all references, including any patents, patent applications or traditional methods cited in this specification are incorporated by reference, and there is no admission that any reference is part of the state of the art of the invention, because it does not address the innovative technology in the present invention.

Summary of Invention

[0001] The invention relates to an innovative system for the construction and operation of an artificial lake with a huge water mass used for recreational purposes, as it is characterized by providing a method of constructing an artificial lake structure comprising a horizontal bottom that extends to the edges through upward inclined slopes, where these slopes are formed by stretching a layer of geocell (quaternary or pentagonal) made of high-density polyethylene on these slopes. These cells are filled with clean sand or cohesive natural soil. These inclined sides (slopes) extend from the bottom to the edges that are formed of a concrete slab along the length of the lagoon axis, which consists of two parts, one part is horizontal and the other one is inclined, connected together, provided that an E-shape profile, made of the same waterproofing layer material, is installed at the end of this part on the bottom side. In addition, there is a new method for treating expansion and contraction joints in concrete edges using EPDM rubber slats, which are used for insulation by a fully bonded membrane to the concrete surface to be insulated. The two layers of water-impermeable plastics are spread over the entire surface of the lake including the slopes, in the middle of which there is a Geocomposite Drainage Layer to drain water leaking from the upper layer, with digging a semi-circular longitudinal trench at the bottom of the lake to collect water leaking to the collecting chamber outside the lake boundaries through a pipe connected to the trench. Within the framework of this system, a system for operating the lake is provided to maintain the lake by using a mechanism to clean the bottom and the water surface and a process for treating the water mass.

Technical Problem [0001] The main problem in the field of this invention lies in the cost of constructing recreational water lakes, as the traditional construction methods are very expensive for developers, and require a lot of implementation time, especially if the implementation is carried out in the common way using reinforced concrete in the construction of the lake structure, as concrete requires many hours of work to pour it and using a lot of construction equipment, and human power to pour and smooth the concrete, and it also needs painting the concrete surface with a suitable paint which in turn is very expensive and requires annual maintenance, and after all that preventing water leakage from the water body cannot be ensured.

[0002] As well as, upon constructing and operating artificial lakes for recreational purposes, the edges (borders) of the lake are exposed to the problem of preserving them. The edges and borders of the lake need what maintains its final shape over time, and preserves the edges of the impermeable insulating layer and at the same time to be convenient for the entry and exit of lake users.

[0003] Expansion and contraction joints are also one of the most important and complex problems facing concrete water structures, they are vertical joints that are made to allow the movement of expansion (or contraction) of the concrete elements of the structure horizontally according to the change in the temperature, and it is in the entire concrete sector and in specific places. Its task is to absorb the stresses resulting from the change in temperature and allow the concrete element to move during expansion or contraction, and it ranges from 2 to 5 cm thick.

[0004] Also, water structures that constructed from other traditional methods are exposed to water leakage from the lake as a result of a cut or rupture that may occur in the impermeable waterproofing layer during construction or over the lifetime of the lake, as during the construction process, this layer is exposed to a great and certain risk of damage because it is exposed to weather factors during the construction period, which takes a long time. Damages may also occur during the life of the lake as a result of operating works (such as periodic cleaning of the lake bottom), and all these damages are difficult to be discovered, located easily, or to be repaired and to be dealt with. Hence the importance of finding a way to prevent water leakage outside the water structure in the event of damage the waterproofing layer. As this may lead to many damages such as loss of part of the water mass, damage to the environment as a result of raising the groundwater level in the surrounding area, damage to the foundations of the surrounding facilities of the water structure as a result of the rise in the groundwater level, the consumption of mechanical systems responsible for operating the water structure, and the increase in the rate of consumption of electrical energy needed to operate the water structure, and other such damages.

[0005] The surface of the water mass is also exposed to the presence of floating debris on the surface of the water. As a natural result of the use of the lake for swimming by quite a few people, old and young, water pollution occurs. This pollution may be biological from the secretions of swimmers’ bodies. This needs a system to sterilize the water. The pollution may be floating debris and waste such as leaves, plastic bags, empty bottles, dead insects, etc., which if left without being dealt with, part of this floating debris will eventually sink to the bottom of the lake, making the cleaning task more difficult, and the other part remains floating on the surface of the water, which represents an actual and visual source of pollution to the water body.

[0006] Also, the accumulation of sediments at the bottom of the structure leads to pollution of the water mass, which necessitates the need to carry out cleaning work for the bottom, and in the case of large artificial lakes and huge reservoirs, the work of cleaning the bottom consumes a lot of time and effort, and the difficulty increases if the bottom is uneven or if the water structure is lined with waterproofing plastic sheets, which always have wrinkles that hinder the cleaning process.

[0007] Water treatment and maintaining it in a good condition represent the largest part of the operating cost, as the activities necessary for water treatment, such as, filtration, chemical additives, and the necessary equipment and electrical energy, consume a lot of money to maintain water quality.

Solution to Problem

[0001] Hence the importance of finding an innovative solution that comprises a distinctive construction method for the structure of an artificial lake that does not allow water to leak out of the structure, and an operating system that maintains the water structure through an innovative system to construct and operate an artificial lake with a huge water body used for recreational purposes.

Advantageous Effects of Invention

[0001] The system is characterized by many features that make it achieving the desired goals and that make it working with high efficiency, as the problem of water leakage outside the structure was overcome by implementing an innovative construction technique that is different from the recognized techniques in this field. The invention provided an easy and powerful way to form the slopes of the water structure to preserve them from the movement of the visitors. It provides also a method to preserve the edges and borders of the lake and its final shape, and to install and preserve the edges of the waterproofing layer, as well as the method of treating expansion and contraction joints in concrete edges and vertical walls using rubber sheets to insulate water and allow the movement of concrete elements without causing any cracks or breaks. It provides also a waterproofing system that comprises spreading water-impermeable plastic layers that prevents water from leaking, from the upper layer when it is damaged, outside the structure of the lake, with the development of a system for the operation and maintenance of the water structure, such as cleaning the surface of the water and the bottom of the water structure and water treatment by purification and sterilization, which maintains water quality.

Brief Description of Drawings

[0001] Figure 1] shows the shape and method of spreading geocells on slopes.

[0002] [Figure 2] shows a plan view of a lake with an area of 10,000 m² where the elements of the lake construction are shown such as the lagoon axis 2, bottom 3, inclined sides (slopes) 4, concrete edges 8 and vertical walls 19.

[0003] [Figure 3] shows the elements of the lake through a cross section, showing the section of the lake 1 and its axis 2, the bottom 3 and the slope 4 and the natural soil 5 and the horizontal base layer 6 spread on the bottom 3 and the layer of geocells 7 spread on the slope 4 and the concrete edges 8 above the slope, which consists of two parts the first is horizontal 9 in the direction of the beach sand 11 and the second is inclined 10 in the direction of the bottom 3. It shows the waterproofing layers spread on the bottom and the sides, which consist of a colored top layer 13 and a black lower layer 15 and a composite drainage layer 14 between the two layers where the two upper layers 13 and the lower layers 15 are installed and welded in the E-shape profile 12, which was installed in the concrete of the edge 8 during pouring.

[0004] [Figure 4] shows a isometric view of the lake, showing the main elements such as the bottom 3, the natural soil 5, the horizontal base layer 6, the slopes covered with a layer of geocells 7, the concrete edges 8, which consists of two parts, the first one is horizontal 9 and the second one is inclined 10 and vertical walls 19.

[0005] [Figure 5] shows an isometric section showing the lagoon axis 2, the natural soil 5, the horizontal base layer 6, the geocells 7 spread on the slopes, the concrete edges 8 with its horizontal part 9 and the inclined one 10, the upper impermeable layer 13 and the lower 15 and the drainage trench 16 in which there is the formation 17 made of the same material as the composite drainage layer and a pipe 18 to drain the water collected in the trench 16 and finally the vertical walls 19.

[0006] [Figure 6] shows the details of the vertical wall 19, showing the lagoon axis 2, the bottom 3, the natural soil 5, the horizontal base layer 6 and the vertical wall parts, which consists of the vertical part 25 and the horizontal base 26 and shows the installation of the E-shape profile 12 at the foundation 26, which is installed during pouring.

[0007] [Figure 7] shows the details of treatment of the expansion and contraction joint 20 where both sides of the joint 21 are sanded and cleaned, a slat of rubber EPDM 22 is adhered and coated with poly aspartic 23 after its treatment.

[0008] [Figure 8] shows the details of the formation shape 12 to be made of the same material of the waterproofing layer.

[0009] [Figure 9] shows a perspective section of the lake bottom 3 showing the upper waterproofing layers 13 and the lower ones 15, and in between there is composite drainage layer 14, the collecting trench 16, and the cylindrical formation 17 made of the same material of the drainage layer.

Description of Embodiments

[0001] According to this invention, the proposed system consists of an innovative technology to create an artificial lake used for recreational purposes such as swimming, recreation and water skiing. The construction method is characterized by relying on the technique of spreading several layers of different construction materials, so that the lake structure acquires the advantage of insulation for any water leakage outside the body of the lake 1 . The system also includes a proposed system for the operating works in the lake 1 , where the operating works here mean the necessary cleaning operations for the water mass (which has been purified and treated). As these cleaning operations are among the tasks that affect the design and implementation of the structure of the lake 1. They are carried out continuously to maintain the quality of the water mass. They are divided into two processes; the first process is concerned with cleaning the bottom of the lake 3 and the second one is concerned with cleaning the surface of the water in the lake 1. [0002] Where the construction method starts from choosing the appropriate site to construct the structure of the artificial lake 1 , the site for the implementation of the lake is selected according to the general scheme of the project. Upon selecting the site, it is taken into account to be close to the water source that the lake will be filled from and the water losses of the lake by the evaporation will be makeup from it, whether this source is an underground well or sea or otherwise. It is also taken into account that the groundwater level in the area is not higher than the design level of the lake bottom 3, so that the uplift forces do not to affect the lake bottom 3, and this also includes the level of tide if the location of the lake is close to the sea. Then the step of selecting the construction site will be followed by the excavation works and the formation of the lake structure. Lake 1 is formed in soil 5 by excavation to the required depths. The excavation depth is determined according to the required depth of the water plus at least 35 cm. For swimming purposes, the water depth ranges between 1 .2 and 1 .4 m, therefore, the depth of excavation ranges at least from 1.55 to 1.75 m. However, if the use of the lake comprises water sports, such as water skiing, the depth of the water must not be less than 2 m, then the excavation depth is at least 2.35 m, and the object of the depth increase 35 cm in the water depth is that the water surface level must be less than the level of the edges of the lake 8 by at least 15 cm, and the rest (20 cm) is the thickness of the base layer 6 that is put on the lake bottom 3.

[0003] The base layer 6 may be selected from a pit-run gravel, which is a soil widespread in Egypt and is characterized by its red color as it contains iron oxides. It also contains graded aggregates and about 10% of alluvial and clay materials. This soil is characterized by its strong cohesion when compacted after being sprayed with water, therefore it is frequently used in the base of roads.

[0004] The present invention relates to the construction of an artificial lake 1 of a type comprising a bottom 3 extending to the edges 8 by slopes 4 gently inclined upwards towards the edge, such slopes 4 represent the entrance to the lake users. The angle of inclination of the slope must provide comfort to the user in movement in and out from and to the lake 1 , in order to allow safe access to the lake, especially for children and the elderly. The codes of the architectural designs (specifications) state that the comfortable inclination for pedestrians and people with special needs ranges between (2.5-10%) and if it ranges between (12.5- 20)%, it will be valid for pedestrians only, provided that it is equipped with balustrades with handles. Through practical experience, the inclination slope for the comfortable and appropriate entrance to the lake ranges between 10% and 12.5%, and full care must be taken to implement it, as these slopes 4 represent the place of entrance and exit for the lake visitors, therefore it is always subject to dynamic loads resulting from the movement of entrance and exit of visitors. Through practical and previous experiences, it was found that the compacted sand or the cemented sand does not bear these loads and after a while these slopes become full of holes and uneven, which hinder walking on them and make them difficult to clean, and the use of concrete in their formation is very expensive as well, and the shapes of lakes are often irregular and have curved borders, so the formation of these slopes 4 is difficult.

[0005] To solve all these problems, it is provided in this invention a method for forming the slopes 4 forming the sides of the lake 1 by spreading a layer of geocell 7 made of high-density polyethylene on the slopes 4 of quadrilateral or pentagonal shapes, and filling these cells with clean sand or cohesive soil and with a thickness of 7 to 10 cm. These cells 7 increase the durability of the slopes 4 for the loads of walking on them, and it also facilitates the formation of the slopes 4 with them, especially in areas with curved sharps.

[0006] The slopes 4 forming the sides of the lake 1 start from the bottom 3 and directed upwards towards the edge 8, which are formed (ie, the edge) of reinforced concrete to maintain the shape of lake 1 and to be the element of separation between the sandy beach 11 surrounding the lake and the lake water and from which users enter the lake. It consists of a concrete slab along lagoon axis 2 with a thickness ranging from 15 to 40 cm and it is formed by two connected parts, the first part is horizontal 9 and starts from lagoon axis 2 heading outward towards the sandy beach 11 around the lake and with a width of not less than 1 .5 m. The level of the concrete top surface in this part shall be higher than the water level in the lake by a distance of not less than 15 cm.

[0007] The second part is inclined 10 and starts from the lagoon axis 2 and goes inward and is inclined to the same degree of inclination of the slopes of the lake 4 and with a width of not less than 4 m. The level of the concrete top surface in this part is the same as the level of the layer of geocell 7 laid on slope 4. At the end of this part on the bottom side 3, and during concrete pouring and before it dries up, a continuous E-shape profile 12 of the same material as the lake insulation layer is installed so that the flat part is visible from the concrete after drying. [0008] Sometimes, and in order to install some mechanical equipment, it is required that the formation of the edges, in specific places, represents vertical concrete walls, and these walls 19 consist of two parts, the first part is the body of the vertical wall 25, which starts from the level of the lake bottom 3 and ends at a level higher than the water level in the lake with a distance not less than 30 cm, and the second one is the foundation of the wall 26 and it is horizontal so that the level of the top surface of the concrete foundation is the same level as the bottom of the lake. The thickness of the concrete of the vertical part 25 and the foundation 26 is subject to the structural design of the wall, and in the foundation part from the lake side, during concrete pouring and before it dries up, a continuous E-shape profile 12 of the same material as the lake insulation layer is installed so that the flat part is visible from the concrete after drying.

[0009] Since the edges of the concrete lake 8 are of large lengths, expansion joints 20 must be made for the entire concrete section of the edge slab to absorb the stresses resulting from the change in temperature and allow the concrete element to move during expansion or contraction. As the Egyptian code for the design and implementation of concrete structures (Code no. 203 of year 2017, Clause 9-6-8) states that “the maximum distance between the expansion joints for normal installations ranges from 40 to 45 meters in moderate regions, and from 30 to 35 meters in hot regions, and it may be allowed for these distances to increase provided that it is taken into account when designing temperature differences and the effect of expansion, contraction and creep factors, and it is generally emphasized that all precautions are taken to ensure that cracks do not occur and to prevent water or dust leakage from the joint”.

[0010] The use of the water stop 24 in the joint during pouring is not sufficient only to prevent water leakage, as its task is to lengthen the path of the water and only hinder it. Upon implementing, honeycombing often occurs in concrete at the water stop, which facilitates the leakage of water through it. The materials used to fill and treat expansion joints are valid only in case that the joint is far from water, and some methods are used, such as Sika Combiflex, in case light water may exist, such as expansion joints in roof tiles, but it is not suitable in the case of water structures where the joint is always immersed in water.

[0011] The invention discloses an innovative method for dealing with joints 20 of all kinds, expansion and contraction joints are the most difficult, upon constructing artificial lakes, whether the joints are in the horizontal concrete edges 8 or they are in the vertical walls 19, by using a longitudinal sheet with a width of not less than 25 cm of Ethylene Propylene Diene Monomer (EPDM) rubber 22 which is a material of flexible rubber in the form of sheets (rolls) used in insulation by fully bonded membrane to the concrete surface to be insulated, using a special adhesive that is painted on the concrete surface before disposing the rubber sheets. After it is completely dry, it becomes very sticky to it. The proposed method is implemented by cleaning the joint first of the concrete excesses or any materials that may hinder the expansion or contraction movement. Then the two sides of the joint 20 are sanded with a width of 10 cm on each side using an emery machine, and painting both sides of the joint 21 with an adhesive rubber substance, then a rubber sheet EPDM 22 is disposed along the joint and left it to dry. After complete drying, sheet 22 is painted with phosphoric acid, which makes its surface capable of being painted with poly aspartic 23 in the required color. It is found that this material is the only one suitable for painting rubber after treating it with the aforementioned acid, because rubber by its nature does not stick to different paint materials, and the rubber sheets is black which is an undesirable color. The joint is painted in the same color used in painting the entire concrete edges. The concrete edges and vertical walls may be painted in a color that matches and is consistent with the color of the insulating layer 13 in order to give a beautiful shape to the lake as a whole, so that the paint material is a colored one, resistant to sunlight, resistant to acids, salts and chemicals, and it is also impermeable to water, such as, poly urea or poly aspartic, poly urethane, or other similar.

[0012] The lake waterproofing system consists of two layers 13 and 15 of impermeable plastics, such as, PVC or HDPE or other similar, with a thickness ranging between 0.75 and 3 mm, which is spread over the entire surface of the lake including the slopes 4, It is welded into a E-shape profile 12 that is previously fixed in the edges’ concrete 8 in the inclined section 10 or at the foundation of the vertical walls 26. The upper layer 13 is colored in a suitable color to help in making the lake water looks beautiful, and with a rough surface to prevent the slipping of the lake users while entering or exiting the lake, and between the two layers, there is a geocomposite drainage layer 14 with a thickness ranging from 5 to 25 mm. Its task is to drain leaking water from the upper layer 13 if a tear or a cut occurred. This leaking water is collected in a drainage trench 16. Drainage Trench is a longitudinal semi-circular pit at the bottom of the lake with a depth starting from 10 cm from the beginning and the end and the depth increases as we go towards the middle, because there is a slope of not less than 0.3% at the bottom of trench 16, so that the lower impermeable layer 15 is formed in the shape of a trench 16. The trench 16 is filled by disposing a cylindrical formation 17 made of the same drainage layer 14 material, then the upper impermeable layer 13 is spread over this formation 17. The task of this trench 16 is to collect the water leaking from the upper layer 13 and directs it towards the midpoint where there is a pipe 18 connected to the trench and welded in the lower non-permeable layer 15 and passing at the bottom of lake 1 below the waterproofing layers to a collecting chamber outside the boundaries of the lake 1 , where the water that is leaked from lake 1 is collected and is pumped back to the machine room by a suitable submersible pump. Therefore, when a damage occurs to the upper impermeable layer 13, which is exposed all the time to weather factors during the construction period or to operating factors throughout the life of the lake, it is ensured that the leaking water will not go out of lake 1 where the leakage of lake water into the external environment leads to many damages such as loss of part of the water mass, damages to the environment as a result of raising the level of the groundwater in the surrounding area, damage to the foundations of the structures surrounding the lake as a result of the rise in the level of the groundwater, consumption of mechanical systems responsible for its operation, and increase of the rate of consumption of the electrical energy required for operation, and other such damages.

[0013] Within the framework of the proposed system, it was necessary to propose an innovative operating system for the maintenance of the water mass in lake 1 , as the method of cleaning the lake affects its design and the way its structure is implemented. This process is carried out continuously to maintain the quality of the water mass in it, and it is divided into two processes, the first one is concerned with cleaning the bottom of the lake and the second one is concerned with cleaning the surface of the water in the lake.

[0014] The bottom of the lake 3 is cleaned of the sediments deposited on it resulting from the dust in the surrounding atmosphere or the use of the visitors and so on, using a huge battery-powered sweeper that contains a number of suction holes and brushes that collect the sediments and direct them to the suction holes. The device moves on rollers and movement belts on both sides of the device, and it is directed using the remote control, and it pumps the water mixed with sediment and sucked from the bottom 3 through a hose with a diameter of not less than 150 mm to fixed points distributed on the borders of the lake, and they are in the vertical parts 19, and connected to the suction pump where water is collected in a sedimentation tank.

[0015] As for cleaning the surface of the water mass, whether small such as swimming pools or large ones such as huge artificial lakes, it needs removing floating debris and waste such as tree leaves, dead insects, plastic bags and other pollutants, which, if left without dealing with, part of this floating debris will eventually sink to the bottom of lake 3, making the clean-up task more difficult, and the other part will remain floating on the surface of the water, representing an actual and visual source of pollution to the water body.

[0016] Debris floating on the surface of the water body can be removed manually using a plastic net attached to a long arm (usually 7 m long) held by the operator responsible for the cleaning process, standing at the wall (edge) of the pool, to pick up the floating debris on the surface of the water. This method is used in small swimming pools where the amount of floating debris is small, it can be picked up manually using that net, but in large swimming pools it can only be used near the edges of the swimming pool where the arm of the scraping net cannot reach the areas far from the walls (edges) of the swimming pool.

[0017] Fixed skimmers are widely used in swimming pools of all kinds for this purpose. It is a box with a hole fixed in the side walls (vertical edges) of the swimming pool so that the water level is at the middle of its hole, and it has a basket to hold the debris and it is connected to the pool pump, where it works on scraping the surface of the water supported by air currents and the water motion resulting from the swimming of the individuals and the suction of the pool pump when it is operated. The Egyptian code (Code 301-1999, p. 90-91 ) states that “The number of skimmers units installed in public swimming pools is calculated on the basis of at least one unit for every 46.5 m² (500 square feet) of water surface in the public swimming pool, and one unit for every 74.5 m² (800 square feet) of water surface for private swimming pools”.

[0018] These requirements if applied efficiently in swimming pools, their implementation in huge artificial lakes and large water bodies faces difficulty in implementation because the implementation of the previous requirements in huge lakes requires the use of a very large number of skimmers, for example, the artificial lake in the Central Parks area in the New Administrative Capital has a water surface of 90,000 m² and a circumference of about 2000 m. According to the Egyptian code, this lake needs 1936 skimmers distributed on its external borders. This is a very large number that is impossible to install as it requires a huge network of pipes, and it also raises the cost of construction and raises the cost of daily maintenance and operation.

[0019] Also, for the purpose of pulling debris from the surface of the water, skimmers are installed, as above, buried in the walls (outer edges) 19 of the water body. In the case of huge lakes, the surfaces are large, and the distance between the center of the water body and the edge is also large. Referring to the previous example (the Central Parks Lake in The New Administrative Capital), the distance between the center of the water surface and the nearest edge reaches 80 meters in some places. It is inconceivable that the debris in this area will move automatically through this long distance to enter the hole of the skimmer, whose dimensions are within 25 x 40 cm.

[0020] Because the circumference of the water structure is also large, the distribution of skimmers uniformly on the boundary, as took place in swimming pools, is not feasible with the limited number of skimmers that are actually planned to be installed, so the designers distribute the skimmers on the exterior circumference of the water body so that it is concentrated in the predominant direction of the wind motion in the lake area. As large artificial lakes often have a more complex geometric shape than swimming pools, and the directions of wind motion change from time to time, it is found that it is difficult to distribute the skimmers so that all floating debris above the water is withdrawn through it, and often a part of this debris is collected at the walls and edges of the lake away from the skimmers in a harmful view of the general shape of the lake.

[0021] The invention discloses a method to avoid the problems of the difficulty of carrying out scraping of waste from the surface of the water previously mentioned, where the implementation of the fixed skimmers is canceled and the floating moving skimmer is used that is navigating on the surface of the pool water to devour the floating debris and clean the surface of the water. These skimmers are proved to be highly efficient in cleaning swimming pools, but in large artificial lakes, the skimmer used must be remotely directed, since it requires navigating for long distances without wires, and also the debris collecting basket must also be large to accommodate the large quantities which may be found in such lakes, and also it must be equipped with sensors that prevent it from colliding with the edges of the lake or any floating object in it (such as, children's floating toys). [0022] The invention also disclosed a technique for treating the water mass by purifying and sterilizing impurities and microorganisms that infect the water. Until the system proposal was completed through the innovative operating system, it was necessary to find an economical and effective way to purify water with large water bodies which is used for recreational purposes. The method is characterized by combining the sterilization and purification process by passing the water mass over the filters and adding the flocculation agent in one water cycle.

[0023] The sterilization process relies on the use of ultrasonic devices as the main means of the sterilization process in the body of the water structure itself, then sterilized water is pumped from the water structure to the sedimentation tank after passing it to the injection chamber to add the coagulant agent to precipitate flocculants and dirt in the conical part of the tank. The water in the upper part becomes filtered from the impurities to be pumped to the filters and returned to the water structure through the entrance openings at the bottom 3.

Claims

[Claim 1] method of constructing an artificial lake structure, comprising a bottom extends to the edges with inclined slopes upwards by spreading a layer of quadrilateral or pentagonal geocells made of high-density polyethylene (HDPE) on the slopes, and these cells are filled with clean sand or cohesive soil. The edges of the structure are formed of a concrete slab that extends along the lake axis, and it consists of two horizontal and inclined parts connected together. A mold in E-shape profile which is made of the same material as the waterproofing layer is installed at the end of the inclined part on the bottom side, and two layers of impermeable plastics are applied to the entire surface of the lake, including the slopes, in the middle of them is a geocomposite drainage layer for draining the water leaking from the upper layer with the excavating of a longitudinal semi-circular trench at the bottom of the lake to collect the leaking water from the upper layer to the collecting chamber outside the boundaries of the lake through a pipe connected to the trench.

[Claim 2] The method of constructing an artificial lake structure according to claim 1 , where the bottom of the lake extends to the edges with inclined slopes, in order for the angle of inclination of the slope to achieve comfort for the user in the entrance and exit movement from and to the lake.

[Claim 3] The method of constructing an artificial lake structure according to claim 2, where the formed slopes for the sides of the lake are formed by laying a layer of quadrilateral or pentagonal geocells made of high-density polyethylene on the slopes.

[Claim 4] The method of constructing an artificial lake structure according to claim 3, where these cells are filled with clean sand or cohesive soil, and their thickness ranges from 7 to 10 cm.

[Claim 5] The method of constructing an artificial lake structure according to claim 3, where the formed slopes for the sides of the lake start from the bottom and go up towards the edge, which are made of reinforced concrete to maintain the shape of the lake.

[Claim 6] The method of constructing an artificial lake structure according to claim 5, where the formed edges from a concrete slab extending along the lagoon axis with a thickness ranging from 15 to 40 cm, or from a vertical concrete wall in specific places.

[Claim 7] The method of constructing an artificial lake structure according to claim 6, where the concrete slab is formed from two connected parts, the first part is horizontal and the second one is inclined.

[Claim 8] The method of constructing an artificial lake structure according to claim 7, where the first horizontal part begins from the lagoon axis heading out towards the sandy beach with a width of not less than 1.5 m, and the level of the top concrete surface in this part is higher than the water level in the lake with a distance of not less than 15 cm.

[Claim 9] The method of constructing an artificial lake structure according to claim 7, where the second part begins from the lagoon axis inward and is inclined with the same degree of inclination as the slopes of the lake and with a width of not less than 4 m, and the level of the top concrete surface in this part is the same level of the geocell layer spread over the slope.

[Claim 10] The method of constructing an artificial lake structure according to claim 9, where it is fixed at the end of this part on the bottom side during concrete pouring and before it dries, an E-shape profile mold of the same material as the lake waterproofing layer so that the flat part is the visible part of the concrete after being dried.

[Claim 11] The method of constructing an artificial lake structure according to claim 6, where the vertical walls consist of two parts, the first part is the body of the vertical wall, which starts from the level of the lake bottom and ends at a level higher than the water level in the lake by a distance of not less than 30 cm, and the second one is the foundation of the wall and it is horizontal so that the level of the top surface of the concrete foundation is the level of the bottom of the lake.

[Claim 12] The method of constructing an artificial lake structure according to claim 11 , where it is fixed to the base of the horizontal wall from the side of the lake during concrete pouring and before drying an E-shape profile mold of the same material as the lake waterproofing layer so that the flat part is the visible part of the concrete after being dried.

[Claim 13] The method of constructing an artificial lake structure according to claim 6, where the concrete edges and vertical walls are painted in a color that matches and is consistent with the color of the insulating layer in order to give a beautiful shape to the lake as a whole.

[Claim 14] The method of constructing an artificial lake structure according to claim 6, where the paint material is colored, resistant to sunlight, resistant to acids, salts and chemicals, and is also impermeable to water, such as, poly urea, poly aspartic, poly urethane, or other similar.

[Claim 15] A method for treating expansion and contraction joints in concrete edges, where a longitudinal sheet with a width of not less than 25 cm is used of a rubber material used in insulation by entire adhesion to the concrete surface to be insulated, where the adhesive substance is painted on the concrete surface before disposing the rubber sheets, which become very sticky after drying them.

[Claim 16] A method for treating expansion and contraction joints according claim 15, where joints are treated with Ethylene Propylene Diene Monomer (EPDM) rubber.

[Claim 17] A method for treating expansion and contraction joints according claim 15, where the method comprises the following steps: a. Clean the joint of concrete excess or any materials that may hinder the expansion and contraction movement. b. Sanding both sides of the joint, with a width of 10 cm on each side, using an emery machine. c. Paint both sides of the joint with rubber adhesive. d. Dispose an EPDM rubber sheet along the joint and allow it to dry. e. Paint the sheet with phosphoric acid, which makes its surface capable of being painted with poly aspartic in the required color, as the rubber sheet is black, and the joint is painted with the same color used for painting the entire concrete edges.

[Claim 18] The method of constructing an artificial lake structure according to claim 1 , where two layers of water-impermeable plastics such as PVC or HDPE, with a thickness ranging between 0.75 and 3 mm, are spread over an entire flat surface of the lake including the slopes.

[Claim 19] The method of constructing an artificial lake structure according to claim 18, where the upper layer is colored in an appropriate color to assist in making the shape of the lake water looks beautiful.

[Claim 20] The method of constructing an artificial lake structure according to claim 18, where the upper layer has a rough surface to prevent the users of the lake from slipping while entering or exiting it.

[Claim 21] The method of constructing an artificial lake structure according to claim 18, where the two layers are welded in the E-shape profile that is fixed in the concrete edge, whether the inclined part or the foundation of the vertical walls.

[Claim 22] The method of constructing an artificial lake structure according to claim 18, where a geocomposite drainage layer whose thickness ranges between 5 to 25 mm is in the middle of the two waterproofing layers, to drain the water leaking from the upper layer if a rupture or cut occurs.

[Claim 23] The method of constructing an artificial lake structure according to claim 22, where the leaked water is collected in a drainage trench, which is a semi-circular longitudinal pit at the bottom of the lake, with a depth of 10 cm from the beginning and the end, and the depth increases as we move towards the middle.

[Claim 24] The method of constructing an artificial lake structure according to claim 23, where there is a slope of not less than 0.3% at the bottom of the trench, to form the lower impermeable layer in the trench shape.

[Claim 25] The method of constructing an artificial lake structure according to claim 23, where the trench is filled by a cylindrical formation of the composite drainage layer, and then the upper impermeable layer is extended over this formation.

[Claim 26] The method of constructing an artificial lake structure according to claim 23, where there is a pipe connected to the trench and welded in the lower impermeable layer and passing at the bottom of the trench below the waterproofing layers to the collecting chamber outside the boundaries of the lake.

[Claim 27] The method of constructing an artificial lake structure according to claim 26, where the collected water that leaked from the lake is pumped back to the machine room by means of a suitable submersible pump.

[Claim 28] The method of constructing an artificial lake structure according to claim 1 , where the method of constructing an artificial lake is characterized by obtaining a water-insulating structure that ensures that water does not leak from the body of structure to the outside.

[Claim 29] An operating system for maintaining the water mass in the artificial lake, where the system comprises two processes for cleaning the lake, where the first process is concerned with cleaning the bottom of the lake and the second process by cleaning the surface of the water, and a third process for purifying and sterilizing the water mass in the lake.

[Claim 30] An operating system for maintaining the water mass in the artificial lake according to claim 29, where the lake bottom is cleaned of sediments using a huge battery-powered sweeper and it contains a number of suction openings and brushes that collect the sediments and direct them to the suction openings.

[Claim 31] An operating system for maintaining the water mass in the artificial lake according to claim 30, where the device moves on rollers and movement belts installed on the right and left of the device, to be directed using the remote control.

[Claim 32] An operating system for maintaining the water mass in the artificial lake according to claim 30, where the water mixed with sediments and sucked from the bottom is pumped through a hose with a diameter of not less than 150 mm to fixed points distributed on the lakes’ borders and connected to the suction pump where this water is collected in a sedimentation tank.

[Claim 33] An operating system for maintaining the water mass in the artificial lake according to claim 29, where the surface of the water body is cleaned to remove floating debris and wastes, using a moving floating skimmer that is navigating on the surface of the lake water to devour the floating debris.

[Claim 34] An operating system for maintaining the water mass in the artificial lake according to claim 33, where the skimmer is directed remotely, and it comprises a large basket for collecting debris, with sensors that prevent it from colliding with the edges of the lake or any floating object therein.

[Claim 35] An operating system for maintaining the water mass in the artificial lake according to claim 29, where the process of treating the water mass is carried out by purifying and sterilizing impurities and living organisms that infect the water, by combining the sterilization and purification processes by passing the water mass over the filters and adding a flocculation agent in one water cycle.

[Claim 36] An innovative system for the construction and operation of an artificial lake with a huge water mass used for recreational purposes, where it comprises a method for constructing an artificial lake structure that is characterized by an insulating technique against any water leakage outside the structure and a method for treating expansion and contraction joints in the concrete edges, where the structure consists of two waterproofing upper and lower layers and a middle drainage layer to drain the water leaking from the upper layer. The structure also comprises a semi-circular longitudinal trench at the bottom of the lake to collect the water leaking from the upper layer to the collecting chamber outside the lake borders, in addition to a lake operating system that works on maintaining the lake through using a mechanism for cleaning the bottom and water surface structure and the process of treating the water mass i