AU2003246047A1 - Aquadam - Google Patents

Description

Field of the Invention This invention relates to the design and construction of a dam positioned in an ocean, sea, lake or other large body of water instead of within a freshwater river system. The concept is more environmentally sound and does not rely on the collection of rainwater only.

Background of the Invention We need water for irrigation, industrial use, residential homes and drinking.

Typically fresh water is drawn from rivers, aquifers and wells. As population increased, countries around the world constructed larger dams within river systems to retain, capture and store quantities of fresh water for constant long-term supply.

Especially drought-affected areas rely on dams.

The ecological consequences on a worldwide basis of these river-based dams are being realised today. In order to store large quantities of water, the natural environment is destroyed around the riverbeds, wildlife and human populations are displaced, and the bio-diversity of the whole river estuary is changed forever. The long-term effects are the most controversial part of the land-based dams. As the water is stored at the upper parts of the river systems, the capacity of the water flow is sometimes reduced to a trickle. Especially in drought season, both plant and animal life are severely affected.

Up until just recently, the obvious benefits of a river-based dam were that you can guarantee the water supply pending on consistent rainfall and that they create a controllable flood mitigation regime. Additionally dams are by their very nature a storehouse of energy and when the water is released they can generate renewable power.

The benefits of the Aquadam are numerous. Firstly, fresh water is collected from several sources instead of relying solely on rainfall. Secondly, it eliminates the longterm environmental degradation of whole eco-systems that river-based dams create by alleviating the dependency on these fresh water supplies. Subsequently, the strain on river systems can be reduced by increasing water flow.

In the 2 1 st century, the need for fresh water is increasing exponentially but as the people realise the long-term ecological damage that river-based dams cause and on the principle of NIMBY (Not In My Backyard) it will be politically unacceptable to continue constructing dams within river systems of the world.

Summary of the Invention The present invention is to address the ever-increasing challenge of providing fresh water without the adverse effects to the environment. This invention allows the utilisation of resources without the long-term permanent damage to the surrounding areas. A construction of a dam based in the ocean can be changed, repositioned or removed with very little environmental consequences.

Another objective of the invention is to provide a new and improved dam (that we have named "Aquadam") to guarantee adequate supply of fresh water to nearby towns, cities and farming regions. This can be accomplished by employing any one Page 1 of or any combination of the following: catchment of rainfall, desalination of salt water, and collection of stormwater.

The Aquadam is designed to be positioned within a large body of water (eg: ocean, sea, lake, etc) and would be ideally situated within close enough proximity to land so that it can service nearby populations. For example, to service the population of a capital city on the Australian mainland, an Aquadam would be ideally located in the ocean within approximately one to twenty kilometres offshore. The Aquadam is designed to float within the host body of water (ie: ocean, sea, lake, etc) and in broader terms can be either totally submerged, raised above the host water level or preferably level with the host body of water. Preferably, the walls of the membrane protrude out of and above the host body of water enough so that the risk of contamination is reduced.

The membrane of the Aquadam is ideally shaped to be hydrodynamic to reduce the effect of movement such as wave action, currents, tides, etc. The size and total volumetric capacity of the membrane are subject to the volume requirement of fresh water. Preferably the membrane would measure approximately 2000 metres long by 1000 metres wide, or 3000 metres long by 1500 metres wide, or 4000+ metres long by 2000+ metres wide. The maximum depth of the membrane when completely filled is subject to the depth of the host body of water and would preferable by approximately metres to 250 metres.

The membrane of the Aquadam is designed to be flexible enough so that it can "collapse" and fold up on itself from the bottom up when emptied, and also unfold and "expand" from top down to maximum depth when filled. Initially the membrane floats on the surface of the water and then as fresh water is introduced into the membrane, it unfolds such that the base of the membrane sinks a depth into the host body of water relative to the amount of water that it holds.

Preferably, the perimeter of the membrane is attached to several flotation devices such that the membrane remains buoyant and rises and falls with the tide. Also attached to the exterior of the membrane are one or more platforms that can be used for such things as supporting infrastructure (eg: treatment plants, warehouses, control rooms, factories, maintenance facilities, stations, etc) as well as structurally supporting the shape of the membrane, assisting with stabilising the membrane and preventing contamination in the Aquadam from the host body of water. Preferably, the platform(s) would be affixed to one or more pylons that would assist with anchoring the membrane to maintain its position in the host body of water. Alternatively, the position of the membrane can be maintained by employing one or more submerged containers containing ballast that would be anchored to the seabed. Preferably there is one platform at each of the two ends of the membrane that are supported by pylons and have a fixed height above the maximum level of the host body of water (ie: sea level). These platforms support the majority of the infrastructure on the Aquadam.

Alternatively, these platforms are supported by flotation devices and are therefore able to rise and fall with the tide.

The membrane is a single compartment that contains the whole body of pre-treated fresh water. Alternatively the membrane is divided into two or more compartments that are interconnected and pumped from independently.

Page 2 Servicing the Aquadam is a series of three or more water treatment plants located either on land or preferably on the platform of the Aquadam. These treatment plants can be summarised as follows: 1. Treatment of host body of water (ie: desalination of salt-water, etc); 2. Treatment of stormnwater; 3. Final treatment of water to make it potable. Preferably the stormwater treatment plant would be divided into a primary plant located on the land for initial treatment and removal of large debris and nonsoluble particles and a secondary plant located on the Aquadam platform for further treatment. Preferably the desalination plant(s) and the final treatment plant(s) are also located on the Aquadam platform. It is an obvious potential that the desalination plant could be a mobile floating unit (eg: on a large ship or some other vessel) that draws water from the host body of water and depositing the fresh water either into the membrane of the Aquadam or pumped directly into the well(s) on land.

After the water has been treated, it is stored in a fully enclosed reservoir that is preferably located beneath the platform and either partially or completely submerged in the host body of water. One or more pipes are connected to the freshwater reservoir with flexible connection(s) preferably at the base of the reservoir. The other end of the pipe(s) is connected to one or more wells situated on land such that water can flow from the reservoir to the well(s). A pumping station(s) is situated next to or close to each well to pump freshwater to the population. Alternatively, the well(s) is attached by pipe(s) directly to connections on the outside of the membrane of the Aquadam.

Naturally, the water level inside the well(s) is equal to the water level of the host body of water, and therefore equal to the water levels inside the membrane and the reservoir. The fresh water can flow freely from the reservoir to the well(s) without the need for it to be physically pumped.

The structure of the Aquadam has the potential to support one of or a combination of several methods of generating renewable energy, such as wind, wave, tidal and solar.

The benefits of utilizing any of these sources of renewable energy are that they are environmentally sound, energy efficient and non-polluting. Also, the Aquadam can preferably use a combination of renewable energy methods (ie: any combination of wind turbines, wave turbines, tidal wheels/turbines, solar cells/panels and any other current technology) as each of these energy sources is readily available and abundant where the Aquadam is situated (ie: ocean, sea, lake, etc).

A self-contained energy generation plant is preferably located on the platform and provides some of or all of the energy to operate the desalination plant as well as the other mechanics and operations.

If desalination is used, the brine extracted from the salt water can be deposited and dissolved back into the host body of water, preferably several kilometres beyond the Aquadam.

There is potential to collect water into the Aquadam from another source, namely the river systems.

Page 3 TABLE 1. MONTHLY RAINFALL TOTALS (Gold Coast. Old Australia) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Canungra 23.8 43.4 88.6 22.0 28.6 64.8 2.8 55.6 13.6 24.0 75.6 114.8 Nerang 19.4 28.2 98.4 74.2 53.6 80.2 1.2 117.6 36.0 32.4 77.8 155.6 Oxenford 34.2 44.6 128.0 74.6 88.0 66.0 6.0 112.0 12.4 43.8 44.6 141.6 Southport 41.7 48.6 122.8 103.8 127.4 70.0 1.0 147.8 23.2 41.2 55.0 23.4 Mt Tamborine 41.6 55.6 88.8 55.4 49.2 83.2 4.0 105.6 13.2 31.2 44.8 182.2 Miami 23.2 67.0 118.0 106.2 69.6 60.0 0 102.6 29.8 57.2 81.4 140.0 Coomera 38.6 32.6 139.0 90.6 120.2 62.2 1.4 110.6 18.2 72.0 47.6 140.7 Hinze Dai 16.0 20.0 101.8 5.2 34.2 iii iii48.6 0.6 iii 1.8 3.4 25 ili0.0 123.2lii i iiiiii Springbrook 64.4 92.2 204.0 143.2 76.6 101.0 4.0 117.8 25.8 36.6 91.2 165.0 Coolangatta 58.0 134.4 95.8 143.6 98.8 62.4 2.6 119.6 41.0 107.6 110.8 115.8 Seaway 43.6 39.0 118.4 86.4 106.4 55.2 2.4 143.4 23.0 66.4 40.2 125.8 Beechmont 15 41 104 49 28 62 4 68 11 24 43 140 Binna Burra 22 64 131 62 28 63 3 87 14 20 81 108 Reference: Gold Coast Bulletin Newspaper, 09/01/2003 Table 1 above shows the amount of rainfall collected at the Hinze Dam on the Gold Coast and the rainfall for several other suburbs in the region. The rainfall over the unshaded regions is directed to the ocean and lost as stormwater. The Aquadam has the ability to collect and store this extra water.

Detailed Descriptions of the Figures Figure 1 is a plan view (aerial shot) of a preferred apparatus for collection, filtration and storage of water according to an embodiment of the invention; Figure 2 is a side view of the apparatus of Figure 1.

Figure 1 illustrates the collection of stormwater into a storage pond 1 to be filtered by a filtration unit 2 and then stored in a storage tank 3. The filtered stormwater in the storage tank 3 is transported to a secondary filtration unit 4 via an underwater pipe 17.

Once the stormwater completes secondary filtration, it is deposited into the dam membrane 9 for storage. The dam membrane 9 is divided into several compartments by walls 11. The dam membrane is supported by several pylons 10 which are anchored into the seabed. Two platforms 7 and 8 are situated at the ends of the dam membrane 9. One of the platforms 7 supports the secondary filtration unit for stormwater 4, a desalination unit for seawater 6 and a final filtration and treatment unit 5. The desalination unit 6 collects seawater for filtering and deposits the recovered freshwater into the dam membrane 9. The final filtration unit 5 draws water from the dam membrane 9 for filtering and deposits the completely treated water into a freshwater reservoir 12. An underwater pipe 18 transports the water from the freshwater reservoir 12 to several storage wells 13, 14 and 15 situated on land. A pumping station 16 draws the water from the storage wells 13, 14 and Figure 2 illustrates the power generation for the operation of the apparatus. Several wind turbines 19 are situated near the tops of the support pylons 10. Several wave turbines 20 are situated underwater below the base of the dam membrane 9 and attached to the pylons 10. A power station 21 is situated on one of the platforms 8 and generates power for the operation of the apparatus.

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Claims (15)

1. a method to construct a dam to be positioned in a large host body of water, preferably several hundred metres offshore, for the purposes of collecting, filtering (and desalinating) and storing a large quantity of water;

2. a method of claim 1, wherein the design of the Aquadam is hydrodynamic;

3. a method of claim 1, wherein water is collected from several sources;

4. a method of claim 3, wherein rainwater is collected directly over the area of the dam;

5. a method of claim 3, wherein stormwater is collected into a storage on land;

6. a method of claim 3, wherein freshwater is recovered from the surrounding host body of water by desalination and collected into the dam;

7. a method of claim 1, wherein collected water is filtered by several filtration units;

8. a method of claim 7, wherein a filtration unit filters and pre-treats stormwater to be piped to the secondary filtration unit;

9. a method of claim 7, wherein a filtration unit carries out secondary filtration of the stormwater to be deposited into the dam; a method of claim 7, wherein a filtration unit desalinates the seawater from the surrounding host body of water and deposits it into the dam;

11. a method of claim 1, wherein filtered water is stored in the dam;

12. a method of claim 7, wherein a filtration unit further filters and treats the fresh water from the dam to make the water potable;

13. a method of claim 11, wherein the potable water is stored in an enclosed reservoir;

14. a method of claim 1, wherein potable water is transported via pipes to one or more wells situated on land for storage; a method of claim 1, wherein a pumping station pumps the water from the wells;

16. a method of claim 1, wherein the wall of the Aquadam is sufficiently raised above sea-level to prevent salt water contamination;

17. a method of claim 1, wherein renewable energy (ie: wind, wave, solar and tidal) is generated on-site for the energy requirements of the Aquadam. Page