WO2010006368A1 - System and method for mitigating evaporation from reservoirs - Google Patents
System and method for mitigating evaporation from reservoirs Download PDFInfo
- Publication number
- WO2010006368A1 WO2010006368A1 PCT/AU2009/000906 AU2009000906W WO2010006368A1 WO 2010006368 A1 WO2010006368 A1 WO 2010006368A1 AU 2009000906 W AU2009000906 W AU 2009000906W WO 2010006368 A1 WO2010006368 A1 WO 2010006368A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- connector
- buoyant
- sheeting
- water
- edges
- Prior art date
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B3/00—Engineering works in connection with control or use of streams, rivers, coasts, or other marine sites; Sealings or joints for engineering works in general
-
- E—FIXED CONSTRUCTIONS
- E03—WATER SUPPLY; SEWERAGE
- E03B—INSTALLATIONS OR METHODS FOR OBTAINING, COLLECTING, OR DISTRIBUTING WATER
- E03B3/00—Methods or installations for obtaining or collecting drinking water or tap water
- E03B3/04—Methods or installations for obtaining or collecting drinking water or tap water from surface water
Definitions
- This invention relates to water storage and dams and reservoirs for water storage, and in particular to a system and method for mitigating losses through evaporation from open topped dams and reservoirs.
- the preferred (low-cost) solution would be to cover the water with a thin layer of buoyant, water-impermeable and flexible, plastic or fabric (hereafter called 'fabric').
- 'fabric' buoyant, water-impermeable and flexible, plastic or fabric
- a connector for buoyant sheeting used to mitigate evaporation from a body of water, said connector being elongate to extend along an edge of buoyant sheeting or between edges of adjacent buoyant sheeting and having a plurality of fixing means located along the longitudinal extent of said connector, said plurality of fixing means being located on an upper surface thereof, to secure edges of said buoyant sheeting thereto.
- said plurality of fixing means are located in a position recessed from an upper surface of said connector, in order to provide greater streamlining of said connector against forces imparted by wind, when in use.
- said plurality of fixing means comprises fixings each spaced apart from each other by a predetermined distance.
- the buoyant sheeting is provided with complementary fixings along its edges, aligned with the fixings of said connector, so a plurality of said buoyant sheeting can be secured along its edges to a plurality of said connectors extending therebetween.
- each fixing is selected from one of the following:
- said connector is neutrally buoyant or slightly heavier than water.
- the connector is preferably of a specific gravity so that it is restrained against sinking by the buoyant sheeting, but not sufficiently light that the connector sits higher in the water than the buoyant sheeting. This arrangement ensures that the connector does not produce any lift through sitting proud in windy conditions.
- said connector has a specific gravity of from 1.0 to 1.1.
- said connector has a specific gravity of from 1.0 to 1.075.
- said connector has a specific gravity of from 1.0 to 1.05.
- said connector has a specific gravity of from 1.0 to 1.025.
- said connector includes an opening or a plurality of openings along the longitudinal length thereof, extending from said upper surface of said connector to a lower surface of said connector.
- any water lying on the buoyant sheeting may run off into the main body of water comprising the reservoir. This water may be collected from rainfall or from the reservoir itself due to disturbance such as wind.
- the openings also allow contact with air to assist in aeration of the water in the reservoir.
- said connector comprises a pair of parallel members extending along the longitudinal axis, and each fixing comprises a pair of said fasteners, one located on each member, said members being spaced apart and rigidly joined by a plurality of transverse struts.
- said connector comprises a pair of parallel tubular members extending along the longitudinal axis, and each fixing comprises a pair of said fasteners, one located on each member, said members being spaced apart and rigidly joined by a plurality of transverse struts.
- each said tubular member is formed from plastic pipe, and is partially filled with a settable composition leaving an air space thereabove to provide the required buoyancy in said connector.
- a system for reducing evaporation from a body of water in a reservoir or dam comprising pieces or lengths of buoyant sheeting provided with connection means along edges thereof, said system including connectors as described above for connecting to said connection means by said plurality of fixing means of said connectors, said connectors being provided to join said pieces or lengths of buoyant sheeting to adjacent pieces or lengths of buoyant sheeting.
- connection means comprise a plurality of eyelets spaced apart from each other by a predetermined distance, corresponding to the predetermined distance the fixings are spaced apart on said connector.
- a plurality of said connectors extend continuously along edges of said buoyant sheeting to connect to edges of adjacent lying buoyant sheeting on the surface of the body of water.
- outer edges of said buoyant sheeting on the surface of the body of water are provided with connectors as described above extending along the outer edges, to provide a tether point to anchor the system to a shore or edge surrounding the body of water.
- said buoyant sheeting comprises a length of buoyant sheeting dispensed from a roll.
- said buoyant sheeting has a light coloured or reflective upper surface, to reflect light and minimise heating of water that it overlies when in use.
- buoyant sheeting is flexible.
- buoyant sheeting is impermeable to water.
- buoyant sheeting is formed with apertures extending from one surface to the other to release any gas forming therebelow.
- a method for reducing evaporation from a body of water in a reservoir or dam comprising providing pieces or lengths of buoyant sheeting provided with connection means along edges thereof, and providing connectors as described above for connecting to said connection means by said plurality of fixing means of said connectors, said connectors being provided to join said pieces or lengths of buoyant sheeting to adjacent pieces or lengths of buoyant sheeting to form a two dimensional array of pieces or lengths of buoyant sheeting joined along their edges by said connectors extending across substantially the surface of the body of water.
- the connectors provide rigidity to the array and resistance against drift due to forces which may be imparted by windy conditions that the array might be subjected to.
- the array may not necessarily extend across the entire surface of the body of water, and indeed the edges of the body of water may remain exposed to provide space for anchoring ropes and tensioning arrangements which may otherwise damage or be impeded by any buoyant sheeting that extends thereacross.
- connection means of said buoyant sheeting
- said connection means comprise a plurality of eyelets spaced apart from each other by a predetermined distance, corresponding to the predetermined distance the fixings are spaced apart on said connectors.
- a plurality of said connectors extend continuously along edges of said buoyant sheeting to connect to edges of adjacent lying buoyant sheeting on the surface of the body of water.
- outer edges of said buoyant sheeting on the surface of the body of water are also provided with connectors as described above extending along the outer edges, to provide a tether point to anchor the system to a shore or edge surrounding the body of water.
- This arrangement is preferred as it assists in spreading the load between the tethering ropes and the buoyant sheeting.
- said buoyant sheeting comprises a length of buoyant sheeting dispensed from a roll.
- said buoyant sheeting is flexible.
- the invention can, in its most preferred form, be described as a modular system of interconnected floating fabric sheets covering a water body with the following capabilities:
- Figure 1 is a plan view of a connector according to the embodiment
- Figure 2 is a cross section of the connector of figure 1 , showing it connected to buoyant sheeting adapted for use therewith;
- Figure 3 is a plan view showing one deployment an array of buoyant sheeting according to the method and system of the invention.
- Figure 4 is a plan view showing another deployment an array of buoyant sheeting according to the method and system of the invention.
- Figure 5 is a longitudinal elevation showing deployment of the array of figure 3;
- Figure 6 is a plan view corresponding to figure 5;
- Figure 7 is a longitudinal elevation showing an alternative installation of the system of the invention.
- Figure 8 is a longitudinal elevation showing another alternative installation of the system of the invention.
- the embodiment is a system and method for reducing loss of water through evaporation from reservoirs, and a connector for used with buoyant sheeting in the system and method.
- the connector is illustrated.
- the connector is in the form of a float 11 of neutral buoyancy and elongate construction, being a nominal 970 mm long, a nominal 360 mm transverse width, and a nominal 140 mm vertical height.
- the float 11 has two parallel members each in the form of tubular members being ultra violet stabilised plastic pipe 13 and 15.
- the plastic pipes 13 and 15 are spaced apart and joined by transverse struts in the form of transverse rods 17 made of steel which is galvanised or otherwise coated to prevent rusting.
- the transverse rods 17 are spaced apart from each other to support the pipes 13 and 15 relative to each other.
- the spacing apart of the pipes 13 and 15 by the transverse rods 17 provides an opening 19 between the pipes 13 and 15, which extends all the way through from an upper surface or extent 21 to a lower surface or extent 23 of the float 11.
- the plastic pipes 13 and 15 are sealed at their opposed ends by caps 25.
- other means such as foam plugs could be employed instead of caps.
- the plastic pipes 13 and 15 are provided with a plurality of fixing means in the form of fixings 27 29 31 and 33 which are spaced apart from each other along the longitudinal extent of the float 11 , by a predetermined distance.
- Each of the fixings 27 29 31 and 33 comprises a pair of fasteners in the form of bolts or studs 35 37, provided one bolt or stud 35 37 extending out of each plastic pipe 13 15 respectively (spaced apart longitudinally along each plastic pipe 13 15 by the predetermined distance).
- the fixings 27 are located below the upper surface or extent 21 of the float 11.
- the pipes 13 and 15 with assembled transverse rods 17 are partly filled with concrete 39 or another settable substance heavier than water, to an extent sufficient to render the float almost neutrally buoyant when placed in a water body.
- the concrete 39 or other settable composition must be sufficiently rigid to prevent the transverse rods 17 being pulled out, or alternatively the transverse rods 17 can be formed with a kink which rests within the settable composition to prevent disengagement.
- the extent that the settable composition fills the float will depend on its specific gravity.
- the float 11 should be buoyant to the extent that it floats just contacting the surface of the water.
- Each float 11 is used to connect to adjacent buoyant sheeting 41 and 43.
- the portion of the buoyant sheeting along and adjacent to the edges 45 are provided with connection means in the form of eyelets 47 spaced according to the same predetermined distance as the spacing of the fixings 27 29 31 and 33 on the float 11.
- Each eyelet 47 is connected to a bolt or stud 35 37 and secured by a locking nut such as a nylock nut 49 (and washer 51 ), thus securing each buoyant sheet 41 and 43 to a respective pipe 13 and 15.
- the floats 11 shown in figures 1 and 2 are used fitted along both the longitudinal edges 53 and transverse edges 55 of adjoining buoyant sheeting, fusing/forming them into one large 'blanket' 57 which would cover most of water surface of a typical reservoir 58 as shown in figure 3.
- ropes or cords 59 which may be elastic or inelastic, connected to onshore pins or small anchor piles 61.
- the edge of the 'blanket' could be anchored directly onshore by a row of anchor pins 65, driven into the bank material through eyelets in the fabric.
- the first sheeting 41 (a) would be installed, and successive sheets would be installed, commencing with sheeting 43 (b) and sheeting 43' (g), on either edge of sheeting 41.
- the buoyant sheeting 41 is provided on a roll 67, which is mounted on a spindle 69 for dispensing.
- the buoyant sheeting 41 is pulled off the roll 67 in the direction indicated by arrow 71 by a small - trailerable - craft 73, connected by tow ropes array 75 which are secured to end floats 11.
- buoyant sheeting 41 During the towing process, further floats 11 are fixed to the side edges 77 of the buoyant sheeting 41 as soon as it makes contact with the water surface 79. Once the buoyant sheeting reaches the shore opposite the roll, it is secured in position. An adjacent roll of buoyant sheeting 43 is unrolled and floats are affixed along the edge thereof, opposite the buoyant sheeting 41 already in position, as the buoyant sheeting 43 is being extended. Once fully extended, the buoyant sheeting 43 is secured to the floats already in position attached to the buoyant sheeting 41. Further buoyant sheeting is added in similar fashion until the reservoir is covered to the desired extent, forming a blanket of buoyant sheeting connected by floats.
- buoyant sheeting can be placed in a pre-dug trench 83 which would subsequently be filled by compacted soil, crushed rock, limestone, cemented sand or concrete 85.
- Optional weights 87 can be placed at regular intervals to hold down the buoyant sheeting and/or to keep it under some tension.
- the 'blanket' 57 is anchored by ropes or cords 91 , connected to small anchor piles or stakes 93.
- the 'blanket' 57 would be kept under constant tension, irrespective of the fluctuating water levels in the reservoir, by means of weights 95 which are hung from the ropes 91.
- the downward force of the weights 95 is compensated by the buoyancy of special end floats 97 which are more buoyant than the other floats 11 through not being filled with concrete.
- a higher water level in the reservoir is illustrated, along with the configuration of the system of this embodiment, in dashed outline. It should be noted that only limited tension in the buoyant sheeting is required to prevent significant downwind shifting of the blanket, even during the most severe storm conditions.
- leaves and any other forms of debris heavier than water can be brushed or hosed into the water through the openings 19 between the pipes 13 and 15 of the floats 11.
- Man-made rubbish such as, for example, plastic bags and natural materials lighter than water, such as twigs and branches, would be manually collected and removed. This can be done by workers traversing the buoyant sheeting on short skis or in pontoons, punts, shallow inflatables or canoes of a type with rounded hulls which allow them to traverse in any direction, across both the buoyant sheeting and the floats 11.
- the load spreading effect of skis in combination with the trampoline effect of fabric tension and the tension introduced through the rope anchoring, would reduce foot (or hull) subsidence to, at most, a few inches.
- the most effective arrangement for cleaning and maintenance would be a small portable pontoon of light material with little draught (ideally not exceeding 50 mm) would be most effective. It could be pulled lengthwise along a blanket sheet via auxiliary pull rope, which while being used could be sufficiently tensioned at both shore ends to prevent the pontoon from being shifted sideways by any strong cross winds. It would easily slide over the buoyant sheeting and floats and would provide a rotationally stable platform for the cleaner or cleaners.
- a compact water jetting unit with its intake alongside the pontoon could be utilised to jet debris off the buoyant sheeting and onto the floats, where it may pass through the apertures in the floats. Larger or floating debris can be manually retrieved and transported on the pontoon.
- the buoyant sheeting is a woven polypropylene that is treated to be waterproof and ultraviolet stable. Such sheeting is buoyant and flexible.
- the polypropylene sheeting or a covering layer is light in colour or reflective, so as to minimise heating of the water through incident sunlight. While other flexible sheeting known in the art for covering domestic swimming pools and domestic spa pools may be used, this is more expensive than the polypropylene product.
- a composite including polypropylene or another buoyant material including polypropylene or another buoyant material.
- the upper face or layer of the material is one which is light in colour or reflective, so as to minimise heating of the water through incident sunlight.
- the polypropylene layer may be bonded to overlie a layer of buoyant sheet which may be a foamed plastic sheet or plastic sheet incorporating an array of air bubbles. With the upper layer of the buoyant sheeting being of polypropylene, this minimises friction, easing the sliding of watercraft thereover.
- the buoyant sheeting should be waterproof to minimise losses due to evaporation.
- the buoyant sheeting requires sufficient tensile strength to be able to safely cope with the maximum drag force induced by storm winds and/or the weight of maintenance personnel. For long life, the buoyant sheeting needs a high level of UV light protection. It is recommended that the upper surface of the buoyant sheeting is pale, preferably white or silver, in order to maximize sunlight reflection. This keeps the covered water body relatively cool, and could compensate for thermal losses that would otherwise occur through evaporation, minimising the impact on aquatic life in the reservoir. This, and the effective shielding from sunlight, can assist in minimising algal growth. Part of the water surface would remain uncovered, to the extent that natural aeration of the water body either through edges that are uncovered, and/or via the openings 19 in the floats 11 would remain high enough to ensure the well being of fish and other forms of aquatic life.
- the buoyant sheeting can be perforated with small vent holes in order to allow the escape of gasses generated during the anaerobic decay of organic material in the reservoir or at the base at the reservoir. This would effectively prevent the formation of gas pockets below the buoyant sheeting, ensuring that the buoyant sheeting material would remain in direct contact with the water at all locations at all times.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Structural Engineering (AREA)
- Mechanical Engineering (AREA)
- Civil Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Public Health (AREA)
- Water Supply & Treatment (AREA)
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Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2009270331A AU2009270331B2 (en) | 2008-07-15 | 2009-07-15 | System and method for mitigating evaporation from reservoirs |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2008903617 | 2008-07-15 | ||
AU2008903617A AU2008903617A0 (en) | 2008-07-15 | Aquaseal |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2010006368A1 true WO2010006368A1 (en) | 2010-01-21 |
Family
ID=41549926
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AU2009/000906 WO2010006368A1 (en) | 2008-07-15 | 2009-07-15 | System and method for mitigating evaporation from reservoirs |
Country Status (2)
Country | Link |
---|---|
AU (1) | AU2009270331B2 (en) |
WO (1) | WO2010006368A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB895820A (en) * | 1960-03-07 | 1962-05-09 | British Petroleum Co | Improvements in or relating to floating covers suitable for use in storage tanks |
GB1470839A (en) * | 1974-02-13 | 1977-04-21 | Labeguerie L | Covering device for a swimming pool |
GB2368091A (en) * | 2000-10-18 | 2002-04-24 | Claude Joseph Degarie | Floating cover for large liquid reservoir |
US20030066789A1 (en) * | 2001-10-05 | 2003-04-10 | Agri Covers, Inc. | Covering systems and venting methods |
WO2007065198A1 (en) * | 2005-12-08 | 2007-06-14 | Paul Dalley | Mineral tank floating cover and method of vapour recovery |
-
2009
- 2009-07-15 AU AU2009270331A patent/AU2009270331B2/en not_active Ceased
- 2009-07-15 WO PCT/AU2009/000906 patent/WO2010006368A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB895820A (en) * | 1960-03-07 | 1962-05-09 | British Petroleum Co | Improvements in or relating to floating covers suitable for use in storage tanks |
GB1470839A (en) * | 1974-02-13 | 1977-04-21 | Labeguerie L | Covering device for a swimming pool |
GB2368091A (en) * | 2000-10-18 | 2002-04-24 | Claude Joseph Degarie | Floating cover for large liquid reservoir |
US20030066789A1 (en) * | 2001-10-05 | 2003-04-10 | Agri Covers, Inc. | Covering systems and venting methods |
WO2007065198A1 (en) * | 2005-12-08 | 2007-06-14 | Paul Dalley | Mineral tank floating cover and method of vapour recovery |
Also Published As
Publication number | Publication date |
---|---|
AU2009270331A1 (en) | 2010-01-21 |
AU2009270331B2 (en) | 2016-02-18 |
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