285 m3), please also consider the stacking arrangement : No. Quick. This product can bear up to 62 tonnes and is 1m x 0. The crates are designed to be simply and easily stacked together to create a below ground storm water holding tank or to allow the infiltration of storm water into the ground around them. Chamber Depth. water storage. The stored rainwater can then be slowly released into the sewer system, reducing the risk of flash floods. Stormwater Retention, Attenuation and Infiltration The Polypipe Polystorm Cells can be mainly used for rainwater Retention, Attenuation, Infiltration. 216 m3 0. This product can bear up to 65 tonnes and is 1m x 0. 2m3 per crate. the EcoBloc stormwater attenuation crates have a gross volume of 205 litres and are made from 100% recycled plastic. £58. What are attenuation crates? Attenuation crates, also known as soakaway crates, are used to control the level of surface water and reduce the risk of flooding. They are also suitable for use beneath car parks. 4 m³ with an approx. 1m high (3. The drainage system and water storage-permeation and filtration system along side the roads, parking lot, water storage and drainage for the ecological shallow ridges, living community, factories. With a design that ensures that solids are. . Buried 0. Of our clients recommend us. As leading specialists, we can also provide you with a stormwater attenuation installation service. Chat now. Quantity. Control and manage your rainwater surface water runoff – our storm crates can be used for both attenuation or ground infiltration in a variety of applications. The water is then released from the. permeable paving and cellular/crate attenuation systems. Buried with 0. 5 m maximum installation depth; Connection DN 100 (4") on top; Pins for vertical connection already included in packaging unit; 3. Optimised design, engineered to last. Stormbloc® Stormwater Storage / Infiltration System A modular system with an integral patented maintenance / inspection tunnel. Whether you need to hold stormwater (detention system), soak water away (infiltration system) or detain water to release at a controlled rate (attenuation system), RainSmart will provide a simple, cost effective and maintainable underground stormwater management solution for your site. This below ground Rain Bloc crate is a simple an effective way to form a Soakaway or attenuation tank. From £3,669. Infiltration Tank #M2016S. €POA. AquaCell NG is designed primarily for landscaped. Cover depth. Modern stormwater management solutions allow for local rainwater treatment, attenuation, infiltration and/or reuse — offering a more efficient, economical, and environmentally friendlier alternative to conventional drainage systems. Alternatively, fill out our enquiry form:The attenuation tank crates/blocks are placed to the predetermined laying pattern, before holes for inlet, outlet and vent pipes are cut to size. Easy to handle and install. We are able to offer a one-stop soluation for this. From £269. Stormwater Attenuation Tank | Soakaway Crates | Infiltration Tanks | Modular. The crate structure is surrounded with a permeable non-woven geotextile to prevent any ingress of silt to the crate structure. The units are stackable which creates a huge stackable underground holding tank to allow infiltration of water into the ground around them. Stormwater Attenuation & Infiltration Crates • Cellular stormwater attenuation crates • Ideal for domestic soakaways • 3. The stored water inside the attenuation tank is released via a flow-control chamber and is either pumped via a pumping chamber or run-off through a gravity stormwater pipe system. The drainage system and water storage-permeation and filtration system along side the roads, parking lot, water storage and drainage for the ecological. 0138 m3 (void ratio 95. GF512 500x500x 120mm (Green Roof Trays, Green Roof Modules) GF520 500x500x 200mm / GF530 500x500x 300mm (Green Roof Trays, Green Roof Modules) Features. com. Wavin AquaCell units are a tried and tested modular technique for managing excessive rainfall and can be assembled to create an underground structure as either a temporary attenuation tank or infiltration soakaway. Specialists in stormwater management and rainwater harvesting systems, SCP Water Management Ltd. The AquaCrate decreases the inconvenience of flooding during heavy rainfall, with rainwater “cleaned” by the geotextile surround. The crates have multiple integral shear connectors built into each unit that locate into the crate below. Complete crate weighs 11. The stormwater is then released from the storage tank at a controlled rate, usually by a flow control, which means that the surface water run-off will be slowly released into a local water course like a river or reservoir, therefore minimising. For both commercial and domestic properties. (Other depths available to order). Back SubmitTo achieve this, a stormwater retention system would be required to capture and store the water on site. Its flexible modular structure is light but strong, making it ideal for use beneath areas such as roads, car parks and industrial areas. Description. The crates are designed to be easily stacked together to create a below ground storm water holding tank or to allow the infiltration of storm water into the ground around them. It has a 61 tonnes/m² compressive strength and is manufactured from over 90% recycled material content. Try to ensure that the sides and bottom of the excavation are straight and square. Hybrid SuDS. We can also offer an installation service if required. Download our FREE information pack to discover: GRAF Stormwater Management Systems. The crates are a single piece and can be easily maneuvered, stacked and placed. Our Pipelife Stormbox is the heart of our stormwater management system. Brett Martin has provided its StormCrate55 modular crates for an underground attenuation tank designed to control stormwater and address excessive rainwater run-off as part of a prestigious development of homes in central Scotland. VAT) £70. Being experts in Sewage Treatment & Septic Tank Installations, we’re confident we can provide a solution that will last! Enquire Now. An attenuation tank can be made up of geo-cellular crates, impermeable geomembrane and protective geotextile, to create a watertight storage tank underground. The stored rainwater can then be slowly released into the sewer system, reducing the risk of flash floods. Delivery. 54 Excl. Innovators in water technology. The system was created using stormwater attenuation crates, which offer an economical and versatile solution to stormwater management. All the crates are doing is creating a large void underground. StormTech offers a cost-effective solution for stormwater attenuation by including a FREE integrated water quality treatment system. While digging the hole, look out for changes in soil characteristics at different. The crates are a single piece and. com : CORE Water | Soakaway Crates | Attenuation, Infiltration, Stormwater. By sgs. How To Install A Stormwater Attenuation Tank. Pipe Connections. As we can see, these tanks are named generally according to their application, for example, we name it rainwater infiltration tank when we use it as a. 5%) 0. 38 m³. 62’ x 1. Ideal for retention, attenuation or soakaway applications with a suitable geomembrane or geotextile. Contact us at: 1300 765 226 (Australia) +61 2 4747 4000 (Export) sales@acoaus. 18 Only full units should be used. storm crates, attenuation tanks, soakaway lagoons etc. 8x images & text from inside cover of SWM display box . 2. This provides both unit to unitunderground stormwater storage facility, for the application of stormwater attenuation or infiltration. • Load bearing strength of 62 tonnes per m3 • 95% void ratio • 100% recyclableAbout RecoCrate soakaway crates. 5kg. G 015 001 - RainSmart Stormwater Modules Datasheet NZ. In terms of maintenance, there is virtually nothing you can do as they should be buried at least 500mm down and may well have a substantial layer. Maximum installation depth of. From £3,669. It can hold 0. Rain Bloc Stormwater Attenuation/Soakaway Crate. ABG blueroof – Blue Roof System. Price on Application. Stormwater Retention, Attenuation. 00 10,000 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. 00 out of 5. Documentation. It allows rainwater run-off to be temporarily stored and then released gradually. we care for water. This is where stormwater is fed into the soakaway structure where it is held for long periods, allowing the water to slowly infiltrate into the surrounding soil, removing the need for stormwater drains and at the same time recharging the natural levels of groundwater. The void created by the storm crates can then fil up in heavy rainfall and let the. Stormwater Retention, Attenuation and Infiltration The Polypipe Polystorm Cells can be mainly used for rainwater Retention, Attenuation, Infiltration. has partnered up with a number of UK manufacturers. The Q-Bic Plus system can be used either as a temporary storage attenuation tank or a soakaway crate, particularly where accessibility into the tank is required. Variobox attenuation systems for stormwater retention are the strongest available. They allow surface water to be stored in one location and gradually released back to the ground, a bit at a time, at a pace the ground can handle, rather than in one sudden deluge, as happens during a storm. What sets this Polystorm Crate apart is its efficient interlocking mechanism. The unique compressive properties, modular design and choice of strengths, from 200kN/m2 up to 1000kN/m2, make GEOlight® extremely versatile. The system was created using stormwater attenuation crates, which offer an economical and versatile solution to stormwater management. Rain Bloc Stormwater Attenuation/Soakaway Crate. Experts recommend that the bedrock should not be within one metre of the drainage piping, in order to maintain proper filtration levels. This is independently tested and validated by NJCAT/NJDEP to. Flexible shape, perfect for use in restricted areas, narrow strips or shallow excavation systems. From £269. They provide an eco-friendly approach to control flooding and ensure the long-term sustainability of urban areas. Used as a soakaway the rainwater collected through pipes from the roof and/orThe StormGuard+ stormwater retention system has been engineered to enhance efficiency in infiltration, retention, and attenuation systems. Stormwater attenuation tanks provide a storage system for rainwater & surface water. StormCrate55 modular cellular crates are used in storm water retention, attenuation and infiltration applications. The Infiltrator ® Chamber is a pre-manufactured open underground unit that acts as a direct replacement for conventional storm water and waste water attenuation. 2m3 and 12m x 37m x 0. Each soakaway crate is a different size, therefore the brand you choose can determine the number of crates required for your attenuation system. AquaCrate Stormwater Soakaway and Attenuation Crate 20 Tonne - 2. From £269. Stormwater attenuation lagoons/detention. This below ground Rain Bloc crate is a simple an effective way to form a Soakaway or attenuation tank. From £3,669. You should receive some clips or ties with the crates. • Cellular stormwater crate • 4 crates per 1m³ storage capacity • Lightweight and easy to install • High strength crate with lo ad bearing of 562kN per m² • Each crate can store up to 237. We will look at the engineer’s design and optimise the tank depth to be as economical as possible for the contractor, even where there is a very shallow fall, or perhaps where we need to achieve. StormCrates are modular geocellular units which are used predominantly as below ground storm water attenuation, surface water infiltration and soakaway systems. Stormwater crates are installed below ground and are used to control the flow of surface water when there is extreme rainfall. -It has two main functions: “rainwater harvesting” and “rainwater utilization”. The crates are a single piece and can be easily maneuvered, stacked and placed. of Stormwater Attenuation Tank - Attenuation Crates for. The system is comprised of base plates, crates and side. Sustainable Drainage Systems (SuDS) have revolutionized the way we manage stormwater runoff in new developments. Please get in contact – 0121 351 3230. Delivery. ABOUT. ATTENUATION TANK CRATES FOR STORMWATER MANAGEMENT. The contribution of such systems to the carbon footprint of towns and neighbourhoods is largely unknown. As such, it’s an attractive alternative to crates, pipes and vaulted systems with numerous benefits. Features & Benefits: Formpave Distribution Tank Single - 354 x 708 x 150mm. The crates are ideal for soakaways and attenuation tanks specified by planning and building control. Each unit of Rainstore 3 measures 1 m x 1 m x 0. Stormwater is the excess rainwater that flows from rooftops, roads, car parks and other buildings. 19m3 per crate. The crates are designed to be simply and easily stacked together to create a below ground storm water holding tank or to allow the infiltration of storm water into the ground around them. 00 10,000 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. 1. Flexible connection options – length and crossways; DN 100 (4")/120 (5")/150 (6")/200 (8") 7. 3 Crates per m3, 60 Tonne Rated. 0m x 0. This Brett Martin StormCrate55 is a modular cellar crate system designed to be used as attenuation cells or for soakaway applications. Figure 4: Dimensions of Attenuation Crate Used (Water Management Solutions: Modular Cell Systems, 2011) tanks have land usage implications and this is not ideal in an urban envi-ronment. £69. Stormwater Attenuation & Soakaway Crates Construction projects, particularly involving stormwater management, are often impacted by concerns for the environment and new legislation. com or call us on +44 (0) 1296 633033you can reduce the number of attenuation crates/tanks used. Attenuation Storage Tanks - Multifunctional Benefits. Flood prevention infrastructure, comprising tanks or crates, are now installed into all new commercial developments. It is important to note that the proper installation, design and maintenance are essential to ensure attenuation tanks effectively provide the intended benefits. Allied to SDS SYMBiotIC™ smart monitoring and control these devices protect nature-based solutions from the impacts of. Buried with 0. 00. 00 Graf Infiltration Tunnel Kit for Soakaways, Attenuation and Wastewaster. Designed for landscaped, pedestrian or other non-loaded applications. While conventional SuDS systems, such as tanks, crates, and ponds, have been the go-to. 00 10,000 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. Iplex Aquacell® is a stormwater management cell designed for use in infiltration, attenuation or storage / reuse applications. 5m of cover for non vehicular or 0. Designed to support SuDS management and the sewer infrastructure as part of a designed attenuation system, helping prevent flooding by controlling the flow into the main sewerStormwater management system with various applications, Lorry-bearing 60 tonnes/HS-20, 410 m³ (14. Recyclable. £49. How GRAF stacks up vs. (1) From £ 0. Find a stockist. 0+. What are soakaway crates/attenuation tanks? Soakaway crates, also known as. Four StormCrates per 1m³; 95% void ratioHere at Drainage Superstore, we have a number of soakaway crates to choose from. Min Order: 2000. Description. Reels. Surface water drain pipes normally discharge to a watercourse or indirectly into the groundwater via a soakaway. What sets this Polystorm Crate apart is its efficient interlocking mechanism. Features & Benefits: Graf Rain Bloc Stormwater Attenuation Crate - 3. We're an underground modular stormwater infiltration & attenuation tank system China factory,our stormwater modular tank is for building underground stormwater infiltration, attenuation systems. The mounting plate inside is included but you will need a bespoke vortex unit - please ring 0121 351 3230 for price on Vortex Flow Control Unit. 00. The StormHarvester Active Attenuation system works by continually. Stormwater Attenuation Tank, Geocellular Storage Crates Supplier, Stormwater. Attenuation crates, also known as soakaway crates, are used to control the level of surface water and reduce the risk of flooding. Rain Bloc Stormwater Attenuation/Soakaway Crate. 00 10,000 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. The current perception is that roof runoff is. They plan an important role in protecting people, property, and local land from the build-up of rainwater during heavy downfall periods and can be used. Stormwater attenuation and infiltration/soakaway crates ACO StormBrixx is a unique and patented plastic geocellular stormwater management system for attenuation and soakaway (infiltration) usage. We supply 20 tonne crates for pedestrian traffic and all the way up to 100 tonne crates for HGVs and heavy plant traffic. This is. 3 crates per m3 gross volume). Crate size 1200mm (L) x 600mm (W) x 420mm (D) (3. • ACO StormBrixx soakaway crates: 2. 1000 x 1000 x 400mm (0. 50. Stormwater Detention Tank Crates is also known as stormwater infiltration tank, and it also can be named as rainwater modular tank, stormwater attenuation crates, stormwater detention tank or rainwater retention tank, etc. Stormwater attenuation crates offer good flexibility as they can be stacked and most come with a void ratio of at least 90%, which helps to reduce any wastage of underground space. Features & Benefits: Storage capacity of 290 litres. Designed for quick installation and boasting 100% inspectability, its adaptable modular design allows for customization according to projects, making it particularly suitable for landscaped areas and. For More Information Please Contact Stormwater’s Technical Office On: Tel: 01455 502222 Fax: 01455 502223 Email: sales@storm. It can hold 0. This looks at legislation and key criteria for geocellular crates, including ACO StormBrixx, as. We can also offer an installation service if required. Lightweight and simple to install. Attenuate or infiltrate surface water and stormwater effectively even in challenging high-traffic urban environments. Cut outs are available for incoming pipework. The full Rainbloc attenuation tank kit can be found here. All developments of scale, now have to contain their stormwater on site and slowly release it to the drainage network, at a controlled rate. uk 3. • Polypipe Polystorm soakaway. What are Attenuation Tank Crates? Attenuation Tank Crates are containers designed for the storage of rainwater. 5m of cover for non vehicular or 0. These strong, long lasting and eco-friendly crates are ideal for use in residential, commercial, industrial or retail areas including car parks. Reviews. Call us: HOME. Specifications of our systems. From £269. Size: 3. Torwood Glen. Stormwater Attenuation Crates I Stormwater Attenuation Tanks I Stormwater Attenuation Lagoons. 82’ (800 x 490 x 250mm) Material: 100% Recycled PP, or Virgin MaterialsThe crates are also pre-fabricated and fully assembled, making them ready to use and be installed straight away. 6m x 0. Stormwater Management Ltd was able to find a solution for a domestic, localised flooding issue, which was resolved with minimum costs and disruption to a residents house. 5m x 0. The runoff comes from car parking areas, golf courses, racecourses, as well as sports fields. 5m below the surface connections of any diameter can be made to the system. 0121 351 3230. C&L provide stormwater attenuation products from Polypipe and Wavin. Product Description. 27-29 High Street, Drayton, Abingdon, Oxfordshire OX14 4JW, England. Key Benefits of the PSM1A Polystorm-R Crate: Suitable for both attenuation and soakaway systems; 100% Recyclable; Only 4 StormCrates per 1m³; Load bearing strength of. Attenuation systems are large storage facilities included in a drainage system so that rainfall from storm events can be stored onsite and slowly discharged instead of discharging the whole storm event as it happens. StormCrate is a cellular stormwater attenuation crate. It’s the fact that they’re wrapped and sealed in a completely watertight liner that they actually perform a job. competitors. Based in the Midlands, we're specialist installers of stormwater attenuation systems, incl. 00 Graf Infiltration Tunnel Kit for Soakaways, Attenuation and Wastewaster. APPLICATIONS • Landscaped areas11. £69. The void created by the crates can then fill up with storm water during heavy rainfall conditions. To get started with the AquaCell Configurator, you'll need the following: The address and postcode of the site. 5 yrs CN Supplier . Residential developments. Applications. They are modular, so multiple crates can be used for a soakaway. SDS GEOlight® is widely recognised as the UK’s market leading water storage and attenuation / infiltration system. The crates are designed to be simply and easily stacked together to create a below ground storm water holding tank or to allow the infiltration of storm water into the ground around them. Shows. 0m3 of storage volume!The JFC OriChamber is a prefabricated unit which comprises a Ø600mm Twinwall Chamber with base, 110mm internal and outlet pipework and a pedestrian duty (bolt down) cover. To build the attenuation system, the blocks are connected together into a matrix. Our RecoCrate range of soakaway crates are lightweight modular cells with a high void ratiowhich can be used for creating underground water storage systems and attenuation systems for landscaped areas. Soakaway Crates are quick & simple to install and a variety of size. (€4,213. These soakaway crates (Polystorm) clip together to form a load-bearing underground water storage/attenuation system. Our range of Soakaway Crates include the Polypipe Polystorm, Polypipe Polystorm Lite, Aqua Storm and the Brett Martin StormCrate. When calculating the size of the area that needs excavating, remember to allow extra width, length and depth for a base, side and backfill. Image of a stormwater attenuation tank from the top. Ever wondered how we install our stormwater attenuation systems? Check out this video of an installation we did down in Bristol! Video. Used in landscaped areas, or in trafficked areas up to a Gross Vehicle Weight (GVW) of 30 tonnes. Features & Benefits . Rated 5. They are modular, so multiple crates can be used for a. 28′ x 1. 00 Graf Infiltration Tunnel Kit for Soakaways, Attenuation and Wastewaster. 00 15,000 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. e. Most systems comprise some sort of holding area, often an underground tank, that fills up during a storm. Benefits of Using. The crates are a single piece and can be easily maneuvered, stacked and placed. 5 Per m3. Extensive use of this type of storm water attenuation module has helped relieve pressure on conventional surface water drainage systems in line with the Sustainable Urban Drainage Systems (SUDS) program advocated by the Environment Agency. VAT. 5 crates to provide 1. Stackable stormwater attenuation crates offer a modular design that give you more flexibility over how the system is installed and set-up in the ground. Flexible design. Leiyuan - Model M2015S - Infiltration Tank - Geocellular, for Underground Stormwater. Reduce the risk of flooding and its consequences by providing for better, more comprehensive and co-ordinated water management. 00. An impermeable geomembrane liner is then installed and the attenuation crates are positioned inside that. Brett Martins stormcrates are modular geocelluar units which are used for storm water attenuation surface water filtration and soakaways . The StormCrates are designed to be stacked together to create a. 00 7,500 litre SuDS Rainwater Attenuation Tank with. Lightweight recycled polypropylene structure. This should give you a total impermeable area in. Head office: 134-140 Old Bathurst Road Emu Plains NSW 2750 Australia. 19m3 per crate. 5L per crate. S. As the crate structure fills, water begins to exfiltrate from the tank into the surrounding ground. Complete crate weighs 9kg. Comment. £54. The compression fit units are stacked (if applicable) and sent preassembled to the construction site so there is no assembly required. The Brett Martin Stormcrate 55T Soakaway Crate is the perfect solution for managing stormwater runoff. 4m3 per crate. Properly containing sediments, contaminants, and surface runoff is essential to meeting environmental regulations and creating world-class. The stored water is then released once the flow has decreased, ultimately maintain control of the amount of water in the ground, keeping it at. Soakaway crates (also known as storm crates, infiltration crates, anti-flooding blocks or attenuation crates) have an integral part to play in the prevention and reduction of surface water flooding in built up areas. Specialists in water management & treatment. 354mm in length, 708mm in width, 150mm in height. With its dimensions of 1200mm x 600mm x 347mm, it can hold up to 0. Attenuation Design. stormwater management. Largest range of Soakaway Crates and Attenuation Cells for Drainage in the UK. Find Technical Info See Polystorm in action here. £54. 00 incl VAT. Stormwater Attenuation Tank. Doctor Rain is the leading manufacturer for stormwater attenuation crate in China, our production capacity reach 1500m3 per day. ACO stormwater tanks provide an innovative tree pit solution. They are versatile products that can be used under car parks, landscaped areas and heavy duty projects within residential, retail, commercial and industrial areas. These crates are used in a storm water management system to provide temporary storage for rainwater runoff. 5 crates required per cubic metre (1m3) 200 kN/m2 compressive strength (Domestic Duty) Maintenance free - silt removed before crate using geotextile fabric; Light weight and easy to handleEst. StormMaster is an innovative company specialising in underground infiltration and attenuation tanks in connection with sustainable urban drainage (SUDs) schemes. 5m x 0. Triton Stormwater Solutions: The Comprehensive, Low-Maintenance Underground Stormwater Solution. £69. Cheap prices & extremely fast shipping guaranteed. Go deeper with Polystorm Deep. 00. indd Created Date: 10/16/2023 11:03:26 AM. KLARGESTER AQUAHOLD SM05 - 5,000 litres. What is a stormwater attenuation tank? A stormwater attenuation tank allows for surface and rainwater storage, which can be a requirement when new housing, commercial developments or car parks are built. Stackable stormwater attenuation crates offer a modular design that give you more flexibility over how the system is installed and set-up in the ground. Customers we have served. The installation is warrantied for 30 years as the membrane is wedge welded and the joints air tested. The honeycomb design is extremely strong allowing. Explore. Easy installation, monitoring, and maintenance. 00 Graf Infiltration Tunnel Kit for Soakaways, Attenuation and Wastewaster. Take water infiltration into your own hands with our reliable and durable soakaway drainage solutions. 5kg/tank Stormwater Drainage Attenuation Systems Stormwater Drainage Attenuation Systems refers that. Crate Size: 1. This product can bear up to 65 tonnes and is 1m x 0. The UK's highest rated online drainage & pipework supplier; Email 01371850120; EmailEcomerchant Aquacrate is designed for the storage (attenuation) of stormwater in both attenuation and infiltration schemes. 3 StormCrates per 1m³ storage capacity • Lightweight and easy to install in up to 10 layers • High strength crate with lorry bearing of up to 60 tonnesCarlow Concrete are one of the leading specialists in Stormwater Attenuation in both the UK and Ireland. The system facilitates quick and easy assembly on site where multiple configurations can be formed. The RainSmart® modular tank system is suited for subsurface infiltration, retention and detention stormwater applications. Iplex Aquacell® is a stormwater management cell designed for use in infiltration, attenuation or storage / reuse applications. An offline attenuation system is where the inlet/outlet is connected to the same manhole/inspection chamber. The crates interlock to create a substantial below-ground holding chamber or to facilitate stormwater infiltration into the adjoining earth. If using Aquacrate 400's you will only require 2. 3 Crates = 0. The soakaway crates have various load ratings that indicate their storage capacity. Stormwater Management Brett Martin’s StormCrate55 modular cellular crates are used in storm water retention, attenuation and infiltration applications. This Brett Martin StormCrate55 is a modular cellar crate system designed to be used as attenuation cells or for soakaway applications. With its dimensions of 1200mm x 600mm x 347mm, it can hold up to 0. Consequently these systems can be installed under car parks and access roads as well as landscaped areas. Choosing a stormwater attenuation tank size. VAT – +. Other factors to take into consideration include the expected flow rate and the type of soil in the ground. Stage 2 - The filtered stormwater enters the pre-built geocellular crate system at a size that will hold the required level of stormwater.