Protecting property. 0m can become difficult and more expensive to build. Chapter 3 19948. The Soakaway Design Guide (July 2000) 2. If compacting is inevitable, the next best thing is to amend the soil with compost, gypsum, wood chunks, and mulch. it may mean deeper than standard foundations particularly if you have clay soil. It strengthens root anchorage. Soakaways and alternatives. Does a soakaway need emptying?The result is a reduced performance of the septic system, or even system failure, which can cause effluent to pool on the surface. connect condensate discharge pipe to the soil pipe or mains drainage. Free call for quote on. Work the compost into the soil down to the top six inches to one foot by hand with a garden fork or a spade, or you can use a tiller. allow the garden. The second most important factor is the soil type - its condition and permeability - of where you would be installing the soakaway crates. Has anyone any plans for a soak-away. WaterloggedThe Ground Conditions and soil type. All options must be lined with a filter cloth with a mass per unit area of 140 grams/m² and a minimum thickness of 0. To work, it must extend below the clay and be at least 1. Consequently,can you have a soakaway in clay soil? The excavation for the soakaway is usually done by mechanical diggers. Usually comes as a kit and The hole can be anywhere from 600mm to 1 metre deep and about 200mm in diameter. The SOAK1GR should only be used in porous soil. I know we have a lot of rain lately, but the garden is. Beg some plastic milk or beer bottle crates, wire them together to form a cube, wrap it in horticultural ground cover fabric and bury it in a pit, running a rainwater pipe from the middle of the crates to the outlet of the drainage channel. As sodium salts are leached through the soil, some sodium remains bound to clay particles—displacing other cations. Hiya We noticed a lot of standing water after moderate rainfall in the centre of the garden so I lifted the patio flags and it was sitting water on quite heavy clay soil/builders sand mixture. 2m x 1. To work, it must extend below the clay and be at least 1. To construct a basic stand alone soak away or one to use as a dispersal point for a French drain system where the water will gradually seep away into the surrounding soil. Dig a hole 300mm square to a depth 300mm below the proposed invert level of the incoming pipe. Start by digging the standard 1m x 1m x 1m trench, increasing the size if necessary,. The soakaway must be a minimum of; 5m away from your building 5m away from a road 2. When is a soakaway possible? A soakaway is possible when: The ground infiltration rate is greater than 1×10-6m/s. As discussed above, septic tanks use a filtration system to seperate the solid waste from the liquid wastewater. Fit a plastic underground drainage pipe from the drainage channel or rainwater pipe into your soakaway, and attach a gully trap at the top end of the pipe. In poorly structured soils (heavy clay soils), effluent ponding may occur reducing the soil efficiency in treating and retaining STE. A soakaway can be left open, filled with small stone or river rock, or filled with rock and then covered with a layer of sod or soil. If you are hoping to create a soakaway to alleviate waterlogging in a garden, you may well be disappointed by what follows. . Thread starter Temmy; Start date 20 Aug 2021; Temmy. clay or rock). We have a house which has a slope running down towards the front. The type of sediments likely to enter the soakaway depends on the. Vermiculite is good for root growth. Most of the time the soakaway will be one metre cubed and hence 1 metre tall. However, if digging is just too hard on your back, using a tiller is a fine method. Oliver W. After (just recently) reading to manufactures instructions concerning the soakaway its states it need needs to be. Typically developments situated on soils with a high clay content tend not to be. Water in camps of Displaced people 1994. Due to its nature, vermiculite prevents mould. The Infiltration Rate of Soils also tends to decrease over time. Clay soils typically do not drain very well and can in some cases be impermeable. 5m away from the garden wall). Back Garden Soakaway + Clay. This can cause the soil to shrink, especially if it is predominantly clay, which has consequences for structures built on it. ) Organic materials like compost are recommended for amending clay soils. Done properly, there will be no visible signs that any work was carried out. Reaction score. Your soakaway should be at least one cubic metre, and be below the bottom of the feeder pipe. A soakaway system is an online system whereby all storm water flows into the crate structure and infiltrates into the surrounding ground as and when saturation allows, until the crate structure is completely empty. This can sometimes be the case for soakaways installed in silty or clay soils. Dig a series of parallel trenches every 3-6m across the garden, sloping towards the ditch or soakaway. In many cases, sites with a high water table or a heavy clay content will also not be suitable. ALL parts of the soakaway drainage field are required to be a minimum of: 10m from a watercourse or ditch. Country. See full list on gardendoctor. As a broad brush a Soakaway Size of 1m³ is sufficient to drain a roof area of approximately 50 square metres under normal conditions. The percolation test method. See more of Septic Tank Soakaway Kit on Facebook. We have heavy clay soil so the soakaway gets full and floods in heavy rain. We are on clay soil but there is no combined or rainwater drainage in the road. The presence of clay and silt within sands and gravels can severely impact the permeability of the soil – a complication often not considered if the majority of the soil is permeable. Alternately, gardeners can build berms in the landscape to lift plants out of poor-draining clay. Robust, durable and easy to handle. 45 mm. The best garden drainage solutions usually consist of a french drain system leading into a pump station which redirects water into a surface drain. The organic matter needs to be mixed into the top 6 to 12 inches of soil. I started to dig a soakaway pit, only to find four different colours of clay. We considered zero tillage (no-till) as compared to conventional tillage, cover cropping or green manure practices that keep soils covered compared to leaving them bare (cover crops),. Digging in a french drain with perforated pipe along the side of the garden. To work, it must extend below the clay and be at least 1. Step 2. Accommodates between 4 to 25 people. Beauty Advent calendars for 2023 incl M&S £348 for £45 (+£35 spend), £200+ of No7 for £43, £100 of Ciaté for £19. Clay and clay-based soils have poor porosity: it is impossible to disperse the septic system effluent satisfactorily in such non-porous grounds. If using proprietary compost mixtures, follow the instructions on the package carefully. Follow these 6 simple steps to install soakaway crates – both quickly and correctly: Step 1 – Create space. Rainwater harvesting systems will usually have an overflow to a soakaway or drain. It is based on the principle of a “reverse well”, which collects and drains the water rather than holding it. Freeman II, in Advances in Agronomy, 2019 3. In these circumstances a specialist software package is usually used, such as. Soakaways in impermeable soils are unlikely to function because they just fill up with water, so an alternative method of disposal is required. As a result the risk of water affecting the soils Soakaway systems are a commonly relied on solution for dealing with standing surface water, as they enable you to channel rainwater from your drainage system into buried soakaway As a result, it’s generally not recommended for use in leach fields. So yes soakaways can work perfectly well in clay. if your ground is relatively free draining then building control will insist upon a soakaway if practical. This, as well as some other planning around your soakaway construction, will make the job much easier for you – preventing a mistake that could be time-consuming to remedy. When designing a leach field for clay soils, it’s important to take several factors into consideration, including the soil’s texture, structure, and drainage capabilities. However, using cement and lime has become one of the main concerns for engineers because they negatively affect the environment and economy,. It consists of a hole dug into the ground and filled with rubble or coarse stone with a drainage pipe or French drain running into it. One is to run your rainwater into a water. 29 Apr 2020. If the water clears within half an hour, you have adequate amounts of gypsum. Septic Tank Maintenance. 1. A premium blend of fine soil improver and composted manure, perfect for putting life back into tired, heavy or light soils. how quickly the water will soak into the soil around the soakaway. Dig a series of parallel trenches every 3-6m across the garden, sloping towards the ditch or soakaway. At 1. The following images show failed soakaway tests the 1st in a heavy clay soil and the 2nd in low lying ground next to a river with the water table lying more or less at surface. I'd have thought once you removed all the top soil and roots etc down to the sub soil and get 100+ mm of well compacted hardcore, it doesn't matter how soft the underneath is. However, the groundworks have revealed that the site is almost all heavy clay and shale. Reply OP Posts Only. Dig Out the SiteDig out a 600mm x 600mm patch of ground, about 3-4 inch below the height of your grass. Kent. When water hits the channel drain, it's sent off in another direction, well. The two determining factors. The porosity is so bad that they often fail within the first 5 years as their air spaces become filled with the high levels of suspended solids, often above. Before checking the soil or inspecting the land you must check local planning regulations, especially if you’re including the soakaway as part of an addition or extension to your. The size of the soak away will need to be worked out in advance. White clover spreads horizontally and grows 4-8 inches tall. Drainage trenches can be particularly useful in clay soils which are easily compacted. 2) and the highest in algae (pH ≈ 9. Where the new driveway is small, if the existing garden is not water logged it should be acceptable to allow the water to soak into the ground. Heavy clay soils, like black cotton soils and soils prone to surface sealing, hold moisture for long periods, meaning they become waterlogged easily. #15. If the septic tank isn’t emptied regularly enough. Growing tree roots interfere with pipes in the system,. Put 2cm of soil in a large jar filled with water, screw on the lid and shake. Chapter 3 1994 8. How deep should a soakaway be in clay soil? 1. Clear gutters and outside drains. Gypsum is calcium sulphate and is touted as very beneficial for breaking up compact clay soils. Country. by. It should be noted that soakaways rarely work on heavy clay soils. You may be able to discharge the water into a sewer if no other alternative exists and you have permission from the water company. You should place an impervious layer on top of the. When installed correctly, French drains can redirect water to a designated location, such as a soakaway. Fill the drains with wrapped gravel. dustmaker said: building regulations state that a new soak a way has to be at least 5. If the ground is unsuitable, like clay soils are, localised flooding can occur due to waterlogging. And it could be right if we consider that concrete has sand in it. Installing a soakaway provides a means by which rainwater from a building can be collected and dispersed into the soil in a suitable location. Pre fabricated soakaway and trench baskets. These fibers are an excellent material since they help orchids grow strong roots that can hold the plant together. Clay is extremely dense and there aren’t large enough gaps between the particles in the soil to allow liquid to pass through. The pre-fabricated soakaway system offers an alternative to gravel when installing a French drain garden drainage system. This study investigated two types of biopolymers as alternative soil. 3. A soakaway is a common drainage solution for many properties in the UK. Rainwater harvesting systems will usually have an overflow to a soakaway or drain. The first method is to dig up the soakaway, remove all the pipes and crates and re-install a new system. However, the consolidation of the soils is time dependent, delaying construction projects making it a non-feasible alternative. In contrast, clay soils and hard-packed or rocky soils are. Top tips to reduce surface water flooding. It is worth mentioning that certain soil types like heavy clay will be unlikely to allow sufficient water drainage for a soakaway, while sand, chalk and limestone based soils are likely to be suitable. filled the hole at 1820, and by 2217 it had possibly (possibly) moved 2cm, but I suspect thats more hope than anything. 9. 1. Simple to install, with minimum maintenance required. The side drains join the main drain at a 45 degrees angle and are spaced at 10 ft intervals for clay soil and 25 ft intervals for loamy soil. 8m deep. In a word, peat is springy. Break up the earth at the base of the pit with a garden fork. T. Sunday 9th August 2015. The insides of the excavation can become smeared, particularly by mechanical diggers building a soakaway in clay soils. Once connected, they allow water to run off your roof, into your downpipes, and down into the underground soakwell allowing the water to seep away into the surrounding soil without causing any damage to your property. A soakaway is a simple way of dispersing surface water when a connection to a surface water system, such as a gutter down pipe, is unpractical or isn’t possible. This pit is then filled with coarse gravel, rubble or even plastic crates that allow the water to collect and filter through. Generally a soakaway built on non clay soil to take and disperse water from a gravel French drain system draining a 120 m2. Plan patios, paths and decks. Settlement of the Made Ground could result in settlement of the inlet pipe into the soakaway, opening of joints and water leakage. The size of the soak away will need to be worked out in advance. If a soakaway is impossible to achieve, you may be able to discharge the water into a local watercourse if you live next to one. This is a low fired clay product used to clean up spills. 5m and 7. 3. Creeping thyme in high traffic areas. In addition, gravel helps to provide stability, reducing issues such as erosion. The purpose of a soakaway is to discharge and percolate the water back into the soil at a steady rate – preventing downstream flooding. NB: Due to size constraints, developments in urban areas are sometimes not large enough to use a soakaway. The soils treated are Organic silt, Varved silts and clays, soft clay, Dredged material The design considerations which should be made are bearing capacity, Slope stability, Degree of consolidation. Save time and money with the soakaway experts. (The garden is about 3 foot higher than the extension's dampcourse) Its clear that any soakaway. When rainwater floods into the same area time and again, a little light geoengineering may be the solution. The SOAK1GR should be sited as close as possible to the boiler but clear of the building foundations and not in the vicinity of other services, such as gas, electricity or water connections. Fill with water to depth of 300mm. e. Appears that a normal soakaway is out of the question, unless its going to be huge, then it would just be an underground water storage facility. I'd like some insights on how to handle the grey water coming from my building. Practical Ways to Improve Clay Soil for Your Garden. Other clay soils will achieve a low infiltration rate which makes a rainwater. Dig a series of parallel trenches every 3-6m across the garden, sloping towards the ditch or soakaway. Ideally you prefer a soakaway rate of 1 x 10-5m/s in order to achieve the half emptying time1. the back garden is on a slight slope towards the house, so they said this would remedy the problem. Here are the steps required for undertaking a percolation test for foul water soakaways: Excavate a hole – Dig a hole 300mm square to a depth of at least 300mm below the proposed invert, spacing them along the proposed line of the where the soakaway would be. Generally a soakaway built on non clay soil to take and disperse water from a gravel French drain system draining a 120 m2. Soakaway crates · June 30, 2020 · · June 30, 2020 ·newcastle phill. The down pipe (cast iron) appears to be blocked and the water is filling back up the down pipe and gushing out at the lowest joint which is about 4ft from the floor and subsequently soaking the walls of. The soil in which the soakaway is placed must be granular with good drainage properties. Whereas if the soil is very sandy with a high infiltration rate, you can install a small soakaway. #2. How build a soakaway using soakaway crates. A soakaway crate is used as part of a full drainage system in areas that experience high levels of surface water or run-off. Soakaway: A soakaway is an underground structure designed to disperse water into the surrounding soil. In doing so, it will add to its ease of cultivation. Discussion. 1. Allow the top of the soil in the pot to protrude 1 inch above the soil line. This is done to guarantee that the ground (soil) is suitable for a soak away, as well as that the soak away is correctly built for the situation at hand. Some soils, such as heavy clay soils, will not work with this kind of drainage. As an aid, mark a stick 300mm from one end, place in the hole and fill up to the mark. In our first spring season, we noticed the garden was very waterlogged and pestered the builder who eventually installed a soakaway in the garden approx 1 metre from the back of the house. andrew hall, sumdog; kurt angle rap battle lyrics; miami herald press release submissionAdditionally, you should carry out a soil percolation test to determine whether the soil on your property is appropriate for a soakaway drainage system. How to Build a Soakaway in Clay Soil? A soakaway is basically a deep hole filled with rubble. 28 Mar 2008. Swale. 4) Dig up the entire garden and mix the soil. 2m deep it's still surrounded by clay and after yesterday's heavy rainfall this is what it now looks like:soakaway to be considered. These types of soakaway are useful where a very good infiltration medium underlies a deep layer of poor infiltration material, such as gravels underlying a deep. The fitter assured us that it was all done correctly and that it has been fitted into a soakaway. 24” diameter x 28. Many recently developed neighborhoods, especially in Eastern Nebraska,have had their topsoil removed and. Add water into bucket around sealed clay bag; no need to submerge top of bag. They consist of a perforated pipe surrounded by gravel to facilitate water movement. it may mean deeper than standard foundations particularly if you have clay soil. Mix the perlite into the soil you already loosened. You need to find out from the BCO if he is requiring you to connect to the surface water drain before going any further. In clay soil, when the rainwater pools on a specific area, dry wells can solve that. This. If the sediments entering the soakaway are the same size or larger than the pores in the infiltration medium then the sediments do not significantly affect the infiltration rate through the soakaway. (Prior to the extension the rain water on our old conservatory was going straight into the public sewer. 5 litres to fill a volume of this size. If the water table is too high, then a soakaway simply won’t work there. If the water clears within half an hour, you have adequate amounts of gypsum. 24 30 1. Getting it emptied pronto might just prevent any permanent damage. Add a gradient. Gardeners with clay soils may choose to bring in an alternative soil and garden in raised bed boxes, or amend existing clay soil with loamy topsoil or well-compostedseptic tank soakaway clay soil - septic tank soakaway clay soil. 8m deep. 5 driveway drainage solutions for your front yard. This closes the pores and fissures at the excavation interface leading to. Procedure. I have a building which sits on top of clay ground so I couldn't soak away the grey water. Backfill the hole so the crates are secured. Soakaway not installed correctly. 7 Mar 2015. 5m deep in a lower part of your garden and preferably at the bottom of a slope. (Using a tiller too often will actually impair soil drainage by breaking up soil aggregates. Soakaways are no appropriate for polluted rainwater. V = the time in seconds for the water in the test hole to drop by 1mm. Get your septic tank or treatment plant emptied - ok, so this might be the only easy solution, but it might just do the job. Clay and rocky soils aren’t their cup of tea (ha). Pre-settled effluent from a collection and storage/treatment or (semi-) centralized treatment technology is discharged to the underground chamber from which it infiltrates into the surrounding soil. Country. #1. Be careful if you are using a rotavator, it's likely to bounce off the compacted clay until you get the hang of it. If you end up building a soakaway over or in heavy clay or clay soils, you’ll actually end up with a pond due to the non-porous properties of heavy clay and clay soils. 3. 0 views, 0 likes, 0 loves, 0 comments, 0 shares, Facebook Watch Videos from Soakaway Worms: septic tank soakaway clay soilDig a hole into the soil approximately 60cm (2 feet) deep; Fill the hole with water and leave it for four hours; If the water is still there after four hours, then it’s a good sign that you need drainage. Note that sometimes, especially after heavy rainfall, accumulated surface water may not drain as fast as usual. Step 3 – Prepare the base. septic tank soakaway clay soil - septic tank soakaway clay soilyour septic tank and soakaway in clay soil?Are you. in the soakaway. The insides of the excavation can become smeared, particularly by mechanical diggers building a soakaway in clay soils. If it is practical dig off the top soil, double dig incorporating the grit (I would avoid sand totally) and long manure. It's best to think of water pouring into a soakaway rapidly then slowly draining away into the surrounding soil. However, it’s a lot more subtle in terms of its appearance in the landscape. The most commonly used in the industry is: Soakaway Volume = Area x (Rainfall Rate/3000) For a standard 60m2 roof or driveway in the UK the calculation would be: 60m2 x (50mm/3000) = 1m3 volume This means you would require 5 of our CORE Water Crates to create a 1m3 soakaway. Log In. I've found that garden compost is best, but conditioners such as seaweed, farmyard manure, or bagged manure products like Scott's. If the water table is too high, then a soakaway simply won’t work there. Area (A) = V X P X 0. 1. Bore a hole 150mm in diameter with an auger, to a depth of one metre. 35 80 4. An online system. Garden or driveway soakaways are usually much smaller than. 1. For this purpose, soil (n = 2), “soakaway” sediment deposited in the artificial infiltration facilities (AIF) (n = 4), and road dust (n = 2) were sampled from Tokyo metropolitan. A rectangular grid allows alternative pathways. An online system. Let Geoinvestigate’s experts quote for your next SuDS soakaway, soakage, percolation, permeability or soil infiltration test. Step 3 – Prepare the base. septic tank soakaway in clay soilseptic tank and soakaway kit makes light work of clay soil. This material holds water very well and is easy to find at any local garden store. The slope of the apron (1%) should fall to a drainage channel leading to a soakaway pit, an irrigated garden or a cattle drinking trough (see corresponding briefs). 75 high. DON’T install a soakaway if you live in a polluted area prone to smog. How to Build a Soakaway in Clay Soil? A soakaway is basically a deep hole filled with rubble. Add 4 to 5 inches of coarse sand for every square foot of clay soil in your garden, and work it into the soil to a depth of at least 8 inches for the best effect. Start by digging a pit approximately 1. However, an increasingly popular soakaway solution is soakaway crates. During my internet forays I've come across the option of using rainwater crates instead of simply digging a hole, lining it and filling it with stones to form a soakaway. septic tank soakaway clay soil - septic tank soakaway. This. Step 2 – Prepare the crates. This means that if you build a soakaway or put crates into the ground it will just sit there or drain away very slowly. The condensate pipework may terminate above or below ground level. This year, for the first time in about 40 years my parents garden flooded. Save time and money with one of the UKs leading soakaway and site investigation experts. Soils with high clay content may have poor drainage capabilities compared to sandy or loamy soils. Usually we would recommend 10mm or 20mm pea shingle for this. In other words, 1 crate should be used for every 10-12m2 of. option 2. Once the back, side and top is covered with 150mm of pea shingle, then you can add the top soil – usually a minimum of 400mm. How a French Drain Works - in Clay Soil. Coarse Sand. Sodicity in soil is the presence of a high proportion of sodium ions relative to other cations. See more of Cesspit on Facebook. Why not take a look at our Horatio’s Garden drainage case study for more information. The soil particles in the soakaway area filter and treat any remaining waste in the water draining from the septic tank. Plus, a cut pool noodle can help to improve drainage in hydroponic systems. Coconut fiber. 8m deep. Therefore it is a concentrated point source of water in the ground and the height of these types of soakaways means that water also flows out sideways. Location. org If you are just interested in getting the water away from your clay soil and elsewhere, you can have it drain away from your property. The effects of applying fly ash for soil stabilization are the reduction in the plasticity and soil swell potential and increasing the soil strength and CBR values. Excavate the area, making a hole that is the right size for the crates and the top, side and base fillers of gravel and sand. Area (A) = V x P x 0. Vermiculite aerates soil well if used together. Furthermore, expanding clay soils with a COLE value greater than 0. How do you fix poor drainage in clay soil? Adding plenty of organic matter Soakaways will eventually silt up. Alternately, gardeners can build berms in the landscape to lift plants out of poor-draining clay. They can’t tolerate competition very well. Water-loving plants like swamp milkweed ( Asclepias incarnata; pictured) or cardinal flower ( Lobelia cardinalis) both beautify and improve poorly draining areas. In clay soil, the effectiveness of a. Based on. P = the maximum number of persons that the treatment system/tank is designed to serve. The ideal garden drainage solution depends on. Surface Water Drainage Options in Clay Soil Are soakaways suitable in clay soils? ©2023 by GeoSon. Ground where water soaks away too quickly (e. Allow winter frosts to work on clay and break it down. Note that land drainage is NOT the same as a soakaway, although they may both be used to dispose of surface and/or ground water. Be careful if you are using a rotavator, it's likely to bounce off the compacted clay until you get the hang of it. This option is super popular for crafty hydroponic gardeners on a budget. This includes the top and the bottom! If your soakaway is covered by soil or lawn you will need at least 200mm of topsoil on top. If the garden is already waterloggedAbove-ground mound soakaway systems, or mound systems, were developed by WTE Ltd. (c) Soil Investigation for Septic System Design & Installation Approval. 5 metres is just from the building in any direction, it doestn have to be away from the sides. The main aim of this study is to. Next, a long channel drain is placed in the trench. Accessories include cover, additional panels, bottom, surface drain and filter fabric. Here is a statement from Trent Water: Mound systems work well as alternatives to septic tanks when the soil around your home or building is too dense or too shallow or when the water table is too high. There's a slightly smaller soakaway out the back which we have joined into for the rear, all rear rainfall also goes via a 1250l water butt. The liquid is passed through a soakaway system and is discharged into a drainage field. Remember though, the water still needs to be able to escape. To do so, we’d recommend using sand or shingle material. To compensate for the lower structural support capacity of clay soils, permeable pavements often need greater subbase depth—which also adds storage volume to compensate for the lower infiltration rate of the clay subgrade. A traditional soakaway will have a ratio at the higher end of scale where it drains a road or several houses. Best garden drainage systems in a nutshell. Because of the poor porosity, soakaways frequently fail within the first 5 years of operation because the air gaps in the soakaways become clogged with the high amounts of suspended particles in the effluent, which. The rate of this silting depends on several factor but principally the following. Whether you’re using crates or stones for your soakaway pit, be careful not to spill soil inside your geotextile lining as it won’t work effectively. A deep bore soakaway is a special type of rainwater soakaway consisting of a conventional chamber and a narrow bore perforated liner extending to the infiltration medium. Step 6 – Replace any ground that was removed. Dig the test hole vertically to the proper depth. You can claim a ( small) reduction in your water bill. The purpose is to slow and control the flow of water to prevent flooding. DON’T install a soakaway in heavy clay soil, the water cannot drain through this so it won’t work if this is in your garden. DON'T install a soakaway in heavy clay soil, the water cannot drain through. No need to compact the bottom. To work, it must extend below the clay and be at least 1. Dig. Regrading the garden slightly to have the water run down to one side. If using dried seaweed meal, apply 100–200 grams per square meter. Dig a series of parallel trenches every 3-6m across the garden, sloping towards the ditch or soakaway. The test procedure is outlined here. Make it level. This is a more complex project, and. Kaolinite clay soil, with a chemical formula of Al2Si2O5 (OH)4, has a low shrink-swell ability and is. 8 meters deep to work. The pre-fabricated soakaway system offers an alternative to gravel when installing a French drain garden drainage system. orsoakaway to 50% surface wetting or the filling of effective depth: this excludes the base area which is assumed to clog with fine particles and become ineffective in the long-term; f = the soil infiltration rate determined in a trial pit at the site of the soakaway; D = the storm duration. For clay soils where the percolation tests are in the order of 2x10 7 (m/s infiltration rate) the following table can be used as the basis of soakaway design. . Crates measures 800x500x540mm = 0. Soakaways are used to manage surface water at its source, and serve as an alternative option to draining off surface water via a stream or sewer system. If it takes one to two hours for the.