If you are hoping to create a soakaway to alleviate waterlogging in a garden, you may well be disappointed by what follows. this has lead to storm and in some cases sewer drains being overwhelmed. The condensate pipe should discharge into a purpose made recepticle and the bottom of. Soils with high clay content may have poor drainage capabilities compared to sandy or loamy soils. 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. Soakaway problems have a range of causes, many of which can be hard to diagnose without thorough investigation, training and. Ensures no contamination of ground water. Calcium-based binders, such as ordinary Portland cement (OPC) and lime (CaO), are the most common artificial cementitious materials used worldwide for concrete and soil improvement. 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. See more of Septic tank installation cost on Facebook. Do not use fine-grained sand as it will just. Digging with a sturdy spade is the best way, but using a rotavator works OK too. Tin Soldier; 13 Feb 2017; Building; 2. Full drainage design suite (50% Discount) including 7 spreadsheets; Soakaways built in Clay Soils need to be carefully designed in order to operate effectively due to the low infiltration rate of most clay soils. A soakaway is essentially a point feature; it does not have a channel. Water in camps of Displaced people 1994. Allow the top of the soil in the pot to protrude 1 inch above the soil line. changed your discharge from surface water to ground. If the garden is already waterloggedNormal soakaway drainfields will not be able to soak wastewater away into clay or clay-based soils because of their porous nature. The guttering had been disconnected. clay or rock). Peat Moss. A soakaway system enables you to collect water and then slowly disperse it into nearby soil without creating excessive runoff and overwhelming the underground drainage systems, which is particularly important in areas with higher than average rainfall, hard ground or steep sloping ground. Refill the hole and time how long the water takes to seep away from the 75% point to the 25% point (this is 150mm). A soakaway is basically a deep hole filled with rubble. If that isn't possible, you can discharge the rainwater into a sewer, although you will need to get permission from the water company first and they will charge you a yearly fee. Has anyone. Dig a series of parallel trenches every 3-6m across the garden, sloping towards the ditch or soakaway. They depend on soil with sufficient infiltration and absorptive capacity. Rebekah PooleOk well. If you are hoping to create a soakaway to alleviate waterlogging in a garden, you may well be disappointed by what follows. 49 50 3. It connects the existing drains giving a storage for the water coming off the fields before it goes in to the main drainage out the field. 1. Consequently,can you have a soakaway in clay soil?The excavation for the soakaway is usually done by mechanical diggers. fWhilst the base of a conventional soakaway will be in a suitable strata, loose Made Ground may be encountered close to the ground surface. It's best to think of water pouring into a soakaway rapidly then slowly draining away into the surrounding soil. then soil. Soakaway Size. 11 60 3. If there’s a lot of water and it doesn’t drain too quickly, then it should be bigger. The rate of this silting depends on several factor but principally the following. LeadFarmer said: Soakaways in clay soil just become ponds. This can cause wastewater to flood the surface of your property. Maintain healthy and level lawns. 8m deep. Digging a trench is one of the most effective ways to prevent waterlogging. You should place an impervious layer on top of the. Country. The volume of water being put into the soakaway: If a soakaway can't handle the water quickly enough then it will silt up at the bottom and eventually the sides will collapse. A cone of influence of 450 from the discharge points in a soakaway surrounded by soil with similar vertical and horizontal permeability can be used to provide an initial assessment of the zone of impact of a soakaway. ComponentsThis is useful if the soils are clayey and do not drain very well. DON'T install a soakaway in heavy clay soil, the water cannot drain through. In a clay soil it’s going to take a long time for any soakaway or finger drains to empty so you need to size them accordingly. Choose driveway surfaces that allow water to flow. The size of fly ash particles is commonly larger than the clay particles, thus the addition of fly ash changes the grain size distribution of the clay and reduces the liquid limit. However, the consolidation of the soils is time dependent, delaying construction projects making it a non-feasible alternative. However, if you are interested in trying to retain that water or have it distribute into the soil without muddying everything, you can create a soakaway pit to collect water. Step 3 – Prepare the base. Fill with decorative stones. We've rounded up the top driveway drainage solutions for you to recreate in your landscaping scheme. Step 4 – Hook up to the drainage system. Surface Water Drainage Options in Clay Soil Are soakaways suitable in clay soils? ©2023 by GeoSon. Vermiculite is good for root growth. This leads to aerobic digestion and effectively treats the effluent. The test procedure is outlined here. However, the consolidation of the soils is time dependent, delaying construction projects making it a non-feasible alternative. Can be used independently or as part of a larger system to collect and detain stormwater, allowing for groundwater recharge. Is there an alternative to a soakaway? 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. Start by digging a pit approximately 1. 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. Again though, not sure if these would likely just fill with water like a pond and leave puddles in the garden and how effect the water would feed into them. 0 m), and soakaway sediment were used for this study. The lowest average pH value is found in plant residues (pH ≈ 6. 25 inches per hour is needed to create an effective rain garden. Digging in a 1m3 soakaway using a soakaway crate near the centre back of the garden (at least 5m away from the house and 2. The pre-fabricated soakaway system offers an alternative to gravel when installing a French drain garden drainage system. dustmaker said: building regulations state that a new soak a way has to be at least 5. Free call for quote on. 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. Be sure the soil is a bit airy, too. The ideal garden drainage solution depends on. The crates feature voids, allowing large volumes of water sufficient surface area to seep back into the ground. In a word, peat is springy. Flo-Well® Accessories. Soil that consists of over 50 percent clay particles is referred to as “heavy clay. And it has cement powder. If it takes one to two hours for the. A Soakaway must be at least 5 metres from any habitable building, by local authority regulations. 23 4. Country. In clay soil, the effectiveness of a. If the water table is too high, then a soakaway simply won’t work there. you can go as close as is practical to the hedge. The second most important factor is the soil type - its condition and permeability - of where you would be installing the soakaway crates. Dig a series of parallel trenches across the garden every 3-6 meters, sloping toward the ditch or soakaway. 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. 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. Will a soakaway work in clay. While we recommend your groundworker conducts a soil percolation test and creates a set of calculations, there is an alternative method that will give you a rough idea of the soakaway size you’ll need: If your soil type is not too heavy/clay, you can assume that one crate (1000mm L x 500mm W x 400mm H) will be sufficient for ten sq. Sodicity degrades soil properties. Plastic septic systems are prone to buckling or caving in when put under this constant pressure. Plus, a cut pool noodle can help to improve drainage in hydroponic systems. )Jul 4, 2021. These fibers are an excellent material since they help orchids grow strong roots that can hold the plant together. e. This will allow rainwater to drain away. 2. Infiltration Test. 1. Rainwater soakaways are usually made from gravel or stone or even plastic soakaway crates. 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. DON'T install a soakaway within 5 meters of your home or a road, it must be installed over 5 meters away. Three types of samples viz. Step 5 – Cover the crates. How do you make a soakaway in clay soil here? It must extend below the clay and be at least 1. Manage the Moisture Using Berms. As an alternative to using gravel consider the prefabricated crates below. 3: Using Worms and Castings to Improve Clay Soil. Alternately, gardeners can build berms in the landscape to lift plants out of poor-draining clay. Stage 5 – Cover the crates. 4 Apr 2017. I've found that garden compost is best, but conditioners such as seaweed, farmyard manure, or bagged manure products like Scott's. If you have the space and some soil on the clay you could run an ACO channel anywhere out of the way. Country. Next, a long channel drain is placed in the trench. Consult your local planning department. Case History As part of a preliminary investigation for a barn redevelopment Geoinvestigate were asked to assess whether the site would be suitable for a SuDS. To work, it must extend below the clay and be at least 1. It doesn’t get compacted, which can suffocate new seedlings or cause root veggies to become stunted because they can’t push through dense clay soil types. Coffee husk ash (CHA) is a solid waste obtained by the processing of coffee beans on a farm or factory. 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. Because your soil is clay a traditional rubble filled hole will not be an adequate soakaway. If you have noticed that water tends to puddle on the ground rather than soak in, it is likely your soil is clay. Plastic chamber leach fields are great alternative septic systems for small lots and properties with high or variable groundwater tables. Underdrains can increase drainage over clay soils. Save time and money with the soakaway experts. Then mark and dig out the side trenches to connect to the main drain, forming a herringbone pattern. To work, it must extend below the clay and be at least 1. g. #10. moved the location of the discharge to more than 10 metres away from. It should be noted that soakaways rarely work on heavy clay soils. We've rounded up the top driveway drainage solutions for you to recreate in your landscaping scheme. Will Lime. Oliver W. Finding alternatives to natural resources is important for a sustainable future and is essential to infrastructure projects. 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. 2: Amend Your Clay Soil with Organic Matter. Installing a soakaway provides a means by which rainwater from a building can be collected and dispersed into the soil in a suitable location. When is a soakaway possible? A soakaway is possible when: The ground infiltration rate is greater than 1×10-6m/s. 28 Mar 2008. Well if you have a shallow clay cap on an otherwise free dining soil that might well work. 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. 5m away from the garden wall). How do I install a soakaway in my garden? Follow these 6 simple steps to install soakaway crates – both quickly and correctly: Step 1 – Create space. wcavanagh. I dug a channel out and have begun to dig a soakaway in the corner of the garden and am down about 1 metre so far, just gone past blue clay. 10 Jan 2017. February 2015. 2. 7 Sep 2013. Don't spill your soil. 1. The organic matter needs to be mixed into the top 6 to 12 inches of soil. 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. The fitter assured us that it was all done correctly and that it has been fitted into a soakaway. Usually we would recommend 10mm or 20mm pea shingle for this. Sodicity in soil is the presence of a high proportion of sodium ions relative to other cations. Safe-T-Sorb (STS) from Tractor Supply. A soakaway should be placed deep enough in the ground to reach well-draining soil. 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. #1. Chapter 3 1994 8. it may mean deeper than standard foundations particularly if you have clay soil. It's also soft rather than scratchy underfoot, unlike edible thyme varieties. Use a loose, organic-rich soil when building berms to enhance drainage. You may be able to discharge the water into a sewer if no other alternative exists and you have permission from the water company. In these circumstances a specialist software package is usually used, such as. septic tank soakaway in clay soilseptic tank and soakaway kit makes light work of clay soil. T. A rectangular grid allows alternative pathways. How do I install a soakaway in my garden? Follow these 6 simple steps to install soakaway crates – both quickly and correctly: Step 1 – Create space. The main aim of this study is to. Jan 20, 2015. Backfill the hole so the crates are secured. if your ground is relatively free draining then building control will insist upon a soakaway if practical. I use it as the inorganic component for most of my bonsai except really large ones. It allows water to filter through it, and literally soak into the ground ( away ). uk; Order In Next To Get It On Sep 14A soakaway works by encouraging rainwater to flow quickly through the soil into a hole or pit created. Tin Soldier; 13 Feb 2017;. 60 100 6. 4: Till in Amendments the Right Way. put soil, sand or similar material on the driveway that will block the surface and stop water soaking in. Vegetation – Dense vegetation on a rural surface can intercept and store a significant amount of rainfall, thereby reducing the catchment runoff. 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. Whereas if the soil is very sandy with a high infiltration rate, you can install a small soakaway. The way to determine the type of soil and how porous it would be is through a percolation test. soils with high clay content slow water infiltration and air penetration. As well as the back and side fill, a layer is also required on top of the soakaway crate, before the hole can be re-covered with soil and any other finishing. Fill the hole with water and come back and check it the next morning. K-Rod; 2 Sep 2013; In the Garden; Replies 2 Views 1K. * The soakaway fills up so isn't big enough. 35 80 4. To increase clay soil drainage, one must prevent compaction of the soil. 6 Porosity. ALL parts of the soakaway drainage field are required to be a minimum of: 10m from a watercourse or ditch. If the ground is unsuitable, like clay soils are, localised flooding can occur due to waterlogging. After (just recently) reading to manufactures instructions concerning the soakaway its states it need needs to be. A swale is like a ditch but it’s broad and shallow, and usually covered or lined with turfgrass or other vegetation. soakaway. What's more, pooling water beneath your deck can erode soil, harbor bacteria, and encourage insects such as mosquitoes. However, it’s a lot more subtle in terms of its appearance in the landscape. Open bag of clay and add water to surround clay and just cover top surface. Soakaway crates can be used to create a large storage volume or deep bore soakaways can be installed to. Log In. But must clay soils are quite deep. Prev 1. or soakage into the surrounding soil a series of factory-made plastic drop-in modular interlocking infiltration cell blocks wrapped in geotextile fabric. Clay soils typically do not drain very well and can in some cases be impermeable. You should receive some clips or ties with the crates. Start by digging the standard 1m x 1m x 1m trench, increasing the size if necessary,. septic tank soakaway clay soil - septic tank soakaway clay soilyour septic tank and soakaway in clay soil?Are you installaing. The diagram below is not to scale. approx 1800L per day like some technique to send the water into earth or is there. This can cause the soil to shrink, especially if it is predominantly clay, which has consequences for structures built on it. Follow these 6 simple steps to install soakaway crates – both quickly and correctly: Step 1 – Create space. This option is super popular for crafty hydroponic gardeners on a budget. connect condensate discharge pipe to the soil pipe or mains drainage. Paving reduces or stops rainfall getting into the ground. A soakaway is basically a deep hole filled with rubble. But of course it doesn’t have clay in it. Dig a series of parallel trenches every 3-6m across the garden, sloping towards the ditch or soakaway. This pit is then filled with coarse gravel, rubble or even plastic crates that allow the water to collect and filter through. Use a loose, organic-rich soil when building berms to enhance drainage. (The garden is about 3 foot higher than the extension's dampcourse) Its clear that any soakaway. it may mean deeper than standard foundations particularly if you have clay soil. This is useful where a soakaway pit or infiltration trench cannot be used because of impermeable soils (e. These are large plastic that helps to control the rate at which the water filters through the soakaway. 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. Top tips to reduce surface water flooding. In a clay soil it’s going to take a long time for any soakaway or finger drains to empty so you need to size them accordingly. So yes soakaways can work perfectly well in clay. They can’t tolerate competition very well. 8m deep A soakaway is basically a deep hole filled with rubble. Other than that it depends on how much water the soakaway will be processing and the perculation rate of the surrounding soil – i. Nature of the soil and its effect on the soakaway drainage field performance It is impossible to soak effluent away into a clay or clay-based soil in a normal soakaway drainage field. Soil Alternatives-Post them up. Allow winter frosts to work on clay and break it down. The permeability of the soil is akin to the size of outlet in the system I proposed above. Peat moss is a great first choice as an alternative to soil. 45 mm. Log In. 5m deep in a lower part of your garden and preferably at the bottom of a slope. Soil containing a high amount of clay is not a good choice for drainage and you may have to dig deeper to get past the clay layer. 24” diameter x 28. If using dried seaweed meal, apply 100–200 grams per square meter. Traditionally, a soakaway is just a large hole, lined with rubble. The soakaway should be encased by 100mm of free draining gravel on all sides. P = the maximum number of persons that the treatment system/tank is designed to serve. 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. W. In many cases, it will even work its way back to the surface over time, making your water-logging problems even worse. If your London property is built on heavy soil or clay-based soil, then a soakaway won’t be an effective choice. Author. Soakaway sediment was collected from an AIF, Nerima ward, Tokyo. This is drained to a soakaway or drainage field via the outlet pipe and the rest of the contents of the tanks stays put as ‘sludge’ until regular emptying, known as. #1. As an aid, mark a stick 300mm from one end, place in the hole and fill up to the mark. Cut pool noodles: A cut pool noodle can also be used as an alternative to hydroton. Or to dig deep holes and fill them with sand and bricks. How to Build a Soakaway in Clay Soil? A soakaway is basically a deep hole filled with rubble. If the soakaway has been constructed in non-permeable soils such as sandy clay, silt clay and clay then the effluent from the septic tank cannot filter away through the soakaway then flooding of the septic tank will occur causing it to overflow, causing a health hazard. The soakaway must be a minimum of; 5m away from your building 5m away from a road 2. 8m deep. In order to get a chamomile lawn established, you’ll need to remove the grass. This option is super popular for crafty hydroponic gardeners on a budget. It is lightweight and easy to work with, and it has a high water-holding capacity. Generally a soakaway built on non clay soil to take and disperse water from a gravel French drain system draining a 120 m2. 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. (2) If a subsurface treatment unit such as an absorption. The tank to soakaway outlet is generally 300-700mm below ground level, so we suggest carrying out the percolation test at this level in the subsoil. This is useful if the soils are clayey and do not drain very well. We sell our products through wholesale. Accessories include cover, additional panels, bottom, surface drain and filter fabric. Staffordshire. 5m away from the garden wall). Bore a hole 150mm in diameter with an auger, to a depth of one metre. While alternative drainage options exist, none are as efficient or cost-effective as a well-designed and. bennno. What is the best stone for a soakaway? 5 driveway drainage solutions for your front yard. Similarly some silts are also largely unsuitable, though this depends on the particle size. Soakaways are a drainage system for surface rainwater run-off. Gypsum is calcium sulphate and is touted as very beneficial for breaking up compact clay soils. roughly 2m x 1m, x 1. When building on a clay site a number of issues can increase costs. 98 90 5. The addition of organic matter is preferred to adding. Though any of the organic materials mentioned will help stop the clay binding and compacting which must help with drainage. When is a soakaway possible? A soakaway is possible when: The ground infiltration rate is greater than 1×10-6m/s. Water-loving plants like swamp milkweed ( Asclepias incarnata; pictured) or cardinal flower ( Lobelia cardinalis) both beautify and improve poorly draining areas. Area (A) = V X P X 0. Plant a variety of leafy vegetation to collect rainfall. filled the hole at 1820, and by 2217 it had possibly (possibly) moved 2cm, but I suspect. Ideally you prefer a soakaway rate of 1 x 10-5m/s in order to achieve the half emptying time1. Based on. you can go as close as is practical to the hedge. 5 metres is just from the building in any direction, it doestn have to be away from the sides. Garden walls, paths and houses may develop severe cracks; There are many additional benefits of not paving over front gardens or keeping the paving to a minimum:The soakaway should then be filled with 10mm limestone chippings; Soakaway Installation. I don't know what area you are in but a soakaway in the South East will cost nearer £350 + vat. As long as the. Perlite is an excellent amendment for clay soil when you want to increase the drainage and aeration of the soil. The ground it’s dug into should be lower than the building if. 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. orSee more of Soakaway Worms on Facebook. If you hit a layer of clay before reaching the required depth, simply make the soak away longer to make up for the lack of depth. The septic-tank youeffluent must be absorbed and. 1. Much reviled for some reason, but it worked for me. Digging in a french drain with perforated pipe along the side of the garden. (Using a tiller too often will actually impair soil drainage by breaking up soil aggregates. Other than that it depends on how much water the soakaway will be. Next OP Posts Only. Clay and clay-based soils have poor porosity: it is impossible to disperse the septic system effluent satisfactorily in such non-porous grounds. Best garden drainage systems in a nutshell. How deep should a soakaway be in clay soil? 1. New Channel - FREN. Steps: To build a basic stand-alone soakaway, dig a pit in your soft turf no less than 1m2 and 1. This is most common if the membrane is broken, the crates are the wrong size or capacity, or the pipes have. Underlying soils – This has a limited impact on man-made surfaces such as pavements, but has a very large effect on natural or agricultural surfaces. Location. The insides of the excavation can become smeared, particularly by mechanical diggers building a soakaway in clay soils. P = The maximum number of persons that the tank or plant is designed to serve. 2 metres from a boundary. Leach Field Design for Clay Soil. Soakaway: A soakaway is an underground structure designed to disperse water into the surrounding soil. The water the soakaway collects will drain into the soil below the layer of hard clay. The condensate pipe goes strait in to the ground right next to my. To work, it must extend below the. A soakaway may well be pointless in heavy clay and therefore your only other option would be to run the water off the surface and round a corner to a bed or lawn etc, depending on the surface area being drained this may not be suitable but for a small drive it would probably be ok. It is pointless sinking a soakaway in clay unless there is a more porous layer underneath. generally on a house extension, the gullies are joined by 110mm pipe below the ground and then 1 pipe goes to a soakaway. Be sure the soil is a bit airy, too. The location of the soakaway is determined based on soil conditions, distance from water sources, and the size of the property. Just squish it between your fingers. Step 2. Your soakaway should be at least one cubic metre, and be below the bottom of the feeder pipe. The least suitable soil types for a drainage field soakaway are: Clay soils (including soil with high clay content) Silty soils; If the percolation test results determine that the soil is in the "Goldilocks zone" of drainage - not to slow to drain discharge but not too quick to not treat it - the results will help with calculating the size of. Soakaways are viable for clay soils but normally need to be be another size up- (greater storage for later attenuation), for instance I know Aquacell quote numbers of. Furthermore, expanding clay soils with a COLE value greater than 0. To work, it must extend below the clay and be at least 1. You should place an impervious layer on top of the. This. #5. Topography, soil characteristics and composition of the effluent should be examined. 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. Common soil types are detailed in the table below. You should recieve some clips or ties with the crates. 8m deep. 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. The test procedure is outlined here. Determining the optimum size for a soakaway can be a complex iterative calculation including many factors such as location, soil types, size and shape, maintenance etc. A traditional soakaway will have a ratio at the higher end of scale where it drains a road or several houses. Essentially, the poorer the drainage, the bigger and deeper the hole needs to be. Septic tanks must always be subjected to a percolation test before they may be. 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. Turface. With nowhere for the water to go to it just fills up and sits there. Other clay soils will achieve a low infiltration rate which makes a rainwater. Set the plant on a third layer of gravel and turkey grit or sand. pour liquids such as oil on the surface. The Soak Pit which is also called the soakaway or soakage pit is a closed rectangular or. 20 for sewage treatment systems. Soakaway Pit Design. 2. ComponentsSimilarly,how do you make a soakaway in clay soil uk? A soakaway is basically a deep hole filled with rubble. 5m away from the house, and at 1 square cubic meter per 15 square meters of roof area the water falls from. started a discharge from a septic tank or small sewage treatment plant. Garden or driveway soakaways are usually much smaller than. This can sometimes be the case for soakaways installed in silty or clay soils. Maintaining the correct soil pH is highly important for crops. #1. 2m (4ft x 4ft x 4ft). Because your soil is clay a traditional rubble filled hole will not be an adequate soakaway. 3 Improve drainage in heavy soil. It will therefore flood due to the volume of water that the peaty soil holds. Is your septic tank and soakaway in clay soil? Are you installaing a septic tank and soakaway into clay soil? Would you like free help and advice about installing septic tanks and soakaways in clay soil? Then watch this video. 15 Sep 2021. Soil that is mixed with peat is much less dense. 24 30 1.