How to Make a Drainage Soak Pit - Auckland Drainlayers

When it comes to managing water drainage on your property, creating a drainage soak pit can be a practical solution. This underground structure allows excess water to slowly percolate into the ground, preventing it from pooling or causing damage.

But how exactly do you construct one? In this discussion, we will guide you through the step-by-step process of making a drainage soak pit, from selecting the ideal location to testing its effectiveness.

By the end, you will have a comprehensive understanding of this method, empowering you to effectively address your water drainage concerns.

So, let's dive into the intriguing world of drainage soak pits and uncover the secrets to their successful creation.

Gather Necessary Materials and Tools

To begin the installation of a drainage soak pit, gather the essential materials and tools required for the project. These include geotextile fabric, coarse gravel, perforated pipe, construction blocks, a crowbar, square mouth shovel, digging spade, cement mixture, a large sheet of metal or plywood, EcoGrid Graf Soakaway 300 Litre crate, landscaping fabric, and materials for connecting trenches.

Geotextile fabric is a crucial component of a drainage soak pit as it helps in filtering out debris and preventing clogging of the soak pit. There are different types of geotextile fabric available, such as woven and non-woven. Woven geotextile fabric is durable and provides good filtration, while non-woven fabric is more commonly used for erosion control. It is important to choose the right type of geotextile fabric based on your specific project requirements.

Regular maintenance is vital to ensure the proper functioning of the drainage soak pit. This includes periodic inspection of the geotextile fabric for any signs of damage or clogging, cleaning out accumulated sediment and debris, and checking the perforated pipe for any blockages. Neglecting regular maintenance can lead to reduced drainage efficiency and potential damage to the soak pit system.

Choose the Location for Your Drainage Soak Pit

When selecting the location for your drainage soak pit, it is important to consider factors such as the absence of low, wet spots, limited foot traffic, available space, soil type, and proper water drainage. Finding the ideal location for a drainage soak pit is crucial to its effectiveness and longevity. Here are some factors to consider when choosing a soak pit location:

Factors to Consider	Description
Absence of low, wet spots	Choose an area that is elevated and not prone to flooding or water accumulation. This will prevent the pit from becoming waterlogged and ineffective.
Limited foot traffic	Select a location away from areas with high foot traffic, such as walkways or driveways. This will prevent damage to the soak pit and ensure its longevity.
Available space	Consider the amount of space available for the soak pit. The size of the pit will depend on the amount of water it needs to drain, so ensure that the chosen location can accommodate the required size.
Soil type	The type of soil in the chosen location will affect the drainage capacity of the soak pit. Sandy or loamy soil is ideal as it allows for better water percolation compared to clay soil.

Dig a Hole for the Soak Pit

Begin by excavating a 1-meter cube-shaped hole in the ground for the soak pit. The excavation techniques used during this process are crucial to ensure the proper functioning of the drainage system. When digging the hole, it is important to consider the soil composition of the area. Different soil types have varying drainage capabilities, so understanding the composition will help determine the size and depth of the pit.

To begin the excavation, use appropriate tools such as shovels, spades, or excavators depending on the scale of the project. Carefully remove the soil, ensuring the walls of the hole are straight and vertical. This will prevent any collapse or instability during the construction process.

While digging, it's essential to analyse the soil composition. Sandy soils have better drainage properties, while clayey soils tend to retain water. If the soil is predominantly clayey, it may require additional measures to enhance drainage, such as adding coarse sand or gravel to the soak pit.

The size of the hole should be adjusted based on the available space and the soil type. It is crucial to ensure that the walls of the pit are covered to prevent dirt from filling inward, as this can obstruct the drainage process.

Install a Perforated Drainage Pipe

When installing a perforated drainage pipe in a drainage soak pit, there are several important points to consider. Firstly, the installation process must be followed correctly to ensure proper functioning of the drain. Secondly, it is crucial to choose the right type of pipe that is suitable for the specific application. Lastly, ensuring proper drainage is essential to prevent water buildup and potential damage to the soak pit.

Before beginning the installation, it is important to gather all the necessary materials and tools. These may include a perforated drainage pipe, gravel, geotextile fabric, a trenching shovel, a pipe cutter, and a tape measure.

Start by determining the location and size of the soak pit. Dig a trench that is at least 1 meter deep and wide enough to accommodate the perforated drainage pipe. Ensure that the trench has a slight slope to allow for proper water drainage.

Next, line the bottom of the trench with a layer of gravel. This will help to promote water flow and prevent clogging of the drainage pipe. Place the perforated drainage pipe on top of the gravel, ensuring that the holes are facing downwards.

Cover the drainage pipe with another layer of gravel, ensuring that it is evenly distributed. This will help to prevent the pipe from becoming exposed or damaged.

Once the pipe is covered with gravel, wrap it with geotextile fabric. This will help to filter out any sediment or debris that may enter the pipe, ensuring its proper functioning.

Finally, backfill the trench with soil, ensuring that it is compacted properly. This will help to provide stability to the soak pit and prevent any potential damage.

It is important to regularly inspect the drainage pipe and soak pit to ensure that it is functioning properly. If any issues are identified, it is important to address them immediately to prevent any potential damage or water buildup.

Pipe Installation Process

To properly install a perforated drainage pipe for the soak pit, it is crucial to select a suitable location that aligns with the overall drainage system and intended function. Once the location is determined, the pipe installation process can begin.

Excavate a trench, ensuring it slopes at a 6 mm for every 3 meters in length to facilitate proper water drainage towards the soak pit.

Lay the perforated drainage pipe in the trench, making sure to place it with the perforated side facing downward to allow water to enter.

Backfill the trench with sand or gravel to secure the pipe and ensure proper drainage towards the soak pit.

Finally, complete the installation by covering the soak pit with rocks, a metal sheet, or plywood, and ensure that the top is protected and secure.

Proper pipe maintenance and troubleshooting common issues will help ensure the effective functioning of the drainage system.

Choosing the Right Pipe

Selecting a perforated drainage pipe suitable for the installation of a soak pit requires careful consideration of material durability and corrosion resistance.

The chosen pipe should be made of a material that can withstand the harsh conditions of the surrounding soil and water. Common options include PVC, HDPE, and corrugated metal pipes.

PVC pipes are lightweight, easy to install, and resistant to corrosion, making them a popular choice for soak pits.

HDPE pipes offer excellent strength and durability, making them suitable for heavy-duty applications.

Corrugated metal pipes are known for their high resistance to corrosion and can be a good choice for long-term use.

Regardless of the material, regular maintenance is crucial to ensure the longevity and effectiveness of the drainage pipe. Regular inspections and cleaning will help prevent blockages and ensure efficient water drainage.

Ensuring Proper Drainage

One essential aspect in ensuring proper drainage for a Soak Pit installation is the careful installation of a perforated drainage pipe at its centre. This pipe allows water to flow freely, preventing flooding and protecting foundations from water damage.

To ensure effective drainage, it is important to choose the right materials and follow proper maintenance tips.

Here are some key points to consider:

Choose a perforated drainage pipe that is durable and resistant to blocking.
Line the soak pit with geotextile fabric to prevent soil erosion and filter out sediment.
Surround the perforated pipe with a layer of gravel to facilitate water percolation.

To maintain the functionality of the drainage pipe, regular inspection is necessary. Check for any signs of blocking or sediment buildup, and make necessary repairs promptly.

Surround the Pipe With Coarse Gravel

When it comes to surrounding the perforated pipe with coarse gravel, there are two key points to consider: pipe placement and gravel layering.

Proper pipe placement ensures that the pipe is positioned in a way that allows for efficient water drainage.

In terms of gravel layering, it is important to evenly distribute the coarse gravel around the pipe to create a supportive and well-draining layer.

Pipe Placement

To ensure optimal drainage, it is essential to surround the perforated pipe with a layer of coarse gravel. This step is crucial for maintaining the functionality and longevity of the drainage system.

Here are some key points to consider when placing the pipe:

Choose the appropriate pipe size: Depending on the amount of water expected to be drained, select a pipe size that can handle the anticipated volume. This will help prevent overflow and potential damage to the system.
Properly position the pipe: Place the perforated pipe at the lowest point of the soak pit to ensure that water flows towards it. This will maximize its effectiveness in draining excess water.
Cover the pipe with coarse gravel: Completely surround the pipe with a layer of coarse gravel. This will serve as a filter, preventing fine soil particles from entering and clogging the pipe.

Gravel Layering

The proper placement of coarse gravel around the perforated pipe is vital for ensuring efficient water infiltration and preventing clogging in the drainage system.

The size of the gravel used is an important factor to consider. It is recommended to use gravel with a diameter of 10 to 20 millimeters, as this size allows for good water flow while still preventing the entry of soil particles into the pipe.

Additionally, alternative materials such as crushed stone or crushed rock can be used as substitutes for gravel, as long as they provide the necessary permeability and stability.

The layer of coarse gravel should be evenly distributed around the pipe to promote efficient drainage. This layer not only facilitates water infiltration but also provides support for the perforated pipe, helping to maintain the integrity of the soak pit structure.

Cover the Gravel With a Layer of Geotextile Fabric

In order to ensure proper drainage and prevent clogging, it is essential to cover the layer of gravel with a geotextile fabric in a drainage soak pit. The geotextile fabric provides several benefits and plays a crucial role in maintaining the functionality of the soak pit system.

Geotextile fabric benefits:

Acts as a barrier: The fabric acts as a barrier, preventing soil and debris from entering the gravel layer. This helps to maintain the integrity of the soak pit system by preventing clogging and ensuring efficient water percolation.
Filters and separates fine particles: The geotextile fabric aids in filtering and separating fine particles from the water. This promotes better drainage and prevents the gravel layer from getting clogged over time.
Prevents soil infiltration: By securely covering the gravel layer, the geotextile fabric prevents soil infiltration into the soak pit. This is important as soil infiltration can reduce the capacity of the pit and hinder its effectiveness in draining water.

Backfill the Hole With Soil

After ensuring proper drainage and preventing clogging by covering the gravel with geotextile fabric, the next step is to backfill the hole with soil to create a stable base for the soak pit. Backfilling with soil is crucial as it helps to cover the rocks and provide a solid foundation for the soak pit. The type of soil used for backfilling should be a mixture of topsoil and subsoil to ensure proper drainage.

To ensure stability and prevent shifting or settling of the soak pit, the backfilled soil needs to be packed firmly around the rocks. This can be achieved by compacting the soil in layers, making sure to eliminate air pockets. Soil compaction is essential as it increases the density of the soil, making it less prone to erosion and providing a sturdy base for the soak pit.

In addition to soil compaction, backfilling with soil also helps in preventing soil erosion. By filling the hole with soil, it creates a barrier that holds the surrounding soil in place, preventing it from being washed away by water or other external factors.

When backfilling, it is important to slightly raise the top layer of soil above the surrounding ground level. This allows for settling over time, ensuring that the soak pit remains level and functional.

Test the Soak Pit for Proper Drainage

To assess the effectiveness of the soak pit's drainage, it is necessary to fill the pit with water and observe the rate at which it percolates into the ground. This step is crucial to ensure that the soak pit functions properly and efficiently.

Here are some testing methods and troubleshooting tips to consider:

Monitor and record the time it takes for the water level to drop in the pit. This will give you an indication of how quickly the water is draining. Ideally, the water should percolate into the ground within a reasonable time frame.
Ensure that the water percolates effectively and does not accumulate on the surface. If you notice any pooling or slow drainage, it may indicate a problem with the soak pit's design or location. Adjustments may be necessary to improve the drainage.
Verify that the soak pit can handle the expected volume of water and drains it within a reasonable time frame. If the soak pit is unable to handle the anticipated water flow, it may need to be resized or additional pits may need to be constructed.

Frequently Asked Questions

How Is Soak Pit Constructed?

Soak pit design involves conducting a percolation test to determine the ground's soakage rate and drilling a test hole for the expected depth. Maintenance includes lining the pit with geotextile fabric, using coarse gravel and a perforated pipe, and covering it appropriately.

What Are the Requirements for a Soak Pit Nz?

What Are the Requirements for a Soak Pit NZ?

The requirements for a soak pit in New Zealand include conducting soil testing to determine the soakage rate of the natural ground and obtaining building consent approval. Proper installation of the soak pit is essential for effective drainage.

What Materials Are Needed for Soak Pit Filling?

To fill a soak pit, the required materials typically include gravel, crushed stone, and perforated pipes. The cost estimation for soak pit filling depends on the size of the pit and the quantity of materials needed.

What Is the Best Material for a Soakaway?

The best material for a soakaway is the EcoGrid Graf Soakaway 300 Litre crate with membrane. It is essential for soakaway construction and maintenance as it provides efficient water drainage and prevents soil erosion. This material is widely used in New Zealand and is available at a cost of NZD 200.

Conclusion

In conclusion, creating a drainage soak pit involves:

Digging a hole
Installing a perforated drainage pipe surrounded by coarse gravel
Covering the gravel with geotextile fabric
Backfilling the hole with soil

This method helps to:

Effectively manage excess water
Prevent soil erosion

By following these steps, you can create a functional and efficient drainage solution for your property.