Floods and water management are the main reasons why SuDS (Sustainable Drainage Systems) are important in urban design and construction. To address these issues the UK’s BRE created a set of principles known as BRE 365.
This session looks at and tests soakaways which are a key component of surface water drainage systems. For engineers and developers to ensure long-lasting and efficient water management solutions BRE 365 testing is essential.
Always engage trusted professionals such as Ibex Consultants to ensure your testing procedures adhere to regulations!
BRE 365 Testing: What Is It?
One way to see if the ground is suitable for soakaway systems is to do BRE 365 testing. Soakaway drainage reduces the chance of flooding and surface water runoff by allowing rainwater to seep into the ground.
The test measures how fast the water seeps through the soil. When designing drainage systems for residential and commercial development this is crucial.
In what way do soakaways matter?
Reduce to minimum floods: Soakaways reduce the chance of flooding by allowing water to seep into the ground so reducing surface runoff. They are a key part of modern drainage systems.
Improve Water Quality: They remove impurities from precipitation before it gets to sources of groundwater.
Promote Sustainable Development: By mimicking natural hydrological processes Soakaways promote sustainable urban drainage.
The BRE 365 Testing Methodology
A multi stage process known as the BRE 365 test ensures accurate monitoring of soil infiltration rates. Here’s how:
Setting Up the Site and Property Selecting: Choose a soakaway location that takes in the whole property. The selected area must be free of obstructions such as tree roots and utility lines.
Excavation: Dig a test pit to a depth of one to two meters which is the estimated soakaway depth. The pit must be one square metre or larger.
Stabilisation: Make sure the pit sides are stable to prevent collapse during the test.
Testing
Filling the Pit: After pouring water to a certain depth (usually 300–600 mm) let the pit empty completely. This first filling has no measuring value as it saturates the soil.
Phase of measurement: After the hole has been filled again note how long it takes for the water level to fall by 75% of its initial height. Repeat this at least three times.
Calculate the Rate of Infiltration: Use the formula found in the BRE 365 guidelines. mm/hr is the standard unit.
Reporting and Data Analysis
Examine the Information: Examine the results to see if the soil is suitable for a soakaway. A higher rate of infiltration means a better fit for soakaway installation.
Report: Compile the information into a full report including the location, test results and drainage system design.
Factors Affecting Infiltration Rates
Type of Soil
Sandy Soils: Sandy soils have high infiltration rates due to their larger pore diameters which allow faster water flow. Clayey soils have smaller pore spaces and expand when wet which restricts water flow. Their infiltration rates are low.
Loamy Soils: These soils are suitable for drainage applications as they have moderate infiltration rates.
Compacted soil: These soils has less pore space and infiltration. Make sure the test area reflects the natural composition of the soil.
Initial Moisture Levels for Moisture Content: The moisture content of the soil before testing may affect the results. Standardising the first saturation phase is a good idea to provide consistent measurement conditions.
Flora and Organic materials
Root Systems: By allowing water to seep through the soil plant roots can strengthen the soil structure and increase infiltration rates. Organic Matter: Enhances the porosity and structure of the soil allowing better infiltration.
Building Soakaways according to BRE 365 guidelines
To control surface water a soakaway can be designed using the determined infiltration rate. The following are key to soakaway design:
Finding the Size of the Soakaway Capacity: The infiltration rate can be used to determine the soakaway size. This means how much to store and how fast the soil can absorb water. Provide extra capacity for extreme weather or unexpected rises in surface water runoff. This is known as buffer capacity.
Location and Fashion: Make sure the soakaway is a safe distance from buildings and other structures to prevent water ingress and structural damage.
Design of Landscapes
Construction Supplies: When designing a soakaway that fits the landscape consider both use and aesthetics.
Use gravel to provide room for water to move and store and geotextile membranes to prevent soil from getting blocked. Perforated pipes are recommended to improve water penetration and diffusion in the soakaway.
Regulation and the Environment
Building codes: Check the soakaway construction and design comply with local building codes and environmental standards.
Approvals for planning: Make sure you have all the necessary permits from the local authority before you start construction.
Effects on the Natural World
Protection of Groundwater: Take precautions to prevent pollution and consider the impact on groundwater.
Conclusion
When designing and implementing sustainable drainage systems, BRE 365 testing is essential. It helps architects and developers to design efficient soakaway systems that reduce flood hazards and advance environmental sustainability by giving precise data on soil penetration rates. Although there are obstacles, following best practices and taking site-specific factors into account can result in drainage solutions that are both successful and compliant with regulations while safeguarding natural resources.
Even in this day and age, when urbanisation and climate change present formidable obstacles to water management, BRE 365 testing is still a vital instrument for achieving resilient infrastructure and sustainable development. Stakeholders have the ability to create safer and more sustainable communities for future generations by comprehending and putting the testing method’s guiding principles into practice.
