In the past, detailed drainage strategies have been required for major developments (10 properties or more), however we are now seeing Local Planning Authorities (LPAs) request a more detailed design utilising the features of a SuDS report on smaller developments.
While the exact methods may vary among LPAs, a standard drainage plan made by drainage design consultants typically outlines the following:
- The site’s attributes, including its slope profile, soil geology, and existing flood risk.
- Calculated rates of surface water runoff, such as a soakaway calculation, and the corresponding storage capacity requirements.
- The designated discharge points for the runoff. (Infiltration/Watercourse/Public Network)
- The proposed sustainable drainage system (SuDS) components.
- Strategies for the management and maintenance of the drainage system.
- Overland exceedance maps to ensure consideration has been taken from excess runoff both on and off site.
What to Expect
In a drainage strategy, you can expect:
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- Calculations proving the proposed site does not flood in a 1in100 year storm even plus 40% for Climate change for residential or 20% for commercial developments. It should be noted that climate change percentages can vary with LPA.
- Proposed drainage layout (plan/drawings) confirming pipe and manhole sizes, gradients and locations.
- Typical construction details including SuDS features
- Drainage statement to support all proposals with consideration of SuDS in accordance with the SuDS hierarchy.
- Maintenance strategy for all elements including SuDS features.
The above may vary slightly depending on the LPA.
Selecting the Suitable Drainage Strategy Design for the Location
A crucial initial phase for achieving the correct design is to grasp the ground’s drainage conditions and assess the site’s suitability for infiltration. Onn Point offers an overview of the site’s appropriateness for various Sustainable Drainage Systems (SuDS) alternatives, including services like percolation tests, BRE365 soakaway testing, and more. If you would like to discuss your project, please feel free to contact us.
What a drainage strategy is
Introduction:
Drainage design plays a crucial role in the success and sustainability of civil engineering projects. From managing stormwater runoff to maintaining the integrity of infrastructure, a well-planned drainage strategy crafted by drainage design consultants is essential. In this article, we will delve into the concept of drainage strategy, its importance, and how it contributes to sustainable urban drainage. As a leading civil engineering design consultancy in the UK, we aim to provide you with valuable insights into this critical aspect of infrastructure development.
What is a Drainage Strategy?
A drainage strategy is a comprehensive plan that outlines the approach to managing water and controlling its flow within a specific area. It encompasses various techniques, methodologies, and considerations related to the design, implementation, and maintenance of drainage systems. A well-developed strategy ensures effective water management, reducing the risk of flooding, preventing damage to infrastructure, and preserving the natural environment.
The Significance of Drainage Design:
Proper drainage design – especially for highway design is essential to maintain the integrity and longevity of structures. A well-designed drainage system efficiently collects and redirects excess water, preventing erosion, structural damage, and soil instability. Moreover, it helps protect buildings, roads, and other infrastructure from water-related issues such as dampness, seepage, and corrosion. A robust drainage strategy is particularly vital in urban areas where increased impermeable surfaces can amplify stormwater runoff.
Sustainable Urban Drainage and its Role:
Sustainable urban drainage, often referred to as SuDS, is an integral part of modern drainage strategies. SuDS aims to mimic natural water management processes by incorporating features that promote infiltration, storage, and treatment of stormwater at its source. This approach minimises the burden on traditional drainage systems, reduces the risk of flooding, and helps enhance the overall sustainability of urban areas.
Key Components of a Drainage Strategy:
1. Site Analysis: A thorough assessment of the project site, known as a SuDS report, is crucial to identify existing drainage patterns, natural watercourses, and potential issues related to soil composition or topography. 2. Design Considerations: Drainage design must consider factors such as anticipated rainfall, land use, infrastructure requirements, and environmental regulations. Sustainable techniques, including permeable paving, green roofs, and rainwater harvesting, should be incorporated where feasible. 3. Runoff Management: The strategy should outline how stormwater runoff will be managed. This may involve the use of retention ponds, infiltration basins, swales, or underground storage systems to control and redirect water. 4. Maintenance Plan: Regular maintenance is essential to ensure the longevity and functionality of drainage systems. The strategy should include a plan for inspection, cleaning, and repairs to prevent blockages and maintain optimal performance.
Conclusion:
A well-developed drainage strategy is a cornerstone of successful civil engineering projects. By incorporating sustainable urban drainage principles, it is possible to mitigate the adverse impacts of excess water while promoting environmentally friendly practices. As a reputable civil engineering design consultancy in the UK, we prioritise the implementation of effective drainage strategies to ensure the resilience, safety, and longevity of infrastructure. Contact us today to learn more about the expertise of our drainage design specialist team and how we can assist you in developing sustainable solutions for your projects.
If a drainage condition has already been attached to your permission, what to do when you receive planning conditions covers what happens next.