© Richard Sutcliffe (Licensed under CC BY 2.0). Kindly recommended by UKCEH.
Synonyms: SuDs, blue roofs, rainwater harvesting systems, modified tree pits
Elements designed to manage surface water to aid in reducing flooding and increasing water quality. SuDS provide an alternative or addition to conventional drainage systems that rely on pipes and the rapid conveyance of rainwater to drains and watercourses
SuDS originates from the Low Impact Development approach, which began in the United States in the 1990s. In the UK, with increasing interest in these practices, CIRIA published its first SuDS Manual in 2007. The Flood and Water Management Act 2010 (as amended) uses the term sustainable drainage and the National Planning Policy Framework (NPPF) has a policy that major developments should incorporate sustainable drainage systems unless there is clear evidence that this would be inappropriate. SuDs should ensure the storage of water in soils that can continue to support vegetation during drought, and which can provide evaporative cooling during heatwaves. (Source: Natural England)
The SuDS philosophy (as set out in CIRIA’s SuDS Manual 2015) is to consider the quantity of water, the quality of water, and improvements to amenity and biodiversity. The SuDS approach promotes a management train (or treatment train) for surface water. This involves a succession of features and connections (conveyances), taking surface water from source control features (e.g., green roofs, rainwater harvesting tanks and permeable paving) to site control features (e.g., rain gardens or small ponds) to regional control features (e.g., large ponds, wetlands, or detention basins), before sending water to watercourses. The building blocks of green infrastructure, described in the paragraphs that follow, include source control features, which should all individually be designed for amenity and biodiversity as well as their capacity to handle water. Source control features should be prioritised over site or regional controls to maximise overall effectiveness and minimise land take. The enhancement of biodiversity should be considered in all projects. (Source: Natural England)
Assessment Questions:
- Does the site include features for surface water management?
- Is the system effectively managing rainwater and surface runoff, controlling water flow, and reducing flooding?
- Does the system have mechanisms for improving water quality through processes like filtration, sedimentation, or biological treatment?
If YES, then it is likely “Urban - Sustainable drainage system”
How to Create / Enhance to a "Good" condition
Please refer to the National Standards for sustainable drainage systems and the National Planning Policy Framework
How to get a "moderate" rating
In a management plan aiming to achieve a ‘moderate’ condition, the plan will show:
There will be a range of different plant species that flower at different times of the year, providing nectar sources for a range of insects and other invertebrates.
So far as initially possible, the plant species will be composed of mostly native species. Any non-native plant species will be not harmful to wildlife and exclude invasive non-native species (INNS).
Source: Natural England
How to get a "good" rating
In addition to the characteristics for moderate condition, to get a ‘good’ condition the plan will include these features:
There shall be a variety of plants and habitat components to give structure to the bioswale or SuDs habitat and to ensure that no single habitat component or vegetation type covers more than 80% of the habitat area.
As soon as possible, steps will be taken to ensure that the site is composed of 100% native species that are suitable for wetland environments, including the structural vegetation types, or native species characteristic of pond edges.
Source: Natural England
Useful Resources
Guide 1 - SuDS Manual
Please note that this is a simple guide to help identify the habitat. For a definitive description, please refer to UKHab documentation. Joe's Blooms takes no responsibility for the content of external links.