It is encouraged to explore all opportunities for using SuDS features on a site to ensure it is much more environmentally friendly and provide visual appeal, biodiversity and pollution treatment benefits.

It is also usually a requirement of the local development plan and the lead local flood authority to incorporate as many SuDS into a development as possible, especially ‘green’ SuDS features such as ponds, swales and bioretention systems.

The suitability of a SuDS feature for a development depends on a number of factors. These  include the constraints of the site and how each SuDS feature provides drainage.

Any particular site can be tailored to include a combination of SuDS features, but these would be dictated by the constraints of the site.

To find out which SuDS features can be included, these questions are among those that should be asked:

• Is the site greenfield or brownfield? Greenfield sites usually have higher attenuation requirements but brownfield sites may have less space SuDS such as ponds or swales.
• What are the existing ground conditions? This indicates whether infiltration is feasible on the site and if SuDS such as pervious pavements and soakaways can be used.
• What is the proximity of the SuDS to buildings and sewers? The SuDS must be sufficiently distanced from these to avoid structurally compromising foundations or pipes.
• What spaces are available for vegetation and landscaping? This would permit the inclusion of the ‘green’ forms of SuDS such as rain gardens, tree pits and swales.
• What is the intended use of the site? If the site is industrial, this may need a proprietary treatment system such as an oil separator to treat pollution in surface water. Likewise, a residential site may offer more ‘green’ SuDS opportunities compared to a commercial site.
• What surface water flow rate leaving the site is permitted? The local requirements for greenfield and brownfield sites will vary for the discharge of surface water.
• How do the levels vary across the site? Many of the SuDS features require a fairly level platform and the SuDS should be positioned to provide positive drainage of the site.

The engineers here at Link have extensive experience in the applying SuDS features to drainage strategies are continually up to date with the latest SuDS best practice and guidance.