SuDS: Retrofit roundtable

susdrain has championed sustainable drainage systems (SuDS) for over ten years.

We know that using SuDS to manage surface water delivers multiple benefits to places, people, wildlife and the environment. SuDS should be included in all new development to: (amongst other things) help manage surface water runoff for reduced flooding, improve receiving water quality, improve biodiversity, provide amenity and aesthetic value, conserve water resources and help adapt to climate change.

To maximise the benefits SuDS provide, they should also manage surface water in the existing built environment. Retrofitting SuDS to existing infrastructure requires a different approach to planning SuDS right from the start, although SuDS principles remain applicable. Retrofit can be large-scale for a whole area or more opportunistic, perhaps installing smaller scale (often replicable) SuDS when other work is being done.

There are many things to consider in a retrofit project such as buried utilities, traffic management, pedestrian use of the site and ease of maintenance – involving a variety of players, not all of whom will be familiar with the use of SuDS.

SuDS retrofits are a cost-realistic means of climate change adaptation for surface water drainage in established urban areas. They are also a cost-effective means of addressing combined sewer overflows – a major issue for water companies. It is important that they are urgently progressed.

A national retrofit surface water management strategy will enable optimal solutions that take account of new development and create capacity for new foul flows into existing combined systems. This strategy should align with adoption of new SuDS through enactment of Schedule 3.

Short presentations set the scene for discussion on what should be included in a national strategy for retrofitting surface water management.

Our experts discussed the challenges and opportunities for retrofit SuDS based on audience questions. Key outcomes from the discussion will feed into a proposition for a national strategy.