You Can Slow The Flow: Public Spaces

Reduce flooding using our common ground

Due to human development, replacing plants and soils with hard surfaces such as roofs, roads, patios and car parking, rainfall runs off much more quickly, causing surface water and combined sewer flooding, and higher river levels.

How public spaces contribute to flooding through run-off

Using SuDS to Slow The Flow in our urban areas, as well as upstream, we can mimic natural water management. Many small changes can have a big combined effect on reducing flood water quantity and quality.

SuDS also have multiple Green Infrastructure benefits for health, economy, recreation, wellbeing, biodiversity, air quality, etc…

You Can Slow The Flow : Public Spaces - SuDS

When can we Slow The Flow?

We hope you are able to be proactive and start right away!

However, you may not have resources to do anything right now. If so, next time you repair or refurbish property, please consider SuDS.

Smaller Spaces

Take a look at our ‘At Home’ information as well, for ideas that might be applicable to businesses with smaller-scale spaces

SuDS Elements

(Sustainable Drainage Systems)

Rain Gardens

are planting areas that are deliberately located where they collect run-off and store it temporarily – they become boggy in downpours. As they are dry most of the time, many everyday plants can cope with the conditions. A layer of gravel below the topsoil helps increase storage capacity.

Urban Square Rain Garden Leeds
Roadside verge Rain Gardens, Scunthorpe

Rain gardens can collect run-off from paved areas, or take water from the roof via diverted drainpipes. So long as there is a plan for any overflow, they can be built over existing surfaces. Excess water can continue into the existing system, as before.

Retrofit rain garden in roadside verge

Permeable Surfaces

can replace car parks and paths with materials that don’t shed water, such as:

  • gravel
  • reinforced grass
  • porous surfaces
  • permeable paving
  • slabs/setts on gravel and without mortar

If constructed correctly, extra water can be stored underneath, using a layer of stone, or in special crates, whilst allowing the surface to continue to be used.

Gravel car park and swale
SlowTheFlowPublic-Upton Permeable Paving
Permeable gravel parking


can just be a dip in a lawn, or can be planted with meadow seed and plug plants, to provide a biodiversity corner that needs mowing less often.

Swale Floriade
Swale Olympic Park

Swales are usually dry most of the time, but can be designed to hold water for amenity. They can direct water to a pond, or just allow it to soak away.

Green Roofs

and blue roofs (without vegetation) can be put on all flat/gently sloping roofs, from large public buildings to bicycle shelters. Professional advice should be sought, to ensure loading and waterproofing are appropriately handled.

Bus stop with green roof, Manchester
Green Roof Brighouse

Sedum roofs and blue roofs can be lighter than biodiverse planting schemes, which need deeper soil. All can be designed to need very little maintenance.


have multiple benefits for biodiversity, air quality, aesthetics, health and wellbeing.

They also improve the rate at which water infiltrates the soil, and reduce erosion (preventing sediment from blocking water courses). Tree pits in paving can be designed to store and slowly release water.

Tree Pit Bridlington
Tree and planting in rain garden

Detention Basins

are shallow, planted areas, that are usually dry, but collect heavy rain.

They can be any scale, and can either allow the filtered water to infiltrate the ground, or send water slowly to the traditional drainage system via an outfall.

Detantion Basin Hull
Detantion Basin Sheffield
Detantion Basin Hull

Larger Projects

Interventions for larger premises or plots are more likely to need professional advice – particularly if you intend to:

  • increase the volume at any outfall point
  • work very close to a permanent river or stream (within about 10m)
  • make changes to a listed building or in a conservation area
  • create a green roof
  • re-use grey water in buildings
  • create reed beds to treat waste water
  • do anything that could affect neighbours

NB. Remember we have a varied geology, i.e. water runs through sand, but if you are working with clay, it may puddle rather than soak in.

 Download the printable 2-page PDF below:

The You Can Slow The Flow resource was 2017 winner of ‘Best Project’ at the Sustainable Water Industry Group Awards. These pages have been kindly sponsored by our friends in the Calderdale Flood Partnership, through the SOURCE partnership, and created by 2B Landscape Consultancy Ltd.