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.
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...
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.
(Sustainable Drainage Systems)
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.
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.
can replace car parks and paths with materials that don’t shed water, such as:
- 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.
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.
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.
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.
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.
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: