You Can Slow The Flow

Everybody living or working in the Calder Valley can make small changes to slow the flow of stormwater.

Many small interventions, to slow run-off, could result in a significant amount of water being temporarily stored during storm events in our urban areas.

This will help to reduce peak flows (see the detailed Storm Hydrograph) which, together with catchment management and traditional flood defences, would contribute to reducing the scale and damaging effects of flood events.

SuDS NFM principles Section Diagram

Principles of SuDS

Sustainable Drainage Systems (SuDS) mimic the natural cycle of water management, by retaining water where it lands (instead of shedding it quickly to drains and watercourses, which can lead to floods).

SuDS reduce rainwater runoff from a given site, filter it to improve water quality, and slow its journey downstream.

Sustainable drainage allows us to Slow The Flow in Calderdale’s urban environment. This complements rural Natural Flood Management (NFM) measures. SuDS and NFM are in fact describing the same thing, but SuDS is more often the term associated with the urban environment.

We can also consider altering our behaviour during flood events to discharge less water into drains (much as we might behave to conserve water during drought).

Roadside verge transformed into a Rain Garden

Why?

During and after the devastating Boxing Day Flood 2015, thousands of us gave our time and money to help friends, family and neighbours recover.

If we all work together to take action and invest in our own properties (whether they flood or not) we can help reduce the threat of similar levels of flooding in the future, and the need to help clean up on such a large scale.

If every person in Calderdale (200,000 approx) stored an average of 0.1m³ (about a half-full bathtub) of water in a flood event, we could store around 20,000m³ (about 5 m³ for every property that flooded on Boxing Day 2015).

This could make a real difference, especially to water quality in areas which suffer from sewer flooding.

Rain Garden in a small space

Retrofitting urban SuDS is also a chance to contribute to local Green Infrastructure, improving:

  • wildlife value
  • air quality
  • the appearance of your property.

What?

Urban SuDS might include:
Download 'You Can Slow The Flow: General Principles' PDF (0.75MB)

Be a water hoarder

Green Roofs on domestic sheds, North Cave

Help to prevent combined sewer overflows by altering your actions during flood events to discharge less water into drains (as you might in drought – e.g. shower rather than bath, wait to use the washing machine…)

Yorkshire Water provide tips and free water saving packs.

Quick Wins

Sign up to receive Environment Agency Flood Warnings (even if you’re not in a flood zone)

Make water butts into ‘mini leaky dams’ in winter! Leave the tap open slightly before a storm so they can drain down, then act as mini dams, slowing the rainwater from your roof.

Roadside verge Rain Gardens, Scunthorpe

Where? Everywhere!

Locations such as:
  • Back Gardens
  • Front Drives
  • Sheds
  • Bin stores
  • Roadside verges
  • Public spaces
  • Central reservations
  • School grounds
  • Car parks
Permeable path and bin store green roof at RHS Hampton Court Show ‘Greening Grey Britain’ Demonstration garden
Swale at the Olympic Park: fills up only in heavy rainfall

How?

General Principles

Visit the page or download our printable 2-page PDF to get started

Download 'You Can Slow The Flow: General Principles' PDF
Hints, tips and links to SuDS information that are useful to everybody

 More?

Visit our ‘SuDS Links‘ page for further information. Watch the videos of our public meeting on this topic:
Chris Griffiths demonstrates the principles of slowing the flow … with urban SuDS using a specially built model, and a watering can.
Amanda McDermott presents on why and how urban SuDS can be used to Slow The Flow – at Work, at Home, at School, and in Public Spaces.