Hardcastle Crags

Hardcastle Crags, our local National Trust site here in Calderdale is an area of outstanding natural beauty and the home of Slow The Flow’s most successful project on the ground to date.  

Our teams of volunteers have built in excess of 520 woody leaky dams with another 100 built by local contractors in harder to reach locations around Hardcastle Crags.  These comprise a series of leaky dams blocking water courses that pass through relatively level areas of woodland. The water pools behind the dams and slows the flow.   These interventions mimic the natural environment by pushing excess water onto the forest floor, slowing its flow to the main river channel. 

This helps to reduce the height of the flood peak in our towns and villages further down the catchment, at Hebden Bridge, Mytholmroyd and beyond.

These leaky dams also provide additional environment benefits like diversifying natural habitats for animals, insects, flora and fauna. 

Volunteers have also created several large areas where water will be temporarily stored during a storm. 

These interventions mimic the natural environment (beavers, etc.) to slow the flow of rain water from the hillsides by pushing excess water onto the forest floor, slowing its flow to the main river channel. This helps to reduce the height of the flood peak in our towns and villages further down the catchment, at Hebden Bridge, Mytholmroyd and beyond. For more information see here .

Our dedicated teams of volunteers have worked tirelessly every month to build in excess of 10 / 12 new dams every month and there are plans to continue this work here for many years to come.

We have great fun, contributing to flood prevention in the Calder Valley, whilst enjoying the outdoors – if you would like to join us, get in touch!

Future volunteering dates can be found on our calendar. (Due to covid our volunteering is on hold, we will update as soon as we can.)

Hardcastle Crags is also the home of our river level monitoring project which will help us to understand the impact our work is having, and provide data on river levels throughout the area to allow residents to react before and during a storm. The monitoring comes in many forms and more information can be found here.

Leaky Dams in action! Watch the pools form (especially in the top left) as the snow melts.

For more information on what we are doing at Hardcastle Crags,  see our blog posts below or visit our blog page.

A Natural Flood Management Pilot Project at Hebden Water and Crimsworth Dean Beck, Hardcastle Crags, Hebden Bridge, West Yorkshire

Helping Ourselves (Part 2); The importance of river surveys and a pilot project for Hardcastle Crags

Engineered Leaky Woody Dams (WeLD’s) on Rock Stream Beds

Part 2. Engineered Leaky Woody Dams (WeLD’s) on Soft Soil Stream Beds

Our river surveys have been an integral part of getting to this stage – find out more about them