Slow The Flow NFM and SuDS Opportunity mapping in Mytholmroyd, West Yorkshire.


At Slow The Flow, we want to encourage and empower people and organisations to take action on their own property and land whether that is private or public-facing.  Many small‑scale interventions, taken together, would result in a significant amount of water being temporarily stored, or attenuated, during storm events.  This would help to reduce peak flows which, together with wider catchment management and traditional flood defences, would contribute to reducing the scale and damaging effects of flood events.

This new project will give geographic detail, and more specific advice on each proposed location, on realistic implementation of rural NFM and urban SuDS in the area illustrated below in Mytholmroyd.

It contributes to our work with Calderdale NFM Operations Group partners to address actions in the Flood Action Plan, including ‘mapping NFM opportunities’, which is an action in the plan.

This pilot project has been kindly grant funded by Hebden Royd Town Council and the Community Foundation for Calderdale.


The mapping will identify realistic locations on a field / street level of detail, where residents, businesses and organisations in Mytholmroyd can contribute to flood alleviation through natural / sustainable interventions, and give indications as to what interventions might be appropriate in those locations, such as:

  • Rain garden
  • Green roofs
  • Water butts
  • Swales
  • Ponds
  • Detention basins
  • Tree planting

Urban locations might include:

  • public highways
  • schools
  • parks
  • other Local Authority / publicly owned sites
  • commercial properties / car parks
  • residential gardens/driveways
  • including opportunities for neighbours working together
  • development sites identified in local plan

Rural locations might include:

  • Local Authority owned sites
  • woodlands
  • farm land
  • fields
  • rural private property
  • development sites identified in local plan
  • including opportunities for neighbours working together

The exercise is informed by OS and Google mapping, teamed with local knowledge, and on site ground-truthing exercises. It includes locations where retrofit is possible; to inform and inspire any future renovation works.

Publicly available mapping, hosted on the STFC website, will encourage and enable the suggested rural NFM and urban SuDS actions.

It will not only act as a guide and inspiration where landowners had not previously considered that they are able to help, but will be available in such situations as:

  • A reference tool for use when considering any new or retrofit build projects
  • Ensuring appropriate allocation of grant funding (for example future rounds of CMBC’s NFM grant fund, or other funds allocated to flood alleviation)
  • An influence, to assist in implementing the emerging local plan, when developing and assessing planning application.
  • Potential to combine with other mapping such as CMBC’s online mapping portal, overlaying this information with layers such as designations, local plan information etc.
  • Assisting CMBC’s NFM officer in allocating resources to best effect


Northern Mytholmroyd has been used for the pilot, partly because we consider that there are interesting opportunities available, and partly due to the significant urban realm regeneration work being undertaken, including a developing neighbourhood plan which incorporates a desire for inclusion of NFM and SuDS.

Our mapping should be a useful influence to enable future works to properly consider NFM and SuDS, potentially encouraging and enabling grant funding applications.

We hope ultimately to extend the opportunities mapping work to cover a wider area.

1 thought on “Slow The Flow NFM and SuDS Opportunity mapping in Mytholmroyd, West Yorkshire.”

  1. Hi

    I’ve been wondering if an exercise to may the hydrological impacts of the extensive paths/track system of the hillside would be worthwhile. The Upper Calder Valley has a very dense network of such routes and , depending on their location/slope orientation etc, they can either act as barriers to water or additional channels – as we have seen in past storm events. The extent of any associated drainage with such routes ie ditches/culverts etc will also be important.

    It would make a good academic project for someone and data sources are available ie topographical data + digital rights of way maps so modelling should be possible.

    I work for Natural England and climate change adaptation/mitigation is part of our work. We also hold numerous data sets which I could check for availability if wished.

    let me know if you’d like to discuss further

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