Mapping Explained
| Layer title | Datasets | Implications for NFM |
|---|---|---|
| NFM Potential 1 |
Within both Landscapes for Water and Priority Catchments for NFM. Outside all ecological datasets. |
Likely benefits from implementing all types of NFM which slow or temporarily store water flow in these areas, based on modelling work. Also prioritised for tree planting by White Rose Forest to help reduce flood risk. |
| NFM Potential 2 |
Within Priority Catchments only. Outside all ecological datasets. |
Likely benefits from implementing all types of NFM which slow or temporarily store water flow in these areas, based on modelling work. |
| NFM Potential 3 |
Within Landscapes for Water only. Outside all ecological datasets. |
Prioritised for tree planting by White Rose Forest to help reduce flood risk. |
| NFM Potential 4 |
Sites of Special Scientific Interest. Excluding Ancient Woodland. |
Moorland restoration such as gully blocking and vegetation renewal often possible. |
| NFM Potential 5 | Ancient Woodland, includes areas within Sites of Special Scientific Interest, Local Wildlife Sites and the Wildlife Habitat Network. | NFM within ancient woodland may include woodland management, leaky dams, fascines. Ecological assessment always required and NFM may not always be possible. |
| NFM Potential 6 |
Wildlife Habitat Network. Excluding Sites of Special Scientific Interest, Local Wildlife Sites and Ancient Woodland. |
Mainly grassland which will probably exclude tree planting but other measures may be possible such as soil aeration, bunds, attenuation basins. Ecological assessment always required and NFM may not always be possible. |
| NFM Potential 7 |
Local Wildlife Sites. Excluding Ancient Woodland. |
Ecological assessment always required and most NFM unlikely to be possible. |
| NFM Potential 8 | Outside all datasets. | No known ecological constraints for NFM, areas outside of current priority sub-catchments. Land where attenuation ponds, scrapes, hedgerow planting could be beneficial. |
How to interpret the Map
- The purpose of the NFM opportunity mapping is to identify areas where various types of NFM initiatives will have the greatest impact and ecological impacts are likely to be low. This work is to facilitate the implementation of NFM as set out in the Calderdale Flood Action Plan.
- NFM Potential 1, 2 and 3 are prioritised by catchments identified by Thomas Mackay modelling (a desk based hydrological review to assess potential for NFM) and areas targeted by White Rose Forest for tree planting to help reduce flood risk and do not overlap with any of the ecological datasets used.
- NFM Potential 4, 5, 6 and 7 are all based on ecological datasets. These areas offer potential for certain types of NFM initiatives. However, it is important to note that they also present potential ecological constraints which are likely to restrict NFM options.
- NFM Potential 8 are areas where the land is not currently prioritised by catchment modelling for NFM and no ecological constraints are currently identified.
Next steps
The opportunity mapping is at a large spatial scale. The datasets used do not include assessments for the viability of NFM in those areas. So, the implications for NFM can only be inferred.
Further assessment of the suitability and benefits of NFM, as well as ecological surveying is required before any NFM initiatives can be taken forward. These can include:
- Planning permissions.
- Consents in relation to watercourses (from the Environment Agency or local authority). For more about this, please visit: https://eyeoncalderdale.com/natural-flood-management (Eye on Calderdale).
- Assessments around historical/archaeological sites and detailed engineering studies, as well as botanical/fungal/bird/other surveys.
More information is available on the 'NFM What consents do I need?'.
Datasets
This has been achieved through the use of the following datasets:
- Priority Catchments. Boundaries of sub-catchments in upper Calder valley where the greatest potential benefits from NFM are likely based on modelling work by Thomas Mackay. More modelling work is currently being funded to investigate what is required to scale up NFM across the whole Calderdale catchment area which will also further inform locations likely to benefit from NFM measures.
- Northern Forest Landscapes for Water (L4W). Areas where White Rose Forest/Northern Forest are focusing their tree planting efforts to help reduce the risk of flooding but also deliver wider ecological benefits such as improved water quality, biodiversity and recreation.
Ecological Datasets
- Sites of Special Scientific Interest (SSSIs). Nationally protected land for features such as wildlife and geology. Almost all of the SSSIs are also designated as Special Areas of Conservation (SACs) and Special Protection Areas (SPAs) which are of European importance.
- Local Wildlife Site (LWS). Land of ecological importance at a West Yorkshire scale designated according to scientifically-determined criteria. They represent critical wildlife refuges and form key components of the Wildlife Habitat Network. Land likely to meet the criteria but not yet designated is also included.
- Ancient woodland. Areas of woodland that have persisted since 1600.
- Wildlife Habitat Network (WHN). A network of ecological corridors which link sites of biodiversity importance and provide continuous stretches of permeable habitat that can be utilised over time by species moving between core areas and should be the focus of biodiversity conservation. The Calderdale WHN methodology document provides more information.
Other datasets
There is scope to incorporate additional datasets, such as:
- sites ready for NFM that lack funding;
- or current land use across the Calder Valley.
This is open to suggestions from partners.
To added these:
- Include as an additional layer on top of existing layers which can be toggled on or off.
- Cut out of existing layers and mapped alongside the existing colour scheme.