Why Rehabilitate Malham Beck?
At first glance Malham Beck, downstream of the village of Malham and next to the Pennine Way, may appear a lovely little stream with (mostly) crystal clear water from its limestone origins. However, the channel in its current form is almost entirely artificial, historically realigned to run overly straight (especially parallel to the Pennine Way) and then pinned against a field boundary with limestone boulders as walling to prevent it moving back to where it would rather be!
Straightened channels are shorter and steeper and so the water flows faster, contributing to issues like flooding and accelerated erosion downstream. The artificial ‘banks’ do not provide the same dynamic, vegetated margins of a river, nor allow for erosion and deposition and hence some movement over time, thereby starving the channel of new gravel. The result is a rather uniform channel of relatively constant proportions, lacking the physical diversity to support the biodiversity that it should.
What are the aims of this project?
To reinstate more natural and dynamic processes, allowing the channel to better reconnect with its floodplain and thereby rewet the adjacent meadows to rekindle this vital habitat. A more sinuous course and connected floodplain will slow the flow, providing more temporary storage of water within the catchment under higher rainfall events, and reducing the pressures of spate flow on the existing channel bed and aquatic denizens as well.
What has this project achieved?
Working with full collaboration of two landowners, the historic ‘shackles’ on channel are being removed and the beck is effectively restoring itself slowly but surely:
- Walling in the true left bank (looking downstream) has been removed at key locations to allow the beck to erode into the bank and reinstate a more meandering (wiggly) course.
- Diseased ash trees have been felled and the material laid into the channel to encourage flow to the points where walling has been removed, again to increase sinuosity.
- The walling stone has been reintroduced to the existing channel to partially raise the bed in key areas, allowing better reconnection with the floodplain under high flows.
- Livestock density and management has been changed in two different ways. In one field, low density of hardy breeds (both cattle & sheep) are being used to manage the wetter meadows to promote floral biodiversity. In another, where there was no existing tree cover, livestock has been completely excluded to allow both tree and herb diversity to recover – once re-established, it may be possible to reinstate a sympathetic grazing regime.
- A small number of native tree species have been planted to kick-start some shade and cover, and to bolster local biodiversity.
- A baseline survey of brown trout population structure has been conducted and will be undertaken annually to assess change.
A summary of the project so far has been put together in video format, watch here: https://www.youtube.com/watch?v=HDvsA_b12zo
Who is involved?
The project has been conceptualised and delivered by the Wild Trout Trust (WTT) as part of its ongoing contribution to the Upper Aire Project, with the full cooperation and support of the two landowners. Further match-funding was awarded from The Environment Agency Fisheries Improvement Programme, Yorkshire Water’s Biodiversity Enhancement Programme, and the West Yorkshire Salmon & Trout Conservation UK. It complements similar habitat work led by WTT in partnership with National Trust on Malham Beck upstream of the village, as well as downstream on the Aire at Hanlith and Airton, as well as weir removals at Newfield Grange and Coniston Cold.
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