Fingerprinting results signpost interventions in Troutbeck

Background

Earlier this year South Cumbria Rivers Trust (SCRT) introduced the Windermere Sediment Fingerprinting Project taking place in the Troutbeck valley. The results are now in.

In case you missed it, ‘sediment fingerprinting’ is a method that can be used to identify the main land use types acting as sediment sources into a river. Research has been carried out across the country to develop this technique into a new, fast-track process that can be used for catchment management. However, data was lacking from landscapes like those seen around the Windermere catchment. Troutbeck was selected by Love Windermere Partners and Natural England as a site to address this, since the river is a relatively straight run through from source to mouth set within a separate valley with high rainfall and mixed land use. Thus, making Troutbeck ideal for this type of research.

Troutbeck itself is an important fish spawning habitat, so minimising sediment inputs is important to help safeguard clean spawning gravels and prevent negative ecosystem impacts. Additionally, sediment input into lakes can be a potential source of additional nutrients, so we wanted to investigate where Troutbeck sediment was coming from to understand where we needed to focus efforts as a Partnership.

What we found

Following training delivered by Rothamsted Research, six dedicated SCRT volunteers collected 79 soil samples from a range of land use types (including footpaths, grassland and woodland) from around the Troutbeck valley. At the same time, SCRT installed a sediment trap below Troutbeck Bridge to capture suspended sediment from the river. The soil and sediment samples were processed and analysed by scientists at Rothamsted Research. The results indicate that the two most important sources of sediment to the Troutbeck are footpaths or unpaved tracks and channel banks. Sediment was coming from other land use  types too, but in much smaller quantities.

 

What can be done

Footpaths, tracks and bridleways are a common feature across the Lake District, with millions of people accessing the landscape each year, including farm vehicles, walkers, cyclists and more. Footpath erosion is a known issue tackled by programmes including Fix the Fells, while agricultural tracks can be addressed with support from Catchment Sensitive Farming (CSF) and other programmes. If anything, the results show the need to continue supporting these types of programmes to help protect freshwaters and reduce impacts on the wider environment. Sediment trapping itself can be incorporated into other types of interventions to deliver multiple benefits, these include sustainable drainage (SuDS), natural flood management (NFM) and amenity improvements.

Channel banks are the areas close to the river where factors such as river erosion, livestock poaching, and channel engineering affect sediment dynamics. These inputs can be managed by features like exclusion fencing, buffer strips and riparian planting, which can help to reduce erosion, trap sediment and bind river banks together. The restoration of natural river behaviour, including reconnecting the river to its floodplain, can also deliver multiple benefits including trapping sediment, supporting floodplain productivity, and reducing flood risk downstream.

Funded through a collaborative agreement with Catchment Sensitive Farming (CSF) (Partnerships) this project brought together partners including the Environment Agency and Rothamsted Research. South Cumbria Rivers Trust (SCRT) led volunteer coordination, supported by local representatives from CSF and the National Farmers Union (NFU).

This work supports Love Windermere’s mission to improve the health of the lake while safeguarding it for communities, wildlife, and visitors. Project partners will now use this research to help inform land management related action, including catchment walkovers, engaging local land managers on options and delivering sediment reduction interventions.

If you’re interested in finding out more, contact SCRT for further information; info@scrt.co.uk