SCI has funding, via the Scottish Government’s Nature Restoration Fund, to investigate how erosion scars on the Allt Mor, a tributary of the Spey, contribute to sediment build-up and flooding in Kingussie. We are working alongside stakeholders and the community to explore potential solutions to help reduce flood risk and enhance biodiversity along the river. Together we are hoping to find a widely supported solution and identify how this might be implemented in the future.
During 2025 we have been collecting information on the issues and potential solutions, including reviewing previous studies and commissioning new ones such as a herbivore impact assessment and an in-depth report from CBEC eco engineering. We have also been engaging with important stakeholders such as Pitmain and Glenbanchor Estates, Highland Council and Kingussie Community Development Company, and most importantly, consulting with the local community.
Community Consultations:
We held a successful consultation event in Kingussie on the 24th of September, open to all members of the public, and due to feedback received, have since been working with:
- Pitmain & Glenbanchor Estates to understand their peatland restoration programme, looking for opportunities to prioritise work to slow the flow of water in the Allt Mor catchment.
- Community members and Pitmain & Glenbanchor Estates to explore land use history in the Allt Mor catchment, such as historical drainage and changes in grazing pressure.
- Highland Council to look into dredging and ways it could be improved for both people and the river.
We have also been reviewing other potential solutions suggested during our first public consultation event and working with stakeholders to assess their feasibility.
Next Consultation Event: December 2025
We will be holding a second consultation event on Wednesday 10th December from 7 – 8:30pm at Talla Nan Ross in Kingussie to update on progress, including on our investigations into peatland restoration, historical land use and dredging, as well as the CBEC report. We will be asking for views, opinions as well as discussing possible next steps.
Location: Talla Nan Ros (Main Hall), King Street, Kingussie, PH21 1EH
What3Words: https://w3w.co/thickened.parent.both
The venue is fully accessible and refreshments will be available.
If you can’t make it but would still like to contribute, an online feedback link will be available after the event and shared on our website and social media.
Summary of the investigation so far
The Allt Mor is a steep fast flowing river rising in the Monadhliath before becoming the Gynack Burn, flowing through Kingussie and joining the River Spey.
Kingussie has been affected by flooding from both the River Spey and the Gynack Burn, with flooding records going back almost two hundred years.
Low bridges through the town, particularly the railway bridge and the High School bridge, leave Kingussie vulnerable to flooding from the Gynack during heavy rainfall events. Sediment builds up at these bridges, reducing space for water to pass through and causing water to flood out onto the road.
Research to date, primarily commissioned by Highland Council, recognises that sediment build up is the main cause of flooding and different forms of sediment management have been suggested. Currently, the following systems are in place to try and tackle the issue:
- Dredging of the lower Gynack Burn
- Kingussie Flood Alleviation Channel from the Allt Mor/ Gynack into Loch Gynack
- Sediment trap to catch sediment above Pitmain Lodge (requires dredging)
However, dredging is only ever a temporary measure that must be repeated, is expensive and unsustainable, with negative impacts on the river and wildlife. Therefore, our key question is:
Can we / should we do anything to help reduce sediment input to the river upstream by reducing erosion?
We are investigating the possibility of stabilising the erosion scars, while also restoring natural river processes and enhancing the habitat quality along the river. Climate change is increasing the frequency and intensity of rainfall and so it is important to build as much resilience as possible into areas already vulnerable to flooding.
Dredging will likely be required going forward, even if sediment input to the river is reduced, however the hope is that the frequency would be reduced.
Continue reading to find out more about our investigation.
Research to date: what do we know?
There have been 11 studies into flooding and sediment management on the Allt Mor/ Gynack Burn since 1992, commissioned by various organisations including the Highland Council and Network Rail.
A few key studies* are outlined below, along with key findings relevant to this investigation:
- Report on flood mitigating schemes (Robert H. Cuthbertson & Partners Consulting Engineers, 1992). Recommended constructing a sediment trap along with dredging to increase capacity of the Gynack Burn.
- Geomorphological Appraisal (JBA, 2007). Lots of recommendations including reducing sediment input at its source, installing sediment traps and diverting water elsewhere but ultimately continued dredging was sighted as the most economically viable option.
- Kingussie Flood Study (AECOM, 2012 & 2015). Flood diversion channel using Loch Gynack for flood water storage recommended.
- Allt Mor/ Gynack study (CBEC, 2023). A concept to stabilise the erosion scars on the Allt Mor was developed but further work required to establish viability and potential impact.
- Fluvial audit, sediment budget and optioneering study on the Lower Gynack (CBEC, 2024). This study looked at the movement of the sediment in the river, where it comes from and where it goes, as well as ways to reduce flood risk in both the short and longer term.
Several mitigation options have been suggested and implemented over the years including dredging the Gynack in Kingussie, constructing the Kingussie Flood Alleviation Channel to divert water from the Allt Mor into Loch Gynack and digging a sediment trap upstream of Pitmain Lodge. Ongoing regular maintenance is required for these systems to work due to the vast sediment supply from upstream.
Following these interventions, the Spey Catchment Initiative commissioned CBEC eco-engineering to do a walkover survey in 2023 along the Allt Mor and assess options to reduce sediment input to the river upstream of the sediment trap. Highland Council subsequently commissioned CBEC to conduct a fluvial audit, analysing sediment supply, transport and deposition along the lower four kilometres of the Gynack Burn in 2024. Options to reduce flooding in Kingussie were also included. The report found that the majority of sediment is coming from the upper catchment, as expected, however it is described as ‘excessive’.
*If you are interested in reading any of the 11 studies, they can be accessed on request from the Highland Council.
The problem: Allt Mor Erosion Scars?
Extensive active erosion scars on the Allt Mor cutting into glacial drift material (mounds of gravel, sand, cobbles, boulders, clay, silt) are suppling large volumes of sediment to the watercourse, with consequent implications for biodiversity and flood risk downstream.
A healthy river needs three things: water, sediment and organic matter. Erosion is a natural process, especially in steep upland catchments, however in this instance the erosion is heightened by a lack of riparian vegetation to help stabilise the riverbanks and the steep angle of the slope, which further reduces slope stability.
Currently, the river is carrying an incredibly large volume of sediment in spate conditions and this is deposited as the gradient flattens out lower down in Kingussie, blocking bridges and causing flooding.
Climate change is also increasing the frequency and intensity of extreme rainfall events, exacerbating the problem. The aim is to look at reducing erosion, rather than halting the process entirely, while exploring opportunities to enhance biodiversity, increase resilience and slow the flow of water from the hillside above Kingussie.
What have we done so far?
The following baseline surveys are planned/ have been undertaken as part of our investigation to understand the current conditions along the Allt Mor:
Ecological surveys which are part of our investigation:
- Herbivore Impact Assessment
- Vegetation mapping (National Vegetation Classification)
- Electrofishing
- eDNA
- Freshwater Invertebrate Sampling
- Protected Species Survey
Technical surveys which are part of our investigation:
- Fluvial audit (analysing areas of sediment supply and sediment accumulation)
- Topographic survey
The results from these surveys will help to build a detailed picture of current issues on the Allt Mor and help to determine the best way forward.
Could stabilising the erosion scars be part of the solution?
The main issue highlighted in all 11 previous studies into flooding in Kingussie is sediment build up and the erosion scars currently provide an almost inexhaustible supply of sediment to the Allt Mor.
The four most severe erosion scars on the Allt Mor are eroding due to the steep nature of the slope, the river at the bottom and rainfall from above. It is estimated that these erosion scars supply 60 – 70% of the total sediment in the river.
Due to high slope instability and increasing rainfall intensity, natural erosion scar stabilisation through vegetation establishment is unlikely.
As a result, we working with partners to assess the possibility of reducing the slope angle of these erosion scars, which will increase slope stability and reduce sediment input to the river. Along with livestock exclusion, this could enable vegetation to recolonise the slopes providing further stability.
Early indications suggest that while this could help to reduce flooding, erosion scar stabilisation could take up to 10 years to have a positive impact downstream due to the large volume of sediment already in the river.
We are keen to share our findings so far with the community in Kingussie to see what people think.
Investigation Partners
Spey Catchment Initiative
Project Lead
Nature Scot
Investigation Funder
Pitmain and Glenbanchor Estate
Land Owner
CBEC
Lead Consultant
This investigation is also being supported by a number of organisations who have provided their expertise in carrying out surveys. These include:
- Spey Fishery Board
- University of the Highlands and Islands
- Adoxa Ecology
- Tracks Ecology
