The £1 million Connecting the Culm project commenced in January 2019 and will run until June 2022, funded partly by a 60% contribution from Interreg and the remainder by partners. The project has been developed by a partnership of organisations including the Devon County Council, Environment Agency, Mid Devon District Council and National Trust and is led by the Blackdown Hills AONB.
The Challenge: Along the Culm’s 40km length, from its headwaters in the Blackdown Hills in Somerset to its confluence with the Exe in Devon, the river generates several linked problems:
- There are hundreds of properties at risk from flooding along the length of the river; the Culm’s flood peak also magnifies the flood peak of the river Exe as it enters Exeter, increasing the risk to properties in the city and also affecting the national rail network
- The whole length of the river Culm is failing water quality targets because of diffuse and point source pollution and high sediment loads. The river also flows directly into and affects the quality of the Exe Estuary (an SAC/ SPA/ Ramsar Site)
- The river and its floodplain run through major development areas proposed in the Greater Exeter Strategic Plan (that also includes the planned 5,000-home Culm Garden Village); and planners and local communities must try to create flood-resilient developments
- Initiatives such as Catchment Sensitive Farming and Upstream Thinking, that work with landowners and communities to secure improvements to rivers and riparian land, have not been applied on the Culm.
- The headwaters of the catchment support important but degraded priority wetland mosaic habitats including spring line mires; these could act as natural sponges, but their function has been reduced by changes in agricultural practice
- The headwaters also support endangered populations of protected and priority species, including the white-clawed crayfish, which are threatened by poor water quality and the invasive American signal crayfish.
- Much of the central part of the catchment lacks areas of priority habitat, meaning ecological connectivity is lost through the catchment apart from the core river itself.
- The river is rich in heritage value, notably a chain of historic water mills with their associated leats, but these are under threat and little understood.
- Engaging the public on issues of pollution and wildlife loss in their communities can be difficult, especially when damage may have been over a long period and as a result of activity by members of that community
Many of these problems have arisen because the river has often been treated by policy-makers, land managers and individual residents as a series of disconnected units with disparate functions, leading to poor decision-making and land management.
The Opportunities: These problems need to be tackled, and the Culm has some positive features that make this feasible:
- Its compact scale means that an integrated, whole-river approach can be readily adopted
- Previous projects working with communities in the Blackdown Hills have created a strong foundation of engaged volunteers and a good sense of connection to the river Culm
- The urban development of the Culm Garden Village requires imaginative solutions to avoid exacerbating existing problems and create a desirable green settlement, and the developers are keen to adopt a catchment-wide approach
- A key landowner on the floodplain – the National Trust – is keen to naturalise its landholding along the river and work with stakeholders to achieve this
- Collectively, residents, land managers and planners need a better understanding of the river as a single ecosystem that depends upon multiple inter-related decisions and influences by people in the catchment
- Innovative nature-based solutions and techniques are being developed to help resolve the problems of flooding, water pollution, soil erosion and biodiversity loss
The Project: Connecting the Culm has formed a partnership to take a coordinated approach to these problems. The project aims are to:
- Make the Culm river and its floodplain more resilient to flood and drought, using nature-based systems and approaches
- Improve water quality and biodiversity on the Culm (and consequently in the Exe and its estuary)
- Encourage people living in the catchment to feel more involved in decision-making and support the use of nature-based solutions to manage water
We will do this by:
- Improving local people’s understanding of water management techniques and the function of the river / catchment ecosystem as an integrated whole
- Creating new opportunities for people to collaborate in addressing water management, leading to communities cooperating more effectively to address the challenges created by climate change
- Installing tangible demonstrations of appropriate nature-based solutions to build confidence, encourage cooperation and raise aspirations – these will be replicable and provide solutions that can be rolled out by the community
- Developing a Blueprint for the Culm that will be the masterplan for the whole catchment for the next 25 years, co-created by the people that live and work within the catchment and the organisations that have a role in the area.
Our Approach: Our approach is to work throughout the catchment, engaging with people affected by, or playing a role in, the river and its tributaries. A multi-agency team will deliver the project, comprising specialists in natural flood management, community engagement and biodiversity. We will:
- use scenario-forecasting to explore the potential impacts of climate change on the catchment; ecological network mapping overlaid onto hydrological studies will highlight key areas of multiple benefit and best added value
- show how innovative nature-based techniques can help mitigate impacts and adapt to the new circumstances;
- involve people in shaping a new governance solution for the catchment –the Blueprint for the Culm
- We will create three Demonstration Zones where the new techniques will be tested and demonstrated:
We will create three ‘demonstration zones’ where the new techniques will be tested and demonstrated:
The headwaters zone – restoring the mires where the river and its tributaries arise whilst conserving the remnant population of white-clawed crayfish
The Culm Garden Village zone – where the first steps in developing a new town will be to construct flood management infrastructure on surrounding land, shaped by a catchment-wide hydrological study
The floodplain zone – rewilding the floodplain, working alongside land managers and creating new trails and ecotourism facilities
Each zone will test a range of nature-based interventions, shaped by its landscape and history, its communities and their aspirations. Examples include:
- Restoring hydrological function to spring-line and valley mires, providing a range of ecosystem service benefits including flood attenuation and carbon storage in peat rich soils
- Damming streams and drainage channels using natural woody debris to create attenuation ponds and silt traps, reducing flood peaks and reducing downstream sedimentation
- Innovative flood alleviation features on land associated with new, large developments, showing how multi-use green infrastructure is deliverable, unlocking significant added benefits
- Planning resilience into new developments including allowing for the spread of beavers from the neighbouring River Otter catchment
- Coppicing and laying bank-side trees to imitate beaver activity, improve water oxygen levels and reduce livestock disturbance of the river bed
- Reconnecting the river to its floodplain and restoring more natural floodplain function on intensive agricultural land, by re-creating floodplain attenuation features, restoring wetland habitat and unlock other ecosystem service benefits including enhanced access and recreation
- Restoring agricultural soils to enable them to achieve their natural hydrological function
- Restoring historic leat systems and ponds that hold flood-peak waters and generating renewable electricity at their outlets
- Adopting community based and driven solutions to tackle the challenges faced by the river and its floodplain including supporting community land trusts, collaborations of small-scale landowners and community focused interventions