River Otter RRC Member Site Visit

Exceptional weather met 16 RRC members, staff and board for the recent site visit to the River Otter in Budleigh Salterton, Devon. Mike Williams from the Environment Agency provided us with an informative and fascinating tour of the 3 mile length of the Lower Otter restoration project, which is nearing completion in the coming months. The main aims of the project are to mitigate the future likely impacts of climate induced sea-level rise in the area (estimated to be 1.2m) by; reconnecting the River Otter to its floodplain, safeguarding local settlements and public rights of way from floods and providing 55Ha of new intertidal habitat, including mud flats and saltmarsh by allowing the tide access to disconnected areas. As with all human induced changes, historical modifications installed on the Otter estuary require vital management and maintenance and increasingly the changing climate is making it more costly and difficult to justify this. Recently highlighted by the 2018 floods which overwhelmed the anthropogenic drainage system and almost destroyed the old embankment completely.

1. Standing on the current embankment, created in 1800’s reclaim land for agriculture, among other uses.

Previously, the RRC had visited the site during the 2019 AGM, so it was great to be able to see the progress made from the planning, pre-works phase of the project – check out the previous blog post here. This ambitious and multi-faceted project has been the culmination of almost 20 years of planning and hard work and Mike’s knowledge and passion for its delivery and many benefits were clear. The European Union’s, Promoting adaptation to Changing Coasts (PACCo) were the main funding partner involved in the project, alongside the Environment Agency and Clinton Devon Estates.

The history of the Otter estuary has been remarkably well documented, by Clinton Devon Estates and their predecessors, as far back as the 1800’s. In 1809-1812, James Greene and Lord Rolle executed their cutting edge land reclamation plans by building embankments that cut off almost three-quarters of the original estuary extent and draining the floodplain, to provide more agricultural land for local tenant farmers. Other engineering works carried out over the 19th and early 20th century included; building aqueducts to carry tributaries over the floodplain and culverting others, creating a main trunk drain to convey water and sediment straight out to sea, creation of a refuse tip and converting an area into a cricket pitch for local people. All of these modifications adversely impacted the natural ability of the river and its floodplain to support biodiversity and attenuate flood water so that upstream, local settlements (e.g. Newton Poppleford and Otterton) have been increasingly affected by flooding incidences during high rainfall episodes, particularly compounded over high tides. With pre-modification estuary data and plans available, it was possible to see how the estuary could be returned to a more natural state by removing many of these anthropogenic structures, giving the river back its floodplain and allowing natural processes space and time to reinstate riverscape functions.

Many obstacles and challenges were overcome during the planning and implementation of this project. Below is a summary of some of the main issues. The context of the land-use and designations of the site provide the back-drop to the complex and diverse nature of the consideration needed during planning and implementation. The River Otter has numerous conservation designations including SSSI’s for saltmarsh and mudflat habitats and is situated in the East Devon AONB. Adding 55Ha of saltmarsh and mudflats to the current estuary offering of 33Ha, was of obvious benefit, however care was taken to ensure relocation occurred and limited disturbance of protected species (including dormice, beaver, bats and ring tailed plover) during heavy machinery works (photo 3). We were surprised to learn that some species are recovering already, despite heavy plant operations ongoing on site; sightings of the rare black tailed godwit, for example, increased from 6 in February 2002 to 106 in 2023.

2. Local wildlife has apparently had very little adverse effects during construction, showing careful construction working with nature is possible.

3. Current previous floodplain with heavy machinery building new footbridge for the South West Coast path and reconnecting the floodplain.

The shingle bar, located on the sea front, creating a narrow 15-20m outlet for the mouth of River Otter is designated as the UK’s only natural world heritage site and has changed very little over last few hundred years. Protecting the integrity of the shingle bar is an important aspect of the project. Buried within the bar is a South West Water owned, sewage outfall pipe which had to be relocated as part of the project, using directional drilling to future-proof the asset and mitigate for predicted change as natural processes reshape the estuary. This was a particularly costly addition to the project, but vital to secure waste management for the local population. It will be interesting to see the changes that will occur at the mouth of the estuary with the predicted tidal prism to be 2.5 times higher than the current, increasing velocities and leading to erosional processes in both lateral and vertical directions. Erosion will be monitored at the shingle bar and water levels monitored via surface radar at various sites further up the estuary.

Local amenities, including the cricket club and numerous public rights of way (the protected SW coast path travels along part of the embankment) were protected and in some cases relocated. The cricket club was relocated to another local area and tenant farmers were compensated with new farmland located nearby.

4. New road bridge to replace the regularly inundated previous road

Construction of a new road over the floodplain, complete with raised bridge will be affected less frequently by flooding than the original road (photo 4). It had recently opened 6 weeks prior to our visit and locals were using it to access farms and local businesses on the other side of the river. A new car-park for locals, who asked for parking as a priority, due to the high number of visitors to the area, particularly in summer is nearing completion also. The road backs onto the old refuse tip that has been closed for 40 years or more. Contaminated ground examinations using boreholes were carried out to ascertain the level of pollutants (mostly heavy metals, oil and small amounts of asbestos). To avoid any potential release of pollutants the tip has been re-capped on the top and sides. No pollution reports have historically been noted at the site and the decision to plant floodplain forest species (such as; hornbeam, birch, rowan, wild cherry etc) and grasses will provide further stability, creating more habitat for birds and other species. Hedging has been planted on either side of the road for dormice and other hedgerow species.  Rip rap and shingle was imported to the western edge of the tip, at the base of the road bridge to further stabilises the refuses tip from erosion (photo 5).

5. Rip rap to protect the refuse site from erosion and tree planting. Note: Water level monitoring station installed on road bridge.

Dealing with the large number of public footpaths, including the nationally important South West Coast path, was no mean feat. Entirely removing the old embankment to allow full reconnection of the floodplain, would have involved re-routing and closing the footpath. However this would have led to a public enquiry that could potentially have derailed the project. So the decision to remove only part of the embankment and raise the old footpath via a footbridge over the gap, will allow improved access for visitors and locals and also future-proof a nationally important route against rising sea levels (photo 6).

6. 25m steel and concrete footbridge supports to replace and future proof the section of SW coast path is set for removal.

Visitor information boards and viewing platforms are stationed along the length of the site (photo 7), including one on the bridge to encourage wildlife spotting and educate and inform the public. Allowing people to learn about rivers and associated features and wildlife brings agency to communities and reconnects people with their environment. So vitally important to preserving and improving our natural spaces and functions for future generations. The bridge is currently being constructed on site and the 25m concrete and steel supports are in place. The embankment breach will be the last phase of delivery.

7. Viewing stations and information boards provide visitors with wildlife information and hides.

Despite some strong local opposition to the project, via a range of communication channels and series of events the local community were informed of the benefits of the project and concerns were addressed over many years. The project began in earnest in September 2021 and now local people are beginning to realise those benefits in 2023; having roads and footpaths accessible year round, improved biodiversity and opportunity to experience nature and the reduction of flooding, which will be realised in full during the final phase of the project. It is really encouraging to see what can be achieved with expert communication and understanding how best to address individual and community concerns in the face of change. Clinton Devon Estates will take over management of the area when works are completed and it sounds like their input to the project and forward thinking ethos has been important to the success of the project. Future risks posed by climate change to this local community have been reduced significantly and this scheme will be a guiding light for other coastal protection projects in development around the UK and EU.

Standing on the embankment looking out over the current estuary, which is impacted from high levels of sediment accretion degrading the mudflats and affecting food sources for wading birds, you could imagine the embankment breach, linking up the newly made tidal creek network in the old floodplain with the narrow, straight channel seen in photo 8. Nature setting to work, creating a new riverscape. Geomorphic processes beginning to take over, eroding the high banks of the current islands and forming new channels through the mud flats and saltmarsh encroachment. I’m excited to return post-breach to discover how the riverscape and intertidal habitat offering has changed – watch this space for future RRC visits to the area!

8. Site of embankment breach, looking towards the mouth of the estuary. The modified tidal creek will be left to re-naturalise post-breach. Note: bunds are in place due to recent embankment strengthening works, following failures during floods that allow footpath access.

For more information and updates on the project please visit: https://www.lowerotterrestorationproject.co.uk/ and https://www.pacco-interreg.com/