- 31st January 2020
- Posted by: Joanne Woodhouse
- Category: Blog
JBA are supporting the implementation of a scheme that is looking to maximise River and Floodplain Connectivity, also known as Stage 0 restoration, within the National Trust Holnicote Estate in West Somerset. Working with the National Trust, Wolf Water Resources, Exeter University, and the Environment Agency, the project aims to return a section of the River Aller to a more natural multi-threaded course through its floodplain to help mitigate the impact of climate change, reduce flood risk, improve water quality and to make more space for nature. It is one of the first restoration schemes of its kind in the UK allowing more natural processes to develop over time which has been inspired by similar successful restoration projects in the American Northwest, including Five Mile Bell in Oregon (https://www.siuslaw.org/current-projects/).
The experiences in the State of Oregon demonstrate that when river and floodplain systems are restored to ‘Stage 0’, natural processes can recover, and various habitats are created that then attract multiple wildlife species. In many cases this recovery leads to a slower flowing river system with multiple, smaller channels, pools, riffles and valuable wetlands being developed that can support a much richer diversity of flora and fauna.
Holnicote Estate – Initial River and floodplain connectivity restoration scheme on a small watercourse
Two existing straight channels were in-filled, and all the water flow allowed to spread widely into multiple flow pathways across a much rougher undulating field surface which was further broken up by the addition of woody material (tree trunks, branches, etc.) orientated across the land slope.
One of the first restoration schemes of its kind in the UK
JBA and Wolf Water Resources will be using their specialist geomorphological, natural flood management/working with natural processes and environmental engineering knowledge to develop a full river and floodplain connectivity scheme on the main River Aller through on-site surveys/assessments and GIS analysis. Detailed hydraulic modelling will also be undertaken to inform the design and to quantify how it will reduce flood risk to communities at risk downstream, whilst producing much wider benefits for the environment and society. The National Trust will be engaging with all the relevant regulatory authorities with respect acquiring all the necessary permissions, consents and approvals for this type of scheme.
This work expands on the previous natural flood management projects that we have undertaken for the National Trust on the Holnicote Estate, including the Holnicote Multi-Objective Flood Management Demonstration Project (2009-2015). This earlier study was one of three studies commissioned by Defra in response to the recommendations were published in the Pitt Review of the summer 2007 floods. It generated a considerable body of evidence to demonstrate how integrated catchment management change, working with natural processes, implementing a range of NFM measures and partnership working can all contribute to reducing local flood risk and deliver multiple benefits.
Natural Flood Management Experience
We have extensive experience in natural flood management (NFM)and are one of the leading consultancies in this field in the UK. We are also making significant technical contributions to two of the major NERC funded NFM Research Projects (Q-NFM and LANDWISE-NFM). The scope of this research has been co-designed with project partners: NERC, Defra, the Environment Agency, Scottish Environment Protection Agency, the Welsh Government and Natural Resources Wales to improve our understanding of the effectiveness of different NFM measures across a range of flood risk scenarios, thereby addressing some of the known knowledge gaps.
Read the full research report here https://research.reading.ac.uk/nerc-nfm/
Want to know more?
We provide numerous services across the full NFM spectrum of topics, including:
- NFM Research and Assessments
- NFM Potential Mapping
- NFM Hydraulic Modelling
- NFM Surveys
- NFM Engagement
- NFM Training
- NFM Barriers and Enablers
- River Restoration
- Geomorphological Assessment
- Ecological Assessments
- Fisheries Science
- Fish Pass Design
- Habitat Surveys
- Hydraulic Habitat Modelling
- Water Framework Directive (WFD) Assessments
- River Restoration Feasibility and Design Studies
We have over 10 years’ experience in natural flood management and led the consortium that worked with the Environment Agency to publish the Working with Natural Processes Evidence Base in 2017.
If you would like more information, please contact our NFM lead, Steve Rose.
You can also find out more on our Natural Flood Management webpages.