The restoration of a straightened river included re-connecting the river to its surrounding floodplain and creating storage ponds and small wetlands. These measures aimed to improve natural flood management of the catchment while also restoring biodiversity.
Eddleston Water was a straightened river that risked flooding 500 properties downstream. Therefore, the Scottish Tweed Forum embarked on an assessment of the natural flood management potential associated with restoring Eddleston Water. Working with local landowners, they managed to plant over 200 hectares of native trees, create cross-slope hedgerows, and install 116 log barriers on high tributaries to create small wetlands. Furthermore, 28 flood storage ponds were created, three kilometres of the main river were re-meandered, and several embankments were removed reconnecting the river with its surrounding floodplain.
Overview of context and outcomes:
Straightened rivers, as opposed to natural meandering rivers, are associated with negative environmental impacts caused by faster flows, the diversion of rivers from natural recharge points, and the disruption of natural wildlife habitats. The combined interventions implemented are intended to reduce flood risk in the river catchment as well as restore the natural ecosystem of the river.
Benefits from carbon storage as a result of the river restoration are estimated to be worth £GBP 717 thousand (net present value) over 100 years.
Analysis reported that flood peaks were reduced by 30% and delayed by over four hours, avoiding an estimated £GBP 950,000 of flood damages and protecting 500 properties downstream.
It is reported that gravel banks and pools formed by the restoration of the river have improved habitat quality which has led to an increase in spawning salmon and other fish. Ecological status of the river has been improved from ‘bad’ to ‘moderate’ under the EU Water Framework Directive Assessment.
The project has worked with landowners, farmers and foresters to ensure continued profitability for local industries while also supplying reduced flood risks and potential for economic damages to surrounding areas.
The Tweed Forum, which works on the Tweed water catchment, organized a partnership between government bodies, NGOs, local landowners, and regional communities to address the flooding risk presented by the Eddleston Water.
The project is financed by the Scottish Government and the Scottish Environment Protection Agency (SEPA).
A highly comprehensive monitoring program has been implemented with hydrometric network monitoring, groundwater monitoring, water quality measurements as well as ecological and geomorphological surveys.
No information yet available on tradeoffs and limitations.