Remeandering straightened channels and reconnecting them to their floodplains slows the flow and improves wildlife habitat.
Most of Scotland’s waterways have been artificially modified by people over centuries, making them straighter, deeper and faster. This drains land efficiently, but it also destroys wildlife habitat and concentrates the flow of water downstream towards villages, towns and cities.
As climate change increases the risk of heavy rainfall, restoring rivers to a more natural state can slow the flow, revitalise lost wetland habitats, and bring benefits for both people and wildlife.
How does it work?
There are two ways to remeander a river.
- The fastest way is to use machinery to remove artificial embankments and reprofile the channel, carving out a new, wiggly, less steep-sided channel.
- Anchoring large trees in the channel and building leaky dams slows down the water and forces it to move sideways, encouraging horizontal erosion. It takes longer for the river to revert to its natural form, but is cheaper and less intrusive than using machinery.
Before restoration
This steam has been straightened to improve drainage, creating a simplified, deeply-incised channel.
- Artificial embankments, like stone walls, keep the channel straight and prevent meandering. This causes the channel to erode vertically downwards, become deeply incised and disconnected from its floodplain.
- Additional drainage ditches channel water efficiently from the land into the river, exacerbating flooding downstream.
- The simple channel provides poor wildlife habitat, with fewer pools to shelter in.
After restoration
Remeandering helps the river to return to its natural form, slowing the flow and providing wildlife habitat.
- The remeandered channel is longer and creates more friction, slowing the movement of water downstream and helping to mitigate flooding.
- Remeandering creates a variety of complex habitats, with braided channels, beaches, pools and islands. This enables lots of different species to thrive.
- The river has been reconnected to its floodplain so that during heavy rainfall, excess water can be absorbed by the land rather than rushing downstream where it may flood homes and businesses.
CASE STUDY: Rewiggling the Beltie Burn in Aberdeenshire resulted in the rapid return of wildlife, including lampreys and wading birds. The river’s capacity has increased and water can spread across the floodplain when it needs to, easing the flood risk for downstream towns and villages.