Why Re-Wiggle Rivers?

When you look at an old map or aerial photo, you’ll often see rivers winding gracefully through the landscape, forming a series of bends and loops. These natural curves – called meanders – are part of how rivers shape themselves over time. But in many places, especially during the last century, rivers were straightened or ‘canalised’ by people. They cut off their bends, turned their paths into rigid channels, and confined them between banks. The idea was to control flooding, drain land for farming, and move water quickly.

At the time, it seemed efficient, but over the years we’ve learned that straightening rivers can have serious consequences. A straight river flows faster, which can lead to more erosion, more downstream flooding, and less opportunity for water to soak into the ground. It often loses the variety that wildlife depends on and becomes disconnected from its natural floodplain. Instead of a living, breathing system, it can turn into a lifeless drainage ditch.

That’s why, across the UK and beyond, organisations are working to un-do some of that work. We’re re-wiggling rivers.

So why are we doing it?

1. Better for Wildlife

Natural rivers are full of variety – slow sections and fast flows, deep pools and shallow riffles. This variety creates perfect homes for insects, fish, birds, and mammals. A straightened river often becomes uniform and lifeless, like a conveyor belt of water. By adding meanders and restoring natural features like gravel beds, fallen trees, and wet margins, we bring back the conditions wildlife needs to thrive.

Species like the Atlantic salmon, kingfisher, water vole, and freshwater pearl mussel all benefit from a healthy, diverse river.

2. Slowing the Flow

Straightened rivers rush water downstream much faster. That can increase the risk of flooding in villages and towns further along the catchment. By adding meanders, we slow the water down. It takes a longer path, spreads out into floodplains, and soaks into the ground. Re-wiggling rivers helps us work with natural processes, not against them, making communities more resilient to flooding.

3. Cleaner Water

When water rushes through a straightened channel, there’s less time for it to settle, filter through soils, or interact with plants. That means pollutants like nutrients and fine sediments are swept straight into lakes and estuaries, where they can cause problems like algal blooms. Re-meandered rivers give water a chance to pause and be naturally cleaned. Wetlands and river margins act like nature’s kidneys, filtering out the muck.

4. Restoring the Landscape’s Memory

Many rewiggling projects use old maps and local knowledge to find the river’s original path. In a way, we’re letting the landscape remember what it once was. Sometimes we uncover forgotten channels still visible in the land, like ghost rivers waiting to flow again. By restoring these ancient paths, we reconnect the river with its floodplain, history, and story.

5. For People

Rewiggled rivers are often more beautiful and more accessible. Meanders create peaceful places to walk, paddle, birdwatch or just enjoy nature. Volunteers are often central to these projects – planting trees, stabilising banks, monitoring wildlife, or helping with community engagement. It’s a chance to get involved and see positive change in action.

An Example: Penhesgyn’s Centre Rewiggle

Using natural materials to diversify flow and improve habitat

Early stages of the river starting to form a natural path across the land

Last year, as part of our Swimways project, we brought some of this thinking to life at Penhesgyn, where we rewiggled a straightened stream that flows into the Afon Braint. Working in partnership with the Wildlandfill project, we created a more natural meandering course through what had once been landfill, now being transformed into a thriving mosaic of wetland and woodland habitats.

Nature Knows Best

Rewiggling rivers isn’t about recreating the past perfectly. It’s about giving rivers room to move and function naturally again. As the climate changes and pressures on our water systems grow, these kinds of restoration projects are more important than ever.