Many of our rivers and streams have been modified gradually throughout the centuries.

Most notable are the reservoirs, which account for most of the ‘heavily modified’ condition assessment carried out by the Environment Agency. But other, less noticeable changes such as straightening, disconnecting flood plains and gravel flows, and loss of riverside trees and other habitats have also occurred that affect how good our rivers and streams are for wildlife. Mines, soughs, drains and culverts also affect the way water flows through the landscape.

Straightened watercourses, or those with heavy outflows such as drains, often flow too quickly for fish species such as trout and salmon to spawn, and are murkier as more sediment is eroded from the banks. Adding in bends increases the size of available aquatic habitats as well as slowing the flow, which can reduce flood-risk (opens new window) further downstream.

For nature

• Restoring a waterway’s natural course adds length to riparian habitats at different scales that can be used by many species.
• Meanders, gravel banks, deep pools and turbulent riffles create many diverse habitats that different species can use.
• Riffles can also help to draw oxygen into the water.
• Slower moving, re-wiggled, rivers move less sediment, exposing gravel beds and other areas for fish to spawn.
• Barrier free waterways allow fish to move freely, increasing the areas in which they can migrate to and breed in.
• As well as creating more, larger habitats (opens new window), restored waterways (and their surrounding habitats) provide opportunities for "green and blue wildlife corridors" (opens new window), connecting different habitats from the uplands to the sea, and often running through urban areas, connecting cities to nature.

What else can natural courses deliver?

• Reintroducing meanders increases water holding capacity and slows the flow - natural flood management that reduces flood risk downstream and potentially the need for costly hard infrastructure.
• Watercourses with less infrastructure need less, often expensive, management, for example less drainage maintenance or time unblocking culverts.
• Health and wellbeing benefits of linking towns and cities to the wider countryside, including opportunities to add footpaths and cycle lanes (opens new window) along waterways.
• Cleaner, more "natural looking", rivers with increased biodiversity will enhance the experience of visitors to the area, connecting them more deeply to nature and encouraging more responsible behaviour than murkier, less diverse waterways.

In practice

• Rivers can be re-wiggled using earth moving machinery (opens new window) to restore their natural course.
• Re-connecting waterways to floodplains and wet meadows (opens new window).
• Removing artificial sides and river banks to create more habitats around rivers and make access in and out of them easier for a range of different species.
• Remove artificial drains to create a more natural flow of water into rivers and streams.
• Create more and link watercourses to wet woodlands.
• Removes barriers to the natural flow of gravel/shingle.
• Removing culverts to "daylight (opens new window)" watercourses and increase their water capacity during floods.
• Shorten and replicate the natural turbulence and environment of the surrounding river in culverts that cannot be removed.
• Make room for future natural river course changes.
• Historic research can identify features such as former water meadows and old river channels.
• Conduct hydrological surveys and modelling (opens new window) more regularly to monitor watercourses and predict flooding patterns (opens new window).
• Follow Environment Agency guidance (opens new window) when installing, maintaining or removing other infrastructure in or around waterways.

CASE STUDY Removing culverts at Hillsdale Farm