PROJECT

Acacia Hall River Restoration

A 600m stretch of the River Darent chalk stream has been turned from a backwater into a flowing, natural river as it passes through Central Park in Dartford.

We have worked in partnership with Dartford Borough Council, the Environment Agency and CBEC to design and deliver a showcase restoration project that reintroduces chalk stream river form and function on the Darent.

River Darent after restoration River Darent after restoration © South East Rivers Trust
River Darent after restoration River Darent after restoration © South East Rivers Trust

  • Project started in

    2018

  • metres of chalk stream restored

    600

  • Completed in

    2021

Problems of man-made modifications

The Darent suffers from a legacy of modification.  Remnants from former water mills, over-abstraction, polluted outfalls, flood risk prevention measures and weirs all fragmented this precious chalk stream habitat. These changed the river from a continuous, free-running ecosystem into semi-isolated or stretches of standing or slowly moving water. This physical impact completely alters chalk stream ecology, impeding the movement of many aquatic species and affecting water quality.

The part of the Darent that runs through Central Park was in a similar state of neglect, resembling a forgotten backwater.

Acacia weir that has been removed © South East Rivers Trust

Removing the weir and naturalisation

In 2019, the South East Rivers Trust began working with Dartford Borough Council and the Environment Agency on the Acacia Hall/Central Park Restoration Project.

This has brought the Darent back into the heart of Central Park by removing the Acacia Hall weir and using flood risk neutral, nature-based methods and materials to reintroduce chalk stream river habitats and function.

The Central Park section of the Darent is now flowing again, allowing the public to spend time by a natural chalk stream with improved water quality and benefits to wildlife such as salmon, brown trout, European eel and invertebrates.

Our river restoration project has reintroduced natural features to the river, to create the type of variation in channel width and depth found in less disturbed river systems.

The River Darent in Central Park Dartford was choked with vegetation © South East Rivers Trust

Improving habitats

These improvements have begun to kick-start more natural, variable flow patterns – creating a greater variety of habitats that attract and support wildlife. Greater habitat diversity supports more resilient wildlife communities.

The restoration has used materials that naturally occur in river ecosystems, such as large woody material, gravel and silt.  Trees were selected and felled from Central Park for re-use in the restoration project.

Many of the selected trees were damaged, hazardous to the public or were self-seeded sycamore. Sycamore is a fast-growing non-native tree species that out-competes many native tree and shrub species, and blocks out the sunlight to the river.  By opening up areas at selected sites in Central Park and Acacia Hall, the restoration project created a mosaic of sunny and shaded spots for river habitats.

Completion of the Acacia Hall restoration project © South East Rivers Trust

Joy at post-lockdown grand opening

To enable the work to take place safely in the channel, the water level was lowered and flow was diverted down the flood relief channel to the east of Central Park. This minimised any harm to wildlife during restoration.

After three years of hard work, the site is a very different one to which the South East Rivers Trust came in 2019. A 600 m stretch of river, cut off, over-widened, choked with silt and vegetation and heavily shaded with sycamores, has been restored.

On channel opening day – written about in a blog –  at the end of March 2021, clear water glided over clean gravel down the restored reach of bubbling chalk stream, with fish rescued from the western channel. Another blog from June 2020 features progress along the way.

 

Fish released into the Central Park Dartford river at the end of the Acacia Hall project © South East Rivers Trust

Thanks to our supporters

Environment Agency
Dartford Borough Council
Veolia

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