Restoring Chalk Stream Habitat in Alresford

Restoring Chalk Stream Habitat in Alresford

A popular walking route and stretch of chalk stream have both been restored, as the Watercress and Winterbournes partners head to Alresford.

Wandering through the centre of Alresford, you're never far from the chalk stream that lends the historic town its name. The River Arle weaves between buildings and winds through corridors of lush greenery, accompanied at various points by popular public walking trails.

As one of around 200 worldwide, this chalk stream is immensely precious. It is even home to our native white-clawed crayfish; an endangered species now only found in a last few strongholds. Such special qualities make it much loved by the local community, but also at risk from a gradually mounting threat.

Just upstream of the Eel House, a stretch of footpath had fallen into disrepair. This route was enjoyed by residents and visitors alike, but was becoming impassable even with regular repairs. Happily, a more permanent solution was proposed through the Watercress and Winterbournes Landscape Partnership Scheme.

Washing away

The causes for the footpath's decline were numerous and interlinked. High footfall caused the surface to wear down, and also prevented the growth of the vegetation that would normally secure the soil. The plants that did pop up were stunted by the heavy shade cast by nearby trees. The bank side of the path was further scoured by the stream whenever the water level was high.

These factors combined to cause gradual but significant bank erosion. This was especially noticeable on the footpath, which developed narrow sections and large dips that often filled with rain. This made the route increasingly tricky to navigate, and mostly inaccessible for those with low mobility. But there was another, less visible casualty: the health of the adjacent chalk stream.

As the bank and path crumbled, sediment was being released into the water. It settled on the gravelly bed, preventing fish from breeding and leaving invertebrates without a home. As the sediment built up the stream grew shallower, making it sluggish, warm, and more likely to overflow. Vegetation dwindled, compounding the erosion and reducing the available shelter for water voles.

Shoring up

Scheme partner Wessex Rivers Trust began tackling these issues in October 2021. The footpath was re-surfaced, and widened enough to allow passing pushchairs. Replacement bank supports were added and reinforced by buffers of woody debris. A silt curtain - newly purchased to avoid exposing the white-clawed crayfish to any contamination - kept the stream clear during the disturbance.

These improvements will be invaluable for securing the bank, but its long-term stability depends on the return of sufficient vegetation. Plant growth will lock the soil in place and shield it from the flowing water, in addition to providing important wildlife habitat. To encourage this, Wessex Rivers Trust thinned the trees to let in more sunlight and added native plants to bolster the natural re-growth.

Vegetation is vulnerable to trampling, particularly while getting established, so the bank is now protected by a low fence with an access area where dogs can enjoy a dip. In November, our brilliant volunteers returned to 'hinge' trees into the channel - partially cut through, the trees still grow but can be laid down to form 'pinch points' that hasten the flow and help sweep excess sediment away.

Moving forwards

As of spring 2022, signs of success have started to appear. The bank is growing greener as new plants populate the area. The gravelly bed near the pinch points is largely free from sediment. The footpath once again offers an enjoyable walking route. The full impact will take time to manifest, but we look forward to assisting the community with their ongoing care of the stream.

These restorations were made in memory of local residents Mike and Bridget Newitt, whose bequest of £10,000 enabled us to make more extensive repairs. Their generosity, and its legacy, has been commemorated by an information board next to the Eel House. We are also hugely grateful to Alresford Rotary Club, who facilitated this funding and supported us throughout the restoration process.

Cherishing our chalk streams

If you love our local chalk streams, then why not check out the Watercress and Winterbournes Landscape Partnership Scheme? With more than 20 projects to choose from, you can try everything from nature crafts to species surveys. We've welcomed a wonderful community that spans all seven headwaters of the Rivers Test and Itchen, and would love to hear from you.

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