Glorious gravel boosts the Blackwater

Glorious gravel boosts the Blackwater

Assistant Project Officer Luke Beckett reports on a week-long series of events with volunteers in mid-March, putting gravel into a stretch of a River Loddon tributary to improve conditions for river wildlife.

River Blackwater gravel installation
Some of the gravel was transported by dinghy © South East Rivers Trust

Anglers and conservation enthusiasts were among more than a dozen volunteers who joined us for the exhausting but rewarding task of installing more than 19 tonnes of gravel into the River Blackwater. In joining us earlier this month, they added a vital resource to help nature thrive into a 200 metre stretch of the river in Aldershot.

The newly seeded gravel, which is the final part of our Blackwater Valley river restoration work, will provide improved habitat for macroinvertebrates such as beetles, dragonflies and mayflies. It will also help aquatic plants thrive, as well as increasing spawning habitat for fish.

The River Blackwater at Ivy Road has historically suffered from bank and riverbed modifications. This section of the River Loddon catchment has been widened and deepened, leaving a uniform channel with little variation in water depth.

The channel has lacked flow energy and habitat diversity and subsequently, silt and fine sediments had built up, smothering the riverbed. Moreover, the site is just downstream of the Aldershot sewage treatment plant, which regularly discharges sewage effluent into the channel.

Since 2021, the South East Rivers Trust has worked with support from the Environment Agency and the Blackwater Valley Countryside Partnership, plus local volunteers, to improve this stretch of river.

Installing gravel at River Blackwater
Will the pile of gravel ever go down? © South East Rivers Trust

The in-channel deflectors and berms previously installed have helped to narrow the channel and increase water flow velocity, as well as habitat complexity. The increased velocity has already cleared much of the fine sediments and silt.

The newly-seeded land-based gravel will move around with the natural ebb and flow of the river, settling to form natural river features, such as bars, riffles and deeper pools.

This clean gravel and variety of river habitats is essential for river life: the River Blackwater supports a number of fish species – such as chubb, roach, perch, dace, gudgeon and rudd – all of which should benefit from this improved spawning habitat.

Gravel seeding is not the most glamorous of tasks. This site delivery was no different and was made difficult by the lack of access routes.

 

Raking gravel into the River Blackwater
Raking gravel into the River Blackwater © South East Rivers Trust

Large vehicle access to the river was not possible, which meant a lot of moving wheelbarrows loaded with heavy gravel from our drop off location to the channel itself.

The distance was at least 75 metres and up to 200 metres to push the gravel to the correct places, making this tough physical work. Wader wearing volunteers also had to rake the gravel once in the riverbed, sometimes having taken it to an appropriate location in a dinghy.

It was slow going at times, leaving us questioning whether the gravel pile was even going down! But, after four days, including a lot of rain, not enough sunshine and many teas, coffees and biscuits, the gravel pile was finally gone and the last wheelbarrow and boat load were emptied.

The team took a moment to look over their hard work from Ivy Bridge, where a few curious fish were already checking out the new riverbed, before the heavens opened once again!

This brings our river restoration work at Ivy Road Recreational Ground to a close, but we look forward to returning over the coming months and years to see how the channel responds.

Gravel and brash berms
The final scene: Gravel on the left is complimented by previously installed brash berms on the right © South East Rivers Trust

Liven up the Loddon in Rivers Week

Volunteers sought for gravel seeding and planting the ‘Loddon Lily’

Organisers of the annual Loddon Rivers Week are appealing for dozens of volunteers to don wellies and waders and help meet ambitious targets to put 75 tonnes of gravel into riverbeds.

‘Gravel seeding’ events, which will improve spawning habitats for fish and invertebrates, are among seven public volunteering activities during the annual focus week on the Loddon, co-ordinated by the South East Rivers Trust since 2017.

Another key activity of the week, running from 18th-24th September, will be a chance to plant one hundred Loddon Lily bulbs, re-establishing a rare species.

The Loddon Lily
Replanting the Loddon Lily we be a big focus of the week – Summer Snowdrop, by Elizaveta Mitenkova/Pexels

Adopted by many as the Emblem of the Loddon, where it was first found and categorised, this plant is also known as the Summer Snowflake. It looks similar to a snowdrop, but has more open flowers of drooping, white six-petalled bells. Growing next to rivers in April and May, the Loddon Lily produces seeds in July, which disperse along water courses.

The River Loddon, which rises in Basingstoke and stretches across Hampshire, Surrey and Berkshire before reaching the Thames at Wargrave, has plenty of special characteristics. Its upper reaches – where many of the Loddon Rivers Week events will take place – are globally rare chalk stream habitats, hugely valuable for biodiversity and home to brown trout, water voles and otters.

Twelve organisations, from conservation groups to local authorities, are ready to welcome volunteers, or simply people who are interested in learning more from experts in their fields.

Lou Sykes, Catchment Officer at the South East Rivers Trust, said: “Like most rivers in England, the Loddon faces many challenges such as pollution, invasive species and poor habitat and water quality. Loddon Rivers Week gives local people a real chance to do something about this by getting involved in conservation.

Bassetts Mead gravel seeding
Gravel was added to the river at Bassetts Mead in Loddon Rivers Week 2022

“This work is vital to improving rivers and helping a wide range of wildlife thrive around it. Last year, volunteers were thrilled to see instant results of fish investigating the 30 tonnes of newly laid gravels on one riverbed and this year we have several opportunities to do this vital work in different places.

“Improving rivers and their surroundings makes them wonderful places not only for nature but also to visit. So, we’re particularly excited about boosting numbers of the beautiful Loddon Lily at our planting event, which will be huge fun for all the family.”

Loddon Rivers Week is supported by the Environment Agency and, for the first time, Network Rail.

The public will need to sign up in advance for activities:

Monday 18th September and Tuesday 19th September: Get stuck in to gravel seeding to create spawning ground for fish at Greywell Flyfishers Club, Hook, on the River Whitewater, 9am to 5pm.

Wednesday 20th September: Don waders for restoration work at Ivy Park Rec on the River Blackwater, Aldershot with the South East Rivers Trust and the Blackwater Valley Countryside Partnership, 10am to 3pm.

Wednesday 20th September: Come and install woody deflectors in the River Whitewater, creating some fantastic flow diversity in the watercourse at Greywell Flyfishers Club, 9am to 5pm.

Wednesday 20th September: Plant the Loddon Lily, re-establishing this rare species at Wokingham’s riverside parks.

Thursday 21st September: Join in gravel seeding at Bassetts Mead on the River Whitewater with the Hampshire & Isle of Wight Wildlife Trust, Network Rail and Hook Parish Council, 9am to 3pm.

Saturday 23rd September: The Chineham Conservation Group wants your help clearing vegetation to provide some much-needed light to the Pettys Brook. Tasks also involve a litter pick.

To book a place on any of the activities, visit our events page.