"A Clear Future for our River"


The Bristol Avon Waterblitz returns!

Bristol Avon Rivers Trust (BART) is excited to announce the 2018 Bristol Avon WaterBlitz; a campaign to collect as many water quality samples as possible in a week from across the Bristol Avon Catchment, between Sat 23rd– and Fri 29th June 2018.

Our rivers are the central artery of the catchment with a fascinating history, beautiful scenery and stunning wildlife. Water quality in rivers across the country has been a key conservation issue over the last few decades and efforts to monitor and clean up our rivers mean that otters, kingfishers and water voles are all making comebacks on the banks of the Avon and its tributaries. However, water quality is still a massive challenge and BART need your help to fill the gaps in our knowledge.

Thanks to funding from the Bristol Avon Catchment Partnership, BART is working in partnership with FreshWater Watch, a global programme developed by the environmental NGO, Earthwatch. This charity aims to connect people with science and nature, engaging people in citizen science to build up a wealth of research data collected by volunteers from all over the world.

BART is asking individuals and community groups to take part in the WaterBlitz this year and help to collect as many water quality samples as possible (last year we had 376 people involved!) within the Bristol Avon catchment, including Bristol, Bath, South Gloucestershire, Wiltshire and North East Somerset.

The Bristol Avon Catchment

Using the free and simple to use water testing kit, volunteers can sample their chosen river or stream in the Bristol Avon catchment and upload the results to the FreshWater Watch website to compare the water quality level to other sites on an interactive results map.

To register and take part this year please follow the link below to sign up and you will then receive a free water quality sampling pack in the post.  Sampling kits are limited so please register by Friday 15th to ensure you can participate: https://freshwaterwatch.thewaterhub.org/group/bristol-avon-blitz

If you have any questions or queries about the 2018 Bristol Avon WaterBlitz please contact Alec at alec@bristolavonriverstrust.org

Thank you for helping to improve the water environment in the Bristol Avon for future generations!

River Marden 2018 fisheries improvements

Project background

In 2017, Bristol Avon Rivers Trust (BART) applied to the Environment Agency’s ‘Fisheries Improvement Fund’ following a walkover survey of the entire length of the river and several small improvement projects over recent years.

The River Marden rises in Calstone Wellington, Wiltshire and runs through the town of Calne, then
through pasture and villages before joining the Bristol Avon to the north east of Chippenham. Water
Framework Directive (WFD) status along the river varies between Good and Moderate (in the lower
catchment). The river has a number of issues along its length that are resulting in the degradation of
both water quality and fisheries habitat. These include river impoundment and fish passage
restrictions by weirs, as well as the historic straightening of large sections of river.

The objective of this project was to contribute to addressing some the main issues affecting the river.


2017-2018 Improvement works

Weir fish passage feasibility studies

The River Marden is predominantly a coarse fishery (notably roach, dace, chub, perch, pike, bream,
barbel, bleak and gudgeon) though wild brown trout are found in large numbers throughout the
river. There are a number of obstructions along the river which impact on the movement of fish and
also the quality of habitat upstream of the obstruction i.e. the creation of a silted bed substrate and
impounded flow conditions.

BART identified three weirs; Moses Weir, Stanley Weir and an unnamed bedrock weir where fish passage and, if feasible, upstream riverine habitat improvements following the weir removals, would gain significant benefits for the river. Hydro-Morph Ltd was commissioned by BART to undertake an initial site visit and pre-feasibility investigation of possible options for improving fish passage and upstream habitat at each structure. These reports have been completed and provided to the Environment Agency Fisheries and Biodiversity team.


In-stream habitat improvement works

This element of the project worked on an overshaded and straightened section of the river
downstream of Chilvester Hill, Calne. Low cost improvements were delivered here including coppicing to re-instate a 60:40 ratio of shade to light. In-stream wooden flow deflectors were
constructed from bankside materials to help re-meander the river within it’s straightened banks.

In total BART constructed 11 structures, which will have a variety of benefits including increased
flow diversity, cleaner spawning gravels and providing enhanced fish cover for fry and adult fish. We
are looking forward to seeing how these structures develop as similar structures we have built on
the river in Calne have been very well received and had an almost immediate impact on the river
and the sport provided. The Marden is a relatively spatey river so we anticipate that the structures
will be well hidden by silt accumulation in a year and will form part of a newly meandering bankside
within 2-3 years. We will continue to monitor the progress of these structures as this occurs.


Figure 1. A ‘pinch point’ created with a wooden berm which will encourage flows to scour the gravels, flushing out silt and improving fish spawning potential.


Figure 2. Alternate berms constructed to re-form a meander within the banks of this straightened section.


Boulder weir removal

BART’s survey work on the Marden identified two boulder weirs immediately above the confluence
of the river with the Bristol Avon at Chippenham. The weirs presented a barrier for smaller, weak
swimming species as they were only passable in high flow conditions. The lower sections of the
Marden have important spawning gravels and increasing access to these will help gravel spawning
species increase recruitment. The lower Marden also acts as an important refuge when the main
river is in spate. The weirs were also contributing to silt build up in the stretch of river above them
which was having an adverse effect on fish spawning as the riverbed gravels had become smothered
in sediment.

The two boulder weirs were removed as part of this project and the once uniform deeper section of
river with slow flows, is now shallower with riffles, exposed gravel bars and less silt deposition
creating new potential spawning grounds. BART will now leave the stretch to adjust to the new
conditions for a year before reassessing whether there is a need for any follow up habitat work.


Figure 3. Before and after – removal of one of the boulder weirs.

Thanks to all of our fantastic volunteers for their help with this project, to the landowner, land agent and tenant farmer for their help and enthusiasm and of course to the Environment Agency for funding these works. A huge thank you also to Wroughton Angling Club and Calne Angling Club, without whom this project would not be possible. We are looking forward to continuing to improve the Marden!

Can you help us to improve the River Marden in Calne, Wiltshire?

We are looking for volunteers to take part in a river restoration project which is taking place from 26th February – 2nd March and on the 5th and 7th March 2018. Work days will be from 10am – 3.30pm but you are welcome to come for as many days and for as long as you like.

The work will involve working on the bank and in the river helping to install woody habitat to improve flow, depth and habitat diversity for wildlife. Activities will include hand sawing, post banging and dragging branches. All equipment, including waders, tools and gloves, will be provided but you will need warm and waterproof clothing, food and drink and will need to make your own way to the site.

Volunteering with us is a great way to get outside, meet other like-minded people and do something positive for our local rivers!

For further information and to sign up, please email Harriet on harriet@bristolavonriverstrust.org

The Magnificent Marden Project continues to grow

BART have been working to improve the River Marden in Calne for a number of years now. To date, this has included in-stream habitat works, local engagement with presentations, education sessions (such as river dipping with the local Scouts Group) and Riverfly monitoring training.

Calne scouts out river dipping in the River Marden in 2016.

Whilst all of these activities have been occurring, we have been working in the background to get together a river Catchment plan for the River Marden by doing a series of walkover surveys and landowner/leaseholder meetings along the length of the river. As a result, we have a number of improvement areas that we will be searching for funding for over the coming years.

We are pleased to announce that a number of these improvement areas will be ticked off as we have secured funding from the Environment Agency’s Fisheries Improvement Fund, which comes from the sales of rod licences and goes directly into capital improvements in our rivers of angling interest – another great reason to make sure you have a rod licence before you go out fishing, the other one being bailiffs!

This project (which will hopefully be Phase 1 of several) will include the following actions:

  • The removal of two boulder weirs which are impounding the river, resulting in reduced flow diversity and silt accumulation on substrates.
  • Coppicing of a large section of overshaded, canopied river.
  • In-stream woody habitat works to increase flow, habitat and depth diversity in a straightened section of the river.
  • Initial fish passage investigations for two barriers to migration.

One of the impounding weirs

We will keep you updated as this project continues!

We would also like to thank the individuals who have recently reported local concerns regarding river health to us as well as the community groups who have recently met with us to discuss sourcing funds for future improvement options.

If you have any questions or would like to help out to improve the Magnificent Marden with either volunteer time or sourcing funding, please get in touch with BART Project Manager on harriet@bristolavonriverstrust.org

Thank you volunteers!

In 2017 our wonderful volunteers contributed 4226.5 hours to BART to help restore and protect our rivers!

We would like to say a huge thank you to every single one of our volunteers, we couldn’t achieve half as much without your support. In total 826 people from across the Bristol Avon catchment got involved with our projects ranging from research, practical river habitat improvements and education.

If you would like to volunteer with us in the future please keep an eye on our website volunteering page, where you’ll find a summary of opportunities and our events calendar (www.bristolavonriverstrust.org/who-we-are/rivers_trust_supporters/).  On this page you’ll also find information on volunteering as a BART Beacon, where you can sign up to be the eyes and ears on a section of river local to you. We are building a network of beacons across our catchment so that we can keep an eye on as many rivers as possible!

Once again a huge thank you and well done to everyone who volunteered with us this year, we look forward to seeing you again in 2018!