Contact for More Information: KierenA@essexwt.org.uk
Billericay and District Angling Club run a site known as Straits Mill. This former gravel extraction site was converted to a fishing club and provides high-quality riparian habitat adjacent to the River Blackwater and the Braintree Council owned Bocking Blackwater Local Nature Reserve.
The purpose of the project at Straits Mill was to renovate and rehabilitate an old flood attenuation pond adjacent to the River Blackwater to provide higher quality riparian habitat. Initially constructed in the 1980s, this feature had over time become increasingly overgrown and overshaded with a combination of Alder, bramble and nettle. It had more importantly completely separated from the river, becoming increasingly stagnated with both the mud and water quality almost lifeless.
Given the current status of the pond, and the complete lack of invertebrate interest, it was decided to completely reset the clock on this pond and remove the overshading trees, reconnect the original pipe and open up the return channel to the river for the benefit of fish, invertebrates and flora. It will also serve to store and attenuate flood water by being hydrologically linked to the river.
The work on the pond was undertaken in winter 2015. Once the trees were in full leaf, little or no sunlight would be able to reach the surface of the pond. The task in October 2016 was to remove the overshading trees to aid both access for machinery and to help increase the amount of light reaching the surface of the renovated pond. Once the trees were removed they were chipped up to reduce arisings. The water colour was a dark black which suggests de-oxygenated and stagnant water.
With the trees out the way, the excavator was able to access the pond and begin desilting the base and extending the area of the pond. Once the desilting was complete, the next task was to reprofile the sides of the pond and place the coir roll. The way water worked around the site was also changed, with the pipe lowered to ensure that water was always present in the pond.
The final product has an increase in water as it has a much more open aspect, with the overshading completely removed. As it settles down we expect to see some great results from this project, not only ecologically but in its ability to hold and attenuate floodwater.
Thanks and acknowledgements must go to Billericay District Angling Club and its members, also the Environment Agency for supplying the funding.
Subscribe to the Essex Rivers Hub newsletter to hear about our latest work and project updates from the catchment partnership.
Website designed and developed by Studio Seventeen Ltd.
The topics below represent the pressures that many waterbodies in the Combined Essex catchment face. They have been divided into six main categories, but it is quite often that these categories can overlap as pressures relate to each other.
Diffuse pollution occurs as water moves across the land or through the ground and picks pollutants. These pollutants can come from a variety of places, including urban and field run off. The pollutants that enter the river can range from sediment to toxins to excess nutrients, meaning that diffuse pollution can cause a whole range of different issues. The variety in these pressure groups means that it is something that can be quite difficult to tackle. It requires groups of people, business and stakeholders to work together in order to solve this problem.
Fish should be able to travel up and down a river freely, allowing them to move and breed in the most suitable habitats for them. It is important that fish populations do not become isolated, as this makes them more susceptible to disease and puts pressure on their survival. Unfortunately, there are often many barriers along rivers that prevent fish from being able to migrate up and down stream. Where barriers have been identified, they will be seen as a ‘pressure’ on a waterbody. Thankfully, there are many solutions now that can be put in place to aid fish passage, even over large barriers.
The flow in a river can vary greatly throughout the year as rainfall and run off can have an effect. This is a natural process. It is when flow is impacted by non-natural processes that it can cause problems. Sometimes, water can be intercepted or removed from a system; this will reduce the flow, therefore changing the habitat conditions. Some species are happy in high energy rivers. This means that when flow is reduced, these species will no longer survive. The opposite of this can occur when excess water is entering a river, for example through increased runoff. Low energy systems then become high energy and displace the species that live there.
A species that is not meant to be found in a particular area is known as an invasive species. Invasive species can be from a different habitat or a different country altogether. Most of the invasive species that we find on our rivers have come from other countries – plants that people have imported for their gardens or animals that have been released for food or by animal rights activists. Control of invasive species requires a lot of time and effort. We are fortunate that we do have a range of methods to manage most of the invasive species that cause havoc on our rivers, but there are still some which we are still struggling to control.
Many of our rivers have been heavily modified over the years as rivers have been used for a wide range of purposes. Physical modification is one of the biggest factors that causes our rivers to be unhealthy. The issues that it can cause range from reducing habitat, preventing migration of mobile species, and even have an effect on the water quality. Where structures and modifications are no longer in use or necessary, they should be removed to allow the river to regain its natural state. Unfortunately, this action is not always taken which means that many of our rivers are over straightened and contain redundant structures. It is possible to return a lot of our rivers to their natural state, through one off projects, but in other cases it is not possible as the river has been changed to protect assets or manage flooding. It is recognised that some modifications cannot be removed without having severe negative impacts both socially and economically.
This is pollution that comes from a single identifiable source. The pollution entering the river could include a whole range of pollutants. Some point source pollution is known about and licences, for example sewage treatment works. Other sources are not licensed, and therefore work needs to be done with landowners to fix the problems that are allowing the pollution to enter the river. Point source pollution is more easily controlled than diffuse pollution as it often only takes one management approach to solve the issue.