Investing in the River Cleddau
As a company, we depend on the environment for the water and wastewater services we provide. We take our responsibilities to protecting the environment seriously and we invest around £1 million a day in improving and maintaining our networks.
We also know that customers want us to do more, especially to help protect the quality of our rivers such as the Cleddau. This is why we are working in the Cleddau catchment area to improve our assets. On this page you will find some information on the challenges we face, our five-year investment plan, and the funding available to support the community with good causes in the area.
What’s the problem?
The quality of our main rivers is monitored by Natural Resources Wales. There is concern about the river water quality in parts of the Cleddau as they’re not achieving what’s called ‘good’ ecological status. This means that there are too many chemicals in the river such as ‘phosphorous’ which can cause algal blooms which can affect the amount of oxygen available in the water and harm wildlife.
What’s causing this?
There are several factors which can increase phosphate levels. This includes how we treat wastewater before it’s returned to the environment. Our modelling of the River Cleddau for example shows that our assets (i.e. our treatment works, Storms Overflows or SOs) are responsible for around 11% of the phosphates going into the Eastern Cleddau, with SOs only responsible for 2%. On the Western Cleddau treated wastewater discharged from our Wastewater Treatment Works (WwTW) is responsible for around 22% of the phosphates going into the Eastern Cleddau, with SOs only responsible for 5%. The remainder of the phosphate entering the two rivers is caused by other factors such as rural land use and animal faeces, urban surface water drainage, misconnected drains, as well as private septic tanks.
However, we understand that this is an important matter for local residents, and we are committed to playing our part to doing what we can to reduce our impact on the river Cleddau.
Our investment
Over the next five years (2025 – 2030), we’re investing in approximately £60 million in the wider Cleddau catchment to improve the way our treatment works operates and also reduce the number of spills that come from our Storm Overflows. To achieve this, we will be working at different sites simultaneously.
What are we doing?
We have a significant amount of work to do which will take time, but we are committed to making continuous improvement year on year. That’s why our work will be carried out over the next five years.
The areas we’re currently working on so far are:
We’re currently carrying out work at Rosemarket Wastewater Treatment Works to improve the quality of water released into the nearby watercourse, which feeds into the River Cleddau.
As part of these improvements, we will be refurbishing the biofilter. Biofiltration is a biological method of wastewater treatment that uses a bed of media, such as sand or gravel, coated with a biofilm of microorganisms. These microorganisms break down pollutants as the wastewater passes through the filter, resulting in cleaner, treated water. This is an environmentally friendly and effective way to remove contaminants.
In addition to benefiting the environment, these upgrades will also ensure the waste network has sufficient capacity to manage increased flows. This will help reduce the risk of network failure and support the needs of the wider community as the area continues to grow.
The investment is scheduled for completion by October 2025. However, there may occasionally be factors beyond our control that could affect the scope of the work. If that happens, we’ll let you know in advance.
We’re upgrading our assets at Letterston Wastewater Treatment Works to improve the quality of water released into the environment by incorporating the latest technology and equipment.
A key part of the upgrade involves introducing a new treatment process to remove phosphates from the treated wastewater. Phosphates can contribute to algal blooms, which negatively impact water quality and aquatic life. By reducing phosphate levels, we aim to improve the health of the River Cleddau and its surrounding environment.
To support this process, we will be installing ferric and alkalinity dosing systems. Ferric dosing helps bind phosphates, making them easier to remove during treatment, while alkalinity dosing ensures the chemical balance of the water is maintained throughout the process. Together, these systems will enhance the effectiveness of phosphate removal and contribute to more sustainable wastewater treatment.
The investment is scheduled for completion by October 2025. However, there may occasionally be factors beyond our control that could affect the scope of the work. If that happens, we’ll let you know in advance.
We’ve completed the upgrade of Spittal Wastewater Treatment Works (WwTW) in Pembrokeshire.
While the site already treated wastewater from the surrounding area to a high standard, the recent improvements have further enhanced the treatment process.
The project began with preparation works before Christmas 2023 and included the introduction of a new process to remove phosphates from the treated wastewater.
How will the work affect you?
The work will not affect the water or wastewater service but as with any large construction project, there will be times where there will be some noise, construction vehicles, and disruption to traffic in the area but the team will do their best to reduce disruption where they can.
In your area - Keep up to date
For the latest on the project and what’s happening on site, please go to our In Your Area page.
River Pollution
Dŵr Cymru Welsh Water works to protect rivers and other waterways by treating the wastewater from our homes and businesses and safely returning it to the environment. It requires huge amounts of equipment and thousands of kilometres of sewers.
Report to us as soon as possible if you see sewage pollution in a river, stream, or other watercourse. This helps us to protect and enhance our rivers and environment.
Click here for more information.
Community Fund
Did you know that Welsh Water has a Community Fund which your community could benefit from? If you live in an area where work is taking place, and you’re fundraising for projects to benefit the community, click below for more information about our £5,000 Community Fund.
Find out more about the community fund