Fish Passes on River Abstractions/Impoundment Structures

September 15, 2020

If you are planning to construct a structure that will obstruct a know migratory route, you will need a fish pass.

The free passage of migratory fish is a key requirement of the Water Framework Directive. Installing weirs, dams, culverts and other obstructions in waterways to manage river abstractions, can cause disruption to the movement of fish and other aquatic fauna. SEPA, the Environment Agency and Natural Resources Wales have a range of statutory powers to improve fish movement to support and promote the diversity and abundance of fish and eels in our watercourses.


Do I need to install a fish pass?

If you plan to construct, a weir to manage river abstractions, and it obstructs a known migratory route, then the simple answer is yes. If you operate an existing impoundment structure, then you could be required to install a fish pass. If you already have a fish pass in place, maintenance and ensuring its fit for purpose are likely to be your responsibility.


What are the options? 

There are several factors to consider when designing, installing and maintaining an effective fish pass. Each river system is different; therefore, knowledge of the hydrology, geomorphology and suitable engineering solutions are required. Solutions that require in-river works will be subject to several regulatory considerations, potentially including:



A high level of regulatory liaison will be required to ensure that the requirements of operators are balanced against regulatory requirements, particularly where works are planned on statutory main rivers. Importantly, the final solution must take account of the practical and financial considerations associated with any in-river works.


Our surface water team are uniquely placed to help you assess any requirements for improving fish passage and liaising with the regulators to achieve the most appropriate solution. If you are interested to learn more, get in touch with our technical lead, Lee Clarke at LeeClarke@envireauwater.co.uk or call us on 01332 871 882.


Share

Tom Onslow joins Envireau Water

By Rachael Plant • June 12, 2025
Envireau Water is delighted to welcome Tom Onslow to our North Office in Richmond! Tom joined us at the start of the month from Western Australia, where he gained experience working as a Field Hydrogeologist. Prior to this, Tom graduated from Newcastle University with a Master of Earth Science (MEarthSci). Tom is experienced in both field and desk-based activities, including the supervision of water exploration drilling programs, conducting hydrogeological sampling and logging, carrying out pumping tests and analysis and designing and installing groundwater monitoring networks. Tom has also built a strong foundation in technical reporting, having contributed to a wide range of water-related projects, particularly across the mining sector. At Envireau Water, Tom will continue to develop his hydrogeological expertise and provide technical support across a range of sectors both on site and in the office.

Securing your Water Bottling Plant against Climate Change

By Rachael Plant • June 11, 2025
As the threat of climate change continues to grow, the occurrence of extreme weather events is becoming increasingly common across the UK, with the rising frequency of flooding and drought posing significant challenges nationwide. After the recent dry spell experienced across the UK, one thing is clear: climate change is a hazard affecting all industries and it is more important than ever for businesses to take proactive steps to secure their water supplies against these unpredictable weather events. We asked our Principal Hydrogeologist, Shona Symon , for her thoughts on the matter within the bottled water industry. Shona, can you explain the importance for operators to safeguard their water bottling plant against the impacts of climate change, and what challenges may arise if not adequately protected?

Bethan Joule joins Envireau Water

By Rachael Plant • June 10, 2025
We're thrilled to welcome Bethan Joule to our growing Shrewsbury office! Bethan joins us as a Senior Hydrogeologist, bringing over six years of experience in technical roles at Wardell Armstrong. Prior to this, she graduated from Queen’s University Belfast with an MSc in Environmental Engineering in 2019. Bethan is experienced in preparing abstraction licence applications, delivering Hydrogeological Risk Assessments (HRAs), and overseeing a wide range of site investigations — including borehole drilling and hydrogeological testing - across multiple sectors, including minerals, waste, and construction. At Envireau Water , Bethan will be continuing to provide similar hydrogeological services to our extensive client base whilst also developing complimentary skills across our broad range of sectors.
Show More

Tom Onslow joins Envireau Water

By Rachael Plant • June 12, 2025
Envireau Water is delighted to welcome Tom Onslow to our North Office in Richmond! Tom joined us at the start of the month from Western Australia, where he gained experience working as a Field Hydrogeologist. Prior to this, Tom graduated from Newcastle University with a Master of Earth Science (MEarthSci). Tom is experienced in both field and desk-based activities, including the supervision of water exploration drilling programs, conducting hydrogeological sampling and logging, carrying out pumping tests and analysis and designing and installing groundwater monitoring networks. Tom has also built a strong foundation in technical reporting, having contributed to a wide range of water-related projects, particularly across the mining sector. At Envireau Water, Tom will continue to develop his hydrogeological expertise and provide technical support across a range of sectors both on site and in the office.

Securing your Water Bottling Plant against Climate Change

By Rachael Plant • June 11, 2025
As the threat of climate change continues to grow, the occurrence of extreme weather events is becoming increasingly common across the UK, with the rising frequency of flooding and drought posing significant challenges nationwide. After the recent dry spell experienced across the UK, one thing is clear: climate change is a hazard affecting all industries and it is more important than ever for businesses to take proactive steps to secure their water supplies against these unpredictable weather events. We asked our Principal Hydrogeologist, Shona Symon , for her thoughts on the matter within the bottled water industry. Shona, can you explain the importance for operators to safeguard their water bottling plant against the impacts of climate change, and what challenges may arise if not adequately protected?

Bethan Joule joins Envireau Water

By Rachael Plant • June 10, 2025
We're thrilled to welcome Bethan Joule to our growing Shrewsbury office! Bethan joins us as a Senior Hydrogeologist, bringing over six years of experience in technical roles at Wardell Armstrong. Prior to this, she graduated from Queen’s University Belfast with an MSc in Environmental Engineering in 2019. Bethan is experienced in preparing abstraction licence applications, delivering Hydrogeological Risk Assessments (HRAs), and overseeing a wide range of site investigations — including borehole drilling and hydrogeological testing - across multiple sectors, including minerals, waste, and construction. At Envireau Water , Bethan will be continuing to provide similar hydrogeological services to our extensive client base whilst also developing complimentary skills across our broad range of sectors.

World Environment Day 2025

By Rachael Plant • June 5, 2025
Across the globe, plastic pollution is becoming an increasingly crucial topic, with an estimated 400 million tonnes being produced every year world wide. While the focus is often on visible plastic (including bottles, bags, and packaging), a growing body of research is turning its attention to the invisible threat of microplastics and emerging contaminants, which are increasingly finding their way into water sources, food chains and even the air we breathe.  What are microplastics? Microplastics are a growing threat to the health of our planet. Despite being barely visible, these tiny plastic particles account for roughly 8% of global plastic waste, a number that is set to increase in the coming years.
Show More