Diglis Penstocks – Unlocking the Severn
The Brief
The Diglis Fish Pass project in Worcester, initiated in September 2019, aimed to create an infrastructure allowing the migration of twaite shad upstream for spawning. This initiative is part of Unlocking the Severn, a comprehensive river conservation project led by Canal & River Trust in collaboration with Severn Rivers Trust, the Environment Agency, and Natural England. Kier took the lead in executing the construction of fish passes on the River Severn for this ambitious endeavour.
The fish pass design comprises a series of ascending pools facilitating the free movement of fish from a lower level downstream to a higher level above a man-made weir. ACE’s role in the project involved providing essential control structures for the fish pass, specifically, the installation of four penstocks.
The Solution
Penstock Installation for Fish Pass Control:
ACE played a vital role by installing four penstocks at the Diglis Fish Pass site. Two penstocks were strategically positioned to regulate water levels within the fish pass. These penstocks, measuring 2.5m x 1.5m with a 5.4m frame height, are operated using hand-held spindle drivers. Additionally, two extra penstocks were installed on each side of the main fish pass to create an attraction flow, encouraging fish to enter the pass.
Unique Penstock Design:
One of the project’s distinctive challenges was the need for four side-sealing penstocks while maintaining an open channel configuration. Typically, this requirement would demand the construction of a headwall to support the top sealing face. ACE innovatively designed a bespoke penstock featuring a unique back plate and support structure, facilitating effective four-side sealing without the need for a headwall.
Cost-Saving Flush Invert Penstock Design:
ACE introduced a cost-saving element to the project with their unique flush invert penstock design. Unlike conventional penstock installations that necessitate additional formwork, ACE’s design eliminates the need for extra steps like cutting slots, formwork installation, grouting, and waiting. The penstock can be securely mounted with chemical anchors, streamlining the installation process.
The Result
Functional Fish Pass Control Structures:
The implemented penstocks successfully control water levels within the fish pass, contributing to the overall functionality of the Diglis Fish Pass. The ascending pools and control structures enable twaite shad to migrate freely, supporting the project’s goal of enhancing fish movement and spawning opportunities.
Innovative Penstock Solutions:
ACE’s innovative penstock solutions, including the unique design accommodating four-side sealing without a headwall and the cost-saving flush invert design, proved effective in addressing specific project challenges. These solutions not only meet functional requirements but also contribute to efficiency and cost-effectiveness.
Achievements
01
Contribution to Unlocking the Severn Project
ACE’s involvement in the Diglis Fish Pass project marks a significant contribution to the broader Unlocking the Severn initiative. By providing essential control structures, ACE plays a key role in advancing the goals of river conservation, fish migration facilitation, and ecosystem enhancement along the River Severn.
02
Efficient and Cost-Effective Engineering
The bespoke penstock design and cost-saving measures implemented by ACE showcase the company’s commitment to efficient and cost-effective engineering solutions. These innovations contribute to streamlined processes, reduced expenses, and overall project success.
03
Collaborative Success
ACE expresses gratitude to all project stakeholders for their collaborative efforts, emphasizing the significance of teamwork in achieving success. The Diglis Fish Pass project stands as a testament to effective collaboration, innovative engineering, and environmental stewardship. For more details, visit www.unlockingthesevern.co.uk.
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