Flood management in low-lying areas with a UK first

Flood management in low-lying areas with a UK first

10 March 2018

UK - PBA has led the first, large-scale installation of innovative, fish-friendly Archimedes’ screw pumps in the UK. The installation, on the Isle of Sheppey, took place on the protected Medway Estuary and Marshes site and will prevent flood damage to the surrounding farmland and catchment.

In the past the area has experienced significant flooding that damaged crops, highlighting the importance of a reliable water management system to the local economy. In 2016, the Lower Medway Internal Drainage Board (IDB) appointed PBA to update their ailing pumping station.

PBA evaluated the possibility of an increased capacity pumping station capable of replacing the IDB Bells Pumping Station and upgrading the nearby Mockett’s Pumping Station, owned by the Environment Agency (EA).

The project came with significant environmental challenges. The Medway Estuary and Marshes is not only a UK Site of Special Scientific Interest (SSSI), it is designated as a Special Protection Area (SPA) under an EU Directive for the conservation of wild birds. In addition, it is also a site of international importance in accordance with the Ramsar Convention, an international treaty for the conservation and sustainable use of wetlands.

The area is also a prime habitat for eels. Every year, juvenile eels from the North Sea bypass the pumping station through a purpose-built eel pass, to mature in the freshwater river system before swimming back out to sea through the pumping station as fully-grown eels to breed. This safe passage was a great challenge, particularly given the size of the eels in the area, and the Archimedean screw pump provided a truly fish-friendly solution. Excited by the environmental betterment that the innovative technology would bring, the EA agreed to part-fund the pilot project.

After engaging with a wide group of stakeholders, the necessary assents were gained from the EA, Natural England, the Marine Management Organisation and the local planning authority. Construction began in July 2017, with contractor Breheny Civil Engineering, and the station is due to be commissioned and fully operational by May 2018.

Sean Faulkner, PBA Senior Engineer, commented:

“One of the biggest challenges on this project was to co-ordinate the construction works to ensure minimal impact to the wild birds that use the mudflats and saltmarsh on the foreshore. This required engagement with a number of stakeholders to agree a construction programme that worked around key breeding and overwintering periods while keeping the work progressing efficiently and cost-effectively.”

Commenting on the pump installation, Simon Darch, PBA Equity Director, said:

“We’re very proud of our involvement in yet another landmark project in the sector; not only have we been able to enhance the long-term water level management in the Bells and Mockett’s catchments, but we’ve also introduced leading-edge Dutch technology to the UK through the installation of the first large-scale fish-friendly Archimedean screw pumps. We continue to innovate in the implementation of fish-friendly pumping solutions, and these pumps again offer a step-change on environmental performance and energy efficiency, and a dramatic improvement over the two existing stations that have been replaced.”