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 catchment, which includes two of HM Prisons, 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 pumping station. We evaluated the possibility of an increased capacity pumping station capable of replacing the IDB Bells Pumping Station and rationalising the nearby EA-owned Mockett’s Pumping Station, which was also due an upgrade.
The catchment provides a prime habitat for eel, and the asset was a high priority for improvement under the Eels (England and Wales) Regulations 2009. The reconstruction provided an opportunity for upgrading the passage for eel migration. We appraised the viability of the fish-friendly options available, and an Archimedes’ Screw pump was selected. The patented product integrates a casing around the helical screw blade that rotates around the central shaft, thus avoiding the potential for leading edge fish damage associated with traditional screw pumps with a static casing. The product also provides high efficiency and reliability improvements, and an almost silent operation.
The project came with some stringent 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 on the conservation of wild birds. In addition, it has also been designated as a site of international importance under the Ramsar Convention, an international treaty for the conservation and sustainable use of wetlands.
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 and the pumping station is now fully operational.