Appledore’s Full Pump and Water Control solution
The Brief
Nestled between Rye and Ashford on the Royal Military Canal, Appledore Pumping Station is an Environment Agency asset that has stood watch over Romney Marsh since the late 1940s. For over six decades, the station’s two axial flow pumps — driven by Ruston Hornsby single cylinder oil engines — kept the marsh’s water levels in check, operating far beyond their intended design life. When the machinery was finally deemed inoperable, the pumps and engines were decommissioned. One engine found a second life in a museum, while three temporary submersible pumps held the line while a permanent solution was sought.
The Environment Agency’s requirements for the replacement scheme were stringent. The new pumps had to be fish-friendly, capable of passing 500 litres per second each, and — most critically — had to maintain existing winter drain levels without any alteration to the pumping station forebay. That last condition proved to be the crux of the challenge, and one that would defeat several experienced pump suppliers before a solution was found.
The Solution
The EA turned to ACE. Known for finding solutions others overlook, ACE visited the site and identified an approach that had been consistently missed. Their partners, Pentair Nijhuis — recognised as the hydraulic centre of excellence within the $6.3 billion Pentair Group — modelled the proposal using in-house CFD software. The results were conclusive: a fish-friendly submersible pump could be installed without altering the forebay or compromising the drain’s winter levels. It was the breakthrough the project needed.
With the core engineering challenge resolved, attention turned to flood defence. The Environment Agency required two independent lines of protection, and ACE had well-proven answers for both. For the first line, ACE supplied their HDPE pumped flap valve — lightweight, near-neutrally buoyant, and far more ecologically sympathetic than cast iron equivalents. Its lower head loss reduces energy consumption per cubic metre pumped, while its wider opening significantly lowers the risk to fish during passage.
For the second line, ACE introduced the WaStop — a passive inline check valve installed directly behind the flap valve. With no actuators, no control logic, and minimal maintenance, it was a cleaner alternative to a conventional knife gate. A simple breather pipe prevented vacuum stress on the membrane at shutdown, completing a robust two-line flood defence system.
The Result
All pumps were fitted with variable frequency drives, allowing precise flow control and continuous operation close to peak efficiency. Beyond the energy and carbon savings this delivers, the drives provide a slow, controlled start-up — giving fish that shelter within the bell mouth of the pumps a chance to move clear before full speed is reached. The EA’s South East MEICA team were closely involved throughout, providing technical guidance that ensured every aspect of the scheme met their expectations.
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