
Upper Thurne Integrated Drainage Improvements Project
Civil Engineering
Bam Nuttall Ltd
Jacobs UK Ltd
Turner & Townsend
January 2025 – July 2026
The replacement of Horsey pumping station was delivered under Package 1 of the wider Upper Thurne Integrated Drainage Improvements Project. The pumping station directly protects the 792Ha Horsey drainage district (reference CMT028P) and is located only a few metres from the existing pumping station and original Horsey drainage mill, where a pump has stood since the early 18th Century.
Construction of the new pumping station commenced Spring 2025 and was completed in July 2026.
The pumping station features two Pentair VDX1-450 suspended bowl mixed flow “less harm” pumps offering significant increases in efficiency over the current submersible pumps. To deal with climate change and increased severity of rainfall events duty capacity is increased by a minimum 50% with each pump delivering up to 375 litres per second.
The 3.14m deep pumping station “wet well” (intake) is formed from 8.1m long steel sheet piles driven in to the underlying crag group. The sheet piles form both the temporary cofferdam and permanent wet well. The wet well sump, central dividing wall and liner is constructed from in-situ cast reinforced concrete.
The pumps are supported on precast concrete pump support slabs which bear on the wet well concrete liner and central wall. A manually raked trash screen protects the intake from course debris.
The black horizontal timber effect GRP kiosk houses Motor Control Centre, power and telemetry systems. The pumps are controlled by Variable Speed Drives allowing them to deliver a broad range of flows in response to catchment conditions. The telemetry system provides improvements in remote monitoring, control and operation of the station.
The pumping station discharges through below ground PE pipework into Horsey Staithe through precast concrete chambers. The outfall chambers and pipework are designed to reduce discharge velocities, ensuring no detrimental impact on river users.
The system is protected from return flow by lightweight HDPE flap valves at the outfalls and “gate valves” within the wet well.
Both the control building and outfall pre-cast units are founded on steel piles to ensure prevent settlement.
The visual impact of the station has been carefully considered given the sensitive nature of the site through the specification of material colours and plant selection whilst balancing the primary function as a pumping station.

To facilitate the pumping station construction, we undertake enabling works, including ecological mitigation in advance.

Design visualisation of completed Horsey pumping station, showing the inner working of the pumping station

June 2025 - Outfall Piling Works Underway

July 2025 - Piling complete and excavations underway

July 2025 - Intake Concrete Pour

July 2025 - Reinforcing bars within the newly sheet piled and excavated intake

September 2025 - Wet Well with Re-Bar lining, awaiting it's concrete pour

September 2025 - The newly formed concrete intake

October 2025 - The pre-cast outfall in place awaiting further construction

October 2025 - Culvert Excavation

November 2025 - Outfall Pre-cast structures

November 2025 - Intake concrete structure with newly fitted pumps

November 2025 - Aerial of Horsey Site

December 2025 - Intake weedscreen

February 2026 - Kiosk being craned into place

February 2026 - Outfall structure complete and linked back with watercourse

March 2026 - Kiosk and new fencing work underway

September 2026 - Intake Completed

September 2026 - Outfall Completed

September 2026 - Pump Motors

Horsey’s water management has evolved significantly over the centuries. The first drainage mill on the site, known as the “Great Mill,” was built in 1816 to manage water levels and prevent flooding. Prior to this, wind-powered mills such as the smaller smock mill, built around 1812, and older mills like the Waxham Drain Mill, were in use. By the mid-1800s, steam-powered pumps supplemented the wind pumps, with a steam engine installed at Mere Farm in 1863.
In 1900, a Garrett twin-cylinder portable steam engine was added beside the Horsey Windpump which was later replaced with a 55hp Crossley diesel engine pump in 1939. The diesel engine powering the pump was replaced by electric plant in 1957, with the Smithdale turbine pump being retained. This pump lasted for four decades, until it needed to be replaced in 1998.

The Upper Thurne Integrated Drainage Improvement Project will replace or refurbish 11 of the 14 pumping stations within the River Thurne catchment in the Norfolk Broads at Horsey, St Benets, Martham, Potter Heigham, Brograve, Stubb, Catfield, Horse Fen, Repps Staithe, Somerton South, and Thurne.
The current submersible canister pumping stations were typically built in the 1950’s with some housed within far older foundations dating back to the 19th Century. Despite ongoing maintenance to sustain their operation all have significantly exceeded their design life and are unsuitable for further refurbishment.
Collectively the 14 pumping stations protect over 6300 hectares of Broads Internal Drainage Board districts including nationally and internationally designated habitat, 708 properties, local communities, tourism and infrastructure.
Each site features unique challenges with a mosaic of designated habitats including Sites of Special Scientific Interest (SSSI’s), Special Area of Conservation (SAC’s), Special Protection Area (SPA’s), National Nature Reserve (NNR’s) and Ramsar designations as well as significant variations in ground conditions.
The existing pumping stations are generally built in existing raised flood defences, within or adjacent to historic infrastructure.
The presence of active boat yards, staithes, moorings and other tourism such as the National Trust Horsey Wind Pump present a unique set of challenges to the project.

The Upper Thurne Drainage Improvements Project will bring significant benefits to both the environment and local communities: