This article was originally published by Able Instruments in November 2025.
The Grange is a holistic estate nestled in the heart of Hampshire. The main entrance drive shows off the beautiful parkland set in the gently rolling Candover Valley.
The Grange and its park have a colourful history stretching back several hundred years – encompassing a royal tenant, a succession of banking families, requisition during the 2nd World War, and earlier this century the addition of a 570 seat theatre used for an annual opera festival.
In the 1660s a handsome brick mansion was built on the site of the current house for the Henley family who also began to lay out the park.
The Baring family, when John Baring (now 7th Lord Ashburton and grandson of the ancestor who had sold it) acquired it in an auction in Winchester in 1817
The house remained vacant and deteriorating but in view of its architectural significance it was taken into the guardianship of the Department of the Environment (now English Heritage) in the 1970s, although the freehold remains with the family.
Watercress, Nature’s Living Filter
The Grange estate in includes a notable area of watercress beds, which are characteristic of the clear chalk streams in that part of the county. Watercress beds don’t just grow a crop — they also act as natural biofilters, improving water quality as it flows through them, striping out nitrates and phosphates. The staff see the estate as a living system rather than a business alone, balancing productivity, ecology and well-being.
For this pollution reduction the estate obtains Water Quality Credits which can be traded for money with entities such as wastewater treatment plants, industrial dischargers, and sometimes agriculture, much like the emissions trading schemes employed in the oil and gas industry.
The Role of Open Channel Flow Metering
A watercress filtration system is only as effective as its flow management. Accurate open channel flow metering is therefore essential for both performance and accountability.
Watercress grows best in consistent, shallow, and gently moving water. Open channel flow meters ensure that the right flow rate and water depth are maintained — slow enough for sediment capture and nutrient absorption, yet fast enough to prevent stagnation or plant damage.
Continuous flow data allows engineers to measure treatment efficiency precisely.
By comparing inflow and outflow rates alongside water quality samples, municipalities can quantify pollutant removal, validate performance, and demonstrate compliance with environmental standards.
Real-time metering data supports adaptive management. During heavy rainfall or drought, operators can adjust gates or weirs to stabilise flow and protect both the watercress beds and downstream systems — ensuring reliable operation year-round.
In a climate of environmental regulation and public transparency, accurate flow data provides verifiable evidence of performance. Local authorities can report clear, data-backed outcomes to regulators, funding bodies, and the community, strengthening trust and supporting long-term sustainability goals.
Considering the importance of accurate flow metering, The Grange’s Property Maintenance Assistant, Ashley Haynes, approached Able Instruments for their assistance in specifying the right equipment. Able recommended the Hach Model FL900 Open Channel Flow Logger and the AV9000 Submersible Sensor.
The Submerged AV Sensor is a rugged 1 MHz Acoustic Doppler sensor built to deliver precise and reliable flow measurements in real-world conditions. Its integrated pressure transducer tracks flow levels, while automatic temperature and velocity compensation ensures consistent accuracy without manual adjustments. Paired with the AV9000 Analyzer Module, it tackles even the most challenging flow environments through advanced signal processing and filtering. On-site diagnostics, including real-time Doppler spectra display, let you verify performance before leaving the location. Together, these features provide confidence and peace of mind for the customer, helping to capture accurate data efficiently and ensuring the system is operating at its best from the start.
To Summarise
The Grange Hampshire is extremely pleased with the performance and reliability of the Hach Open Channel flow meters installed across its watercress beds. These advanced instruments have delivered accurate and consistent flow measurements, playing a crucial role in monitoring and managing water usage. Their precision has been particularly valuable in providing a trusted fiscal measurement for water credits, ensuring compliance and supporting sustainable water stewardship. By integrating Hach technology into its operations, The Grange Hampshire has enhanced both the efficiency and accountability of its water management practices.