Wraysbury Reservoir: A Vital Water Resource and Ecological Haven
Located in Surrey, just west of the M25 and situated directly beneath the western approach path of Heathrow Airport, the Wraysbury Reservoir serves as a critical component of London's water infrastructure. This engineered body of water balances industrial utility with significant biological importance, providing both essential resources for the city and a sanctuary for diverse wildlife.
Key Facts
- Purpose: Primary water supply reservoir for London.
- Capacity: 34,000 million litres (34 Gl).
- Operator: Owned and operated by Thames Water.
- Conservation Status: Designated as a biological Site of Special Scientific Interest (SSSI).
- Special Use: Hosts the National Physical Laboratory's Open-Water Test Facility.
Engineering and Operations
Construction of the reservoir began in 1967 and was completed in 1970 by W. & C. French. The facility is designed to hold a massive volume of water to ensure a steady supply for the metropolitan area. To maintain this supply, Thames Water pumps 400 million litres of water daily from an inlet located at Datchet on the River Thames.
The reservoir's infrastructure includes extensive earthen banks. To ensure these banks remain accessible for inspections and to keep the grass naturally trimmed, Thames Water employs a flock of sheep for grazing.
[ไม่มีภาพประกอบ]Technical Specifications
The engineering of the Wraysbury Reservoir is defined by precise parameters to manage water pressure and storage efficiency. The maximum depth of the water reaches 21 metres, while the perimeter of the bank extends for 5,700 metres.
| Parameter | Value |
|---|---|
| Water Storage Volume | 35 million m³ |
| Surface Area | 202 hectares |
| Maximum Water Depth | 21 m |
| Top Water Level (above ordnance datum) | 31.1 m |
| Maximum Bank Height (above ground) | 17 m |
| Bank Perimeter | 5,700 m |
Scientific and Military Utility
Beyond its role in water utility, the reservoir is home to the National Physical Laboratory's Open-Water Test Facility. This specialized site is utilized by the Ministry of Defence for the calibration and testing of sonar systems—technology used to detect objects underwater using sound propagation. The facility also provides testing services for various civilian commercial customers.
Ecological Importance and Conservation
The Wraysbury Reservoir is recognized as a biological Site of Special Scientific Interest (SSSI), a designation given to areas of high conservation value. Covering 205.6 hectares (508 acres), it was officially notified as an SSSI in 1999.
The site is part of the South West London Waterbodies Ramsar site (a wetland of international importance) and is also a Special Protection Area. These designations highlight its role in supporting avian populations. The reservoir is particularly noted for hosting nationally important numbers of wintering cormorants, great crested grebes, and shovelers, as well as supporting significant populations of gadwalls.
Frequently Asked Questions
Who manages the Wraysbury Reservoir?
The reservoir is owned and operated by Thames Water.
Where does the reservoir get its water?
Water is pumped daily from an inlet at Datchet on the River Thames, with approximately 400 million litres moved each day.
What is the purpose of the sheep on the reservoir banks?
Thames Water maintains a flock of sheep to keep the grass short, which facilitates easier inspections of the earthen banks.
What makes the reservoir scientifically significant?
It is a biological Site of Special Scientific Interest (SSSI) and a Ramsar site, providing critical habitat for wintering birds like cormorants and great crested grebes.
Is the reservoir used for anything other than water storage?
Yes, it hosts the National Physical Laboratory's Open-Water Test Facility, used by the Ministry of Defence and commercial clients for sonar system testing and calibration.