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Hanningfield Reservoir

Giffords Lane, Chelmsford, Essex CM3 8HX


A Great Fishing Venue and Nature Reserve

Facts about Hanningfield Reservoir

Hanningfield reservoir celebrated its 50th birthday in September 2007.  Primarily an essential water source for homes and businesses in Essex, the reservoir is well-known to anglers, walkers and wildlife enthusiasts in the region.

1) The reservoir covers the ancient hamlet of Peasdown.


2) Before the reservoir was built, the area was called the Sandon Valley.

3) The main dam is a mass of earth with a puddle clay core and is around 1.25 miles long.

4) The dam straight was the longest in Europe when built.

5) One earth moving machine was left in the reservoir and covered in concrete.

6) The maximum depth of water is 16.76 metres (55 feet).

7) The average depth of the water is 7.62 metres (25 feet).

8) The length of the perimeter is approximately 6 miles.

9) The reservoir took five years to build.

10) At 100% the reservoir storage is 26075 million litres, the equivalent of 10,430 Olympic-sized swimming pools.

11) Hanningfield is the second largest reservoir in Essex.

12) The number of staff working out of the Hanningfield site is 326.

13) The longest serving employee working at Hanningfield has been there for 46 years.

14) Water is pumped nine miles from the rivers Blackwater and Chelmer to fill the reservoir.

15) There are no buildings left under the reservoir.

16) W&C French were the main contractors for building the reservoir.

17) Hanningfield reservoir was built by the South Essex and Southend Waterworks companies and work started in 1951.

18) The water treatment works went into production in August 1956.

19) The works were formally opened by the Rt. Hon Henry Brooke, MP, Minister of Housing and Local Government, in September 1957.

20) The reservoir cost approximately £6m to build in 1957.

21) The highest temperature ever recorded at the reservoir was 36.5°C on August 11th, 2003.

22) The wettest year at the reservoir was in 1960 - 789.2mm of rain fell.

23) The average annual rainfall (1960-2006) is 571.4mm.

24) The longest period without rainfall was for 36 days from 22nd July - 26th August 1976.

25) The lowest reservoir level was in the first week of November 1996 when it was 39.2% full.

26) When the reservoir was first built it took 200 days to fill.

27) The reservoir stocks 50,000 fish each year.

28) Television personality Chris Tarrant, footballer David Seaman and cricketer Keith Fletcher have all fished at Hanningfield reservoir.

29) The reservoir has a fleet of 40 fishing boats, two rowing boats and one speed boat.

30) There are two angling clubs based at the reservoir.

31) The reservoir used to have a water quality monitoring station called the ‘iron lady’ which has now been turned into a raft for terns.

32) The newest addition to the facilities at the reservoir is Café on the water which opened in Easter 2007.

33) The biggest fish caught to date stands at 24lb 1oz and was caught by John Hammond in 1998.

34) The reservoir played host to the 2nd leg of the prestigious 1999 European Fly Fishing Championship, won by team Hanningfield.

35) There are over 250 acres of woodland around the reservoir and the treatment works which includes some notable large oak trees.

36) There are four woods around the reservoir – Chesnut, Peninsula, Well and Hawkswood.

37) Hanningfield Nature Reserve was first set up in 1992.

38) The Essex Wildlife Trust Visitors’ Centre, which is next to the reservoir, was opened in 2000.

39) There were 46,500 visitors to the Essex Wildlife Trust Visitors’ Centre during 2006 / 2007.

40) There are four bird hides overlooking the reservoir.

41) The reservoir has a birdwatchers’ den called Rawl Hide.

42) Hanningfield reservoir is designated as being very important for seven species of duck.

43) Names of the buildings demolished to make way for the reservoir include Fremnells, Giffords & Pynnings.

44) When full, the reservoir has 200 continuous days’ storage.

45) It serves people in Southend, the London Boroughs of Barking, Dagenham, Redbridge, and the Thurrock area.

46) The water held there goes on to supply 540,000 homes which is about 1.5 million people.

47) In the winter, when there is plenty of water in the rivers, up to 240 million litres of water a day is pumped in to the reservoir, whilst 150 million litres of water a day is drawn out all year round.

48) The name of Hanningfield goes back a long way.  It means a portion of cleared forest land which was once owned by the family Hann or Ham, who was thought to be a Saxon tribal leader.

49) The reservoir is covered by a Bird Sanctuary Order.

50) Hanningfield treatment works can produce a maximum 225 million litres a day which is over 50% of the average daily demand for Essex.