| Hanningfield Reservoir facts | DID YOU KNOW? Hanningfield reservoir holds 26 billion litres of water which is the equivalent of 6 billion gallons. That's enough for everyone in the world to have a one gallon bucket each. The water drawn out of the reservoir only lasts about 200 days, so in theory it is filled up and emptied twice every year. |
Hanningfield reservoir was completed in 1957 to serve the growing population of Essex which is the driest county in the UK. Before it was built it was called the Sandon Valley, when the reservoir was developed they built a large dam wall and pumped the water in from the River Blackwater and the River Chelmer. 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. The water held there goes on to supply 540,000 homes which is about 1.5 million people. It serves people in Southend, the London Boroughs of Barking, Dagenham, Redbridge, and the Thurrock area. So how clean is the water in the reservoir? The water contains nitrates, phosphates, bacteria and viruses. It stays in the reservoir for 200 days and gradually the quality improves. It then goes through a very complex cleaning process. How is it cleaned?
 | | The reservoir is home to lots of birds |
The water is drawn into the plant, and ozone is added to kill off the algae. Then iron is added and the chalk in the hard water is removed. Lime is added to soften the water, before it gets passed down through beds of fine sand. The water has more ozone added to it and breaks down the pesticides. It then passes water through carbon which acts as a huge water filter, finally chlorine is added and the water gets pumped off to peoples homes. How does local wildlife benefit? Several different species of birds live and breed around the reservoir. Geese, Coots, Moorhens, and Ducks can be found. There is also a bird sanctuary, and a wildlife visitors centre run by the Essex Wildlife Trust. The reservoir itself is stocked with trout and people can go fishing. | 
