Hampstead Heath Ponds
, a vast open area of woodland and grassland in north London, has some thirty ponds on or adjacent to it.
The main Hampstead Heath Ponds were originally dug in the 17th and 18th centuries as reservoirs to meet London's growing water demand. These main ponds are divided into two groups: the three Hampstead Ponds and the eight Highgate Ponds. Both sets of ponds are officially numbered incrementally from South to North, the southernmost pond being Hampstead #1 pond and the northernmost being Highgate #8.
The majority of the ponds on Hampstead Heath are fed by the headwater springs of the River Fleet. Three of the main ponds are now large freshwater bathing/swimming ponds: two designated single sex ; and one for mixed bathing. The bathing ponds aren't the only special-use ponds however, Highgate #3 pond is the Model Boating Pond and it, along with a few other ponds, are open to anglers. A number of the other ponds are set aside as wildlife reserves or are purely ornamental.
In 2004, the City of London Corporation, which holds the Heath in trust since the abolition of the Greater London Council in 1986, tried to close the bathing ponds on the grounds that they were an unsustainable drain on their expenses and posed a health risk to swimmers.
The swimmers challenged this and won a victory in the High Court. To defray costs, the Corporation introduced a charge for admission of £2 per session, £1 for concessions. There was some opposition to this on the grounds that swimming there had been free since at least the 1920s, and some ticket machines were vandalised.
Hampstead ponds
The Hampstead Ponds consist of three ponds on the Heath's southwest corner, towards South End Green. Hampstead Pond #3 is the mixed bathing pond, where both sexes may swim.Hampstead ponds #1 is strictly a nature/wildlife pond and Hampstead pond #2 permits angling.
Directly northwest of the mixed bathing pond is the "Viaduct Pond" and west of that is the Vale of Health pond; these are arguably within the flow of the "Hampstead ponds", but aren't officially members of the group.
Highgate ponds
Highgate Ponds are a series of eight former reservoirs, on the heath's east side, and were originally dug in the 17th and 18th centuries. They include two single-sex swimming pools, a model boating pond, and two ponds which serve as wildlife reserves: the Stock Pond and the Bird Sanctuary Pond. Angling is allowed in some of the ponds, although this may be threatened by proposals to modify the dams.The ponds are the result of the 1777 damming of Hampstead Brook, by the Hampstead Water Company, which was formed in 1692 to meet London's growing water demands.
"Boudicca's Mound", near the present men's bathing pond, is a tumulus where, according to local legend, Queen Boudicca was buried after she and 10,000 Iceni warriors were defeated at Battle Bridge. However, historical drawings and paintings of the area show no mound other than a 17th-century windmill.
Swimming ponds
Hampstead has three different ponds for swimming: one for men, one for women and one mixed. Only swimmers over eight years of age are allowed; those between eight and 15 years old must be in the care of an adult. Winter swimming is sometimes available at the ponds, which remain popular with users.The men's pond had a diving tower, but this was dismantled following an accident in the 1970s and only a low level board remains, along with showers and a small sunbathing and changing area.
Quality of water tests — which comply with EU regulations — are routinely performed on all three swimming ponds, and results are available through the The three ponds are not to be confused with Parliament Hill Lido, built in 1938, now with a stainless steel lining.
In December 2017, the City of London corporation, in charge of running the pools, confirmed that transgender women are allowed to use the women's pool per the Equality Act 2010. Julie Bindel, who uses the pond regularly, criticised the decision to be welcoming towards trans women, although reaction was more positive from other groups.
Twenty-first century work on dams
In 2011, it was announced that the City of London was proposing extensive works on the ponds and dams, which it claimed were necessary for safety reasons in the event of a rare major storm. The proposals included measures to improve the water quality of the ponds as well as improvements to the pipes and weirs that allow water to cascade from one pond to the other.These initial recommendations followed engineers' reports in 2005 that the hydrology of the ponds was poorly understood. These same engineering reports resulted in engineering works in 2006 on the two ponds in the grounds of Kenwood House, to make their overflow structures and dams safer. There was strong opposition from the swimming clubs and the Protect Our Ponds campaign. In 2013 a united campaign was launched called Dam Nonsense to oppose the works, which the campaign claimed unnecessary and in conflict with the Hampstead Heath Act 1871. The campaign included all the groups opposed to the proposals. The work on the Hampstead Heath dams was further complicated by the regulations embodied in the 1975 Reservoir Act, which only relate to three dams on the Heath, and the regulations under the Flood and Water Management Act 2010 which potentially relate to all 14 dams on the Heath. The Heath and Hampstead Society took the engineering decisions of the City of London to judicial review in November 2014: the interpretation of the 1975 Reservoir Act was challenged and thereby the nature of the proposed engineering works to the dams. The case was heard by The Honourable Mrs Justice Lang and a ruling, in favour of the City of London, was issued on 28 November 2014. The judgement also addressed the status of the proposed engineering works relative to the provisions of the 1871 Act, again ruling that the engineers had shown due consideration for the provisions of the Act.
The work went ahead and raised the height of the dams, in the case of the dam above the Men's Swimming Pond by 18 feet. The City of London Corporation said the work should be carried out urgently to reduce danger of flooding in surrounding built-up residential areas in the event of one of the dams bursting. The initial estimate of the number of lives which might be lost, in the event of a dam collapse in an extreme flood event, was over 2000. This figure has been reduced to less than 400, still a large number. However the chance of such an event is one in 400,000 years.
The regulated dams under the 1975 Reservoir Act are the Model Pond and the Men's Bathing Pond in the Highgate Chain. Highgate Number 1 pond would have been covered by the Act but the water level was lowered by the GLC in 1984. In the Hampstead chain, Hampstead Number 1 pond is also regulated under the 1975 Act.