Brasside Pond is a Site of Special Scientific Interest

Site of Special Scientific Interest

A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...

 just north of the city of Durham

Durham

Durham is a city in north east England. It is within the County Durham local government district, and is the county town of the larger ceremonial county...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. The site occupies an area of former clay pit

Clay pit

A clay pit is a quarry or mine for the extraction of clay, which is generally used for manufacturing pottery, bricks or Portland cement.The brickyard or brickworks is often located alongside the clay pit to reduce the transport costs of the raw material. These days pottery producers are often not...

s sandwiched between the River Wear

River Wear

The River Wear is located in North East England, rising in the Pennines and flowing eastwards, mostly through County Durham, to the North Sea at Sunderland.-Geology and history:...

 to the south and Frankland Prison

Frankland (HM Prison)

HM Prison Frankland is a Category A men's prison located in the village of Brasside in County Durham, England. Frankland is operated by Her Majesty's Prison Service.-History:...

 to the north and is split into two parts by a disused railway line.

North of the railway, adjacent to the prison, are two large ponds, the result of flooding of the old clay workings. These are one of the largest expanses of unpolluted open water, reservoirs excepted, in County Durham

County Durham

County Durham is a ceremonial county and unitary district in north east England. The county town is Durham. The largest settlement in the ceremonial county is the town of Darlington...

 and are the most important breeding site for wildfowl in the county.

The portion south of the old railway is a mix of small ponds and fen

Fen

A fen is a type of wetland fed by mineral-rich surface water or groundwater. Fens are characterised by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients...

, surrounded by acid grassland.