Approximately 20 years ago, to the south of Bishop Middleham village, a lake began to develop as a result of groundwater flooding. Now known locally as Castle Lake, this water body covers an area of 13 ha (33acres). A report to evaluate the ecological value of Castle Lake within a regional and national context has been completed and available for viewing.

Castle Lake is a highly significant inland wetland supporting a wide range of flora and fauna, not only regionally, but also in the case of select species, nationally important numbers of birds.


1. To promote for the benefit of the public, the conservation, protection and improvement of the physical and natural environment by promoting biological diversity of the area in Bishop Middleham, County Durham, know as Castle Lake.

2. To advance the education of the public in the conservation, protection and improvement of the physical and natural environment.



BIRDS A total of 183 bird species recorded

It is for its birdlife that Castle Lake is quite rightly renowned. During summer and autumn, it is quite possible to see 60-70 species at the site.



FLORA A rich grassland-significant flora

After a comprehensive inventory of semi-natural grasslands, Castle Lake was identified as a particularly rich grassland habitat that supported a wide range of significant flora.



FAUNA 44 botanical species recorded in 2007

Given the wet habitat of Castle Lake and the availability of multiple shallow pools, there are a wide range of species of damselflies and dragonflies, newts, toads, frogs, plus birds.


Registered Key Holders

Meters above sea level

Years since 1st formed

Meters maximum depth

A viewing hide!

Durham Bird Club

Durham Bird Club has developed Castle Lake to attract a wide range of bird species with the addition of breeding islands, scrapes, wet ditches, reed beds and hedgerow systems.

The surrounding pasture is primarily grazed throughout the year with fields also cut for silage, although in within the last 20 years, these fields have also been cultivated for cereal and root vegetable production. Some fields, for example ‘Castle Field’ to the north of the site, also include areas of exposed limestone rock because of historical quarrying activities and the existence of ruined buildings. This provides suitable habitat for specialist flora associated with magnesian limestone. The old ‘deer park’ wall, albeit in need of substantial restoration, neatly surrounds the land tenure.

This ancient wall is full of nooks and crannies amongst the crumbling masonry, offering an interesting habitat for invertebrates, small mammals and birds, interspersed with scattered scrub and individual hawthorn. A modern sewage water treatment works serving Bishop Middleham is now situated in the central north-west corner, and amongst the water treatment facilities are cut grassland and occasional shrubs.

A butterfly and dragonfly survey of this site in 2010 concluded that the sewage treatment works had little environmental value, especially with regards to botanical interest, owing to the mown grassland of the main operational zone and the heavy grazing taking place in the site’s redundant area (Eales, 2010).

Help us!

We'd like you to...

Make Notes
Send Pictures

If you visit the site please record the species of birds you see along with any interesting flore or fauna. Please send the information