Pool restoration
Thanks to funding awarded from National Highways under the Environment and Wellbeing Designated fund, we have undertaken vital restoration work to the pool at Berrington.
The pool was designed by ‘Capability’ Brown and, along with the parkland and garden, was his final complete estate before his death in 1783. The pool is a Site of Special Scientific Interest (SSSI) due to the large heronry which nests on the island every year.
Why was the pool restored?
The pool was in urgent need of restoration; the biodiversity of the pool had been adversely affected over the years due to the spread of reed cover and increase in the silt bed. Large carp were the dominant fish species, and predated on smaller fish which are a key food source for herons. Heron numbers had sadly declined over the last 10 years. It was therefore vital that we intervened to ensure the survival of the SSSI and the heronry.
Therefore, we aimed to:
- Enhance the biological integrity of the pool, including the SSSI, and improve habitat for the heronry.
- Reduce tree cover around the pool to provide more open water conditions and enhance aquatic diversity.
- Restore pool and improve water quality through silt control and aquatic plant management.
- Restore historic views across landscape.
What restoration work took place?
Restoration work began in November 2021, when the fish were removed from the pool. Native species of fish were kept in holding tanks to be returned to the pool and carp were rehomed. The pool was then drained of water and desilted over the course of several months. This involved four diggers which silt from the bed of the pool to an area of Moreton Ride. A channel was also created around the island to allow water to circulate. Vegetation stopping the circulation of water was removed. Trees in Moreton Ride which were causing debris to accumulate in the pool were thinned.
The pool was then slowly refilled with rainwater. When the level was sufficient, native species of fish were reintroduced to the pool. These species include rudd, common roach, European perch and northern pike, all of which are a brilliant source of food for herons and other waterfowl.
What did we discover during the restoration?
The pool restoration project was a fantastic opportunity to understand what wildlife relies on the pool. During the project, ecologists Will Watson and Giles King-Salter, undertook a survey of the wildlife present in the pool. They were able to identify 35 different types of invertebrates. One of the most exciting invertebrates found in the pool was swan mussels. These mussels rarely grow bigger than 180mm, however the largest rescued from Berrington’s pool was 203mm! There are two of shells of swan mussels on display in the mansion at present, giving a sense of just how large they grew in Berrington’s Pool.
Also identified were 38 species of bird, including the great white egret, water rail, green sandpiper and kingfisher.
The footprints of an otter were also discovered whilst work was undertaken, suggesting that they also use the pool to source food.
What next?
We hope that over time the biological integrity of the pool will increase.
It will take some time for the pool to return to its full depth and for the mud caused by heavy machinery to settle down. We will continue controlling the tree cover and vegetation in and around the pool. Water samples from the pool will be tested regularly to identify whether the water quality has improved. The numbers of birds, and especially herons, will also be monitored and should provide an indication of whether the restoration was successful.
Where silt has been deposited from the pool in Moreton Ride, we are going to work with ecologists to turn this into new habitats and further increase the biodiversity of Berrington’s parkland.
For more information, please email us: berrington@nationaltrust.org.uk