Almshoebury Swallowhole

Almshoebury Swallowhole is a unique hydrological feature located at the bottom of a narrow valley near Almshoebury farm.

During times when groundwater is at a moderate level a steam enters the site from the south but disappears down the swallowhole on the eastern boundary. The water continues underground and eventually forms a tributary to the river Purwell at Hitchin.

At times of very high groundwater, there is too much to drain into the swallowhole and it forms a deep lake.

The landforms created over thousands of years of action by water have created varied plant communities.

In the south of the meadow is an area of wet woodland of mainly ash, oak and hornbeam. On the sides of the valley the grassland has remained unaffected by agricultural chemicals. It as a rich variety of grassland plants including Birds-foot-trefoil, Self Heal and Meadow Vetchling.

Around the swallowhole itself are a range of wetland plants such as Water Pepper, Pink Water Speedwell and Mint.