Amwell is a large nature reserve at the confluence of the Ash and the Lea, managed by Herts & Middlesex Wildlife Trust. It is made up of former gravel pits that have been restored to a diverse wetland nature reserve. It supports internationally important numbers of wintering wildfowl, along with outstanding communities of breeding birds and of dragonflies and damselflies. For more information click here.
Public footpaths run alongside much of the Ash, especially the stretch from Mardocks Mill to Hadham Ford.
Please check the relevant OS map for details of public rights of way.