In Internal Drainage Board (IDB) is a local public authority that manages water levels. They are an integral part of managing flood risk and land drainage within areas of special drainage need.

The Medway IDB’s, under the Land Drainage Act 1991, exercise general powers of supervision over all matters relating to water level management within their districts. Key watercourses within their districts have been adopted by the Board for maintenance purposes although their powers are permissive. Remember the ultimate responsibility will always come back to the landowner.

IDB’s are not, however responsible for watercourses designated as main rivers, the supervision of these watercourses is undertaken by the Environment Agency.


The Lower Medway Internal Drainage Boards are two of the five other Internal Drainage Boards in Kent.

To give you a brief insight into what an IDB is please refer to the ADA 2017 Introduction to IDB’s booklet.

To also get an idea of what all the other Flood Risk authorities do and what your own responsibilities are also refer the Environment Agencies Living on the Edge booklet.