Drainage Districts in Wales and Scotland

Local Water Management

Both Wales and Scotland have areas where watercourses and drainage infrastructure are collectively managed with the input of the local community.


There are twelve internal drainage districts in Wales:

Afon Conwy IDD, Afon Ganol IDD, Ardudwy IDD, Borth IDD, Dysynni Valley IDD, Glaslyn-Pensyflog IDD, Gwent IDD (including Caldicot & Wentlooge and Lower Wye), Harlech & Maentwrog IDD, Llanfrothen IDD, Mawddach & Wnion IDD, Powysland IDD, and Tywyn IDD.

Each is administered by Natural Resources Wales and has an Advisory Group consisting of representatives of those land occupiers and local authorities who fund the water level management work within the internal drainage district.

Contact Wales’ Internal Drainage District Advisory Groups


The Pow of Inchaffray Drainage Commission is the only local body in Scotland with a specific purpose to manage water levels. It was established by an Act of the Scottish Parliament in 1696 to manage the Pow of Inchaffray, a drainage network that flows into the River Earn near Crieff in Perthshire. Today the Commission’s role remains working to prevent flooding of low lying land in Strathearn, operating under the Pow of Inchaffray Drainage Commission (Scotland) Act 2019.