They are an integral part of the 2017 Regulations (see CIS Guidance 20, paragraph 3.1) and their use should be an integral part of river basin planning.
Maent yn rhan hollbwysig o Reoliadau 2017 [ 9 ] a dylai’r ffordd y cânt eu defnyddio fod yn rhan hanfodol o waith cynllunio basnau afonydd.