Mud and Swale

Mud noun - Water soaked soil; soft wet earth.

Swale and mud are semantically related In some cases you can use "Swale" instead a noun "Mud".

Swale noun - A low area (especially a marshy area between ridges).

Mud and swale are semantically related in swamp topic. You can use "Mud" instead a noun "Swale", if it concerns topics such as wet land covered with vegetation.