# Non-erodible Bed¶

Non-erodible bed can be specified in the morphological module to represent some non-erodible coastal structures such as breakwaters, sea walls, and concrete constructions. An erodible layer with a thickness of $$Z_s$$ is defined in a computational domain. The non-erodible condition can be described as

(1)$P = \bar{P} - 0, \hspace{1cm} \bar{Z}_b \leq Z_s$