The primary benefits of a segmental retaining wall over a poured concrete wall or a rock and mortar wall are as follows: Segmental walls are designed to allow for the release of water which prevents hydrostatic pressure (water pressure). Being that they are dry-stacked without mortar, they have the ability to be much more porous and allow for greater water permeability, which will ultimately aid in the life and structure of the wall. Additionally, segmental retaining walls are exactly as stated, they are segmental. The reason this is an advantage over poured concrete walls or rock and mortar walls is that the wall allows for movement in the earth without impairing the integrity or the structure of the wall. A poured concrete wall or a rock and mortar wall is a rigid system that can crack when the ground moves or heaves.