A modular dike or barrier system includes interconnectable side and corner members having front and rear walls with integrally formed support ribs. Upper, base and side end walls connect and are integral with the front and rear walls. Each of the front and rear walls extends at an acute angle relative to the base wall that is configured to rest against a substratum. The inward acute angle allows for containing and redirecting a surge flow inwardly within an area contained by the barrier system in a direction away from the members. The members are generally plate-like and are configured to allow for horizontal stacking on the substratum. Members can include a selectively collapsible support assembly configured to be retained at central bodies of the respective members and to limit interference during stacking and transport of the members.