Open systems where the energy of operation comes from outside, and moves across, the system boundary. Any change in energy or mass causes both the processes and their related landforms to adjust in order to maintain equilibrium in the system. The stability of a geomorphic system will depend on whether the changes are linear, non-linear, or threshold-related, and whether the effects of change are locally damped or propagate through the system (Harvey (2007) Geomorph. 84, 3–4).
Subjects: Earth Sciences and Geography.