If a system has a positive feedback, then it may have multiple stable states, or attractors, and finite resilience. Traditional techniques to calculate system resilience to outside pressures revolve around identifying the system state at a transition point and then figuring out how far that is from a steady state. An increasing number of hydrological systems with positive feedbacks have been modeled, including peatlands, wetlands, lakes, and saline aquifers. For groundwater, changes in rainfall may lead to a switch in the steadystate groundwater level, even if the rainfall returns to its past values. To date it has been unclear how climate causes a switch between steady states. Using a simple aquifer model, Peterson et al. explored how a catchment switches steady states and the associated groundwater level dynamics.