Toward a theoretical framework for integrated modeling of hydrological change

In an attempt to provide a unified scheme for the simulation of changing behaviours of hydrological systems, a theoretical framework for stationary and non-stationary modelling is presented. The main triggers for hydrological change are reviewed, their impact on the long term properties of the inherent system are analysed and theoretical solutions are proposed for their representation. Model calibration is also discussed along with the impact of hydrological change on simulation uncertainty. Non-stationarity and its simulation are examined as well. We propose a stochastic approach which is general, and allows a comprehensive treatment of uncertainty. The proposed framework is relevant to integrated modelling of hydrology and human impacts and therefore fits into the concepts of "Panta Rhei", the scientific decade 2013-2022 promoted by the International Association of Hydrological Sciences.