S6

Understanding the human footprint on the hydrological cycle/processes in a changing world
Convener: David Hannah | Co-Conveners: Gil Mahé, Guillaume Thirel, Honeyeh Iravani, Anil Mishra

Human impacts on the water cycle are ever increasing. Some of our actions affect purposefully water stores and fluxes, while other human activities have unintended impacts on catchment. In the Anthropocene, humans have reshaped the water cycle and altered hydrological processes in three connected ways: (1) every agricultural, industrial, and domestic activity uses water directly and indirectly, (2) humans have directly modified 77% of the Earth's land surface, excluding Antarctica, through activities such as agriculture, deforestation, and wetland destruction, and (3) climate change is altering nearly every water store and flux (shrinking glaciers, permafrost melting, depleted groundwater, precipitation timing and intensity, drought, flooding, evapotranspiration etc.). These human modifications are creating a ‘water crisis’ not only by modifying water quantity (i.e. availability) dynamics but also water quality (i.e. pollution). In response to this crisis, we call on researchers to more explicitly conceptualise, quantify and understand the human footprint on the hydrological cycle/ processes, and implications for the sustainable management of freshwaters. In addition, nine years after the ‘Testing simulation and forecasting models in non-stationary conditions’ workshop at the 2013 IAHS general assembly, we urge researchers to present their most recent advances on preparing hydrological models to face a changing future. Recent advances on model robustness, associated testing, multi-modelling, understanding and reducing uncertainties are welcome. All spatial and temporal scales are concerned, as well as highly modified to pristine catchment (engineered, urban, rural and near-natural).