High and low flows and associated floods and droughts are extreme hydrological phenomena caused by meteorological anomalies and modified by various catchment processes and human activities. The scope of this general session on hydrological extremes is to learn from the similarities and differences of basic ideas and concepts for both extremes, from generating physical processes and feedbacks to monitoring and modelling approaches.

The main objectives of this session are:
- to foster the understanding of the main governing processes of hydrological extremes, including spatial and temporal patterns of floods and droughts,
- to discuss modelling approaches and concepts on how to include process understanding in predictive models of floods and droughts,
- to present methods and practical applications for i) flood and drought monitoring, detection (including suitable indices) and mapping, ii) estimating flood and drought frequency, spatial patterns and short-term and long-term variability, and iii) predicting hydrological extremes in near real-time and in the far future, from catchment to regional and continental scales,
- to discuss regionalisation methods for predicting hydrological extremes in ungauged catchments,
- to address the potential impacts of global change, including climate and land use changes, on hydrological extremes,
- to discuss the human aspects of flood and drought at various scales, focussing on impacts of hydrological extremes on society and influence of society on hydrological extremes, including feedbacks between climate, society and hydrology, and
- to profit from the similarity and differences of process understanding and monitoring and modelling concepts for both extremes.

The scope of the session includes both general methodological contributions and case studies of hydrological extremes in different regions covering a wide range of spatial scales. All methodological contributions will ideally discuss the benefits of the method for the challenges of both hydrological extremes.

Our keynote speakers for 2017 are Christel Prudhomme (CEH), Sergiy Vorogushyn (GFZ), Eric Wood (Princeton), Stacey Archfield (USGS) and Luis Samaniego (UFZ). The excellent submission of Ted Veldkamp (VU) has been classified as solicited talk, as a "label of excellence".

This session is jointly organised by the Panta Rhei Working Groups “Understanding Flood Changes”, “Changes in Flood Risk”, and “Drought in the Anthropocene” and will further stimulate scientific discussion on flood change detection and attribution and the feedbacks between drought and society. The session is linked to the European Low Flow and Drought Group of UNESCO´s IHP-VIII FRIEND-Water Program, which aims to promote international drought research.