Please note that this session was withdrawn and is no longer available in the respective programme. This withdrawal might have been the result of a merge with another session.


Pathways towards solving the Unsolved Problems in Hydrology (UPH)

The International Association of Hydrological Sciences (IAHS), in collaboration with the Hydrology Divisions of EGU and AGU as well as the IAH, launched in 2017 a public consultation process for compiling a list of unsolved scientific problems in hydrology which resulted, in 2019, in a set of 23 Unsolved Problems in Hydrology (UPH) (see

The UPH are articulated around 7 themes: Time variability and change, Space variability and scaling, Variability of extremes, Interfaces in hydrology, Measurements and data, Modelling methods, and Interfaces with society. Some of the UPH may have already been partially studied. Recent research may shed light on how to move forward in a more holistic way. A crucial issue is to put together fragmented knowledge to address the questions raised and enhance coherence in hydrological sciences.

The purpose of this session is to discuss progress in any of the 23 UPH. Contributions are encouraged to either:
- present research results that advance the understanding of any of the 23 UPH,
- review (or present a contribution to review) the state of the art of one (or more) of the UPH, pointing towards directions where progress is most promising.

Authors are asked to clearly state the UPH their work refers to or could contribute to solve. The authors may also reflect on how the community could evaluate if an UPH can be considered solved or not.

Co-sponsored by IAHS
Convener: Elena Toth | Co-conveners: Berit Arheimer, Günter Blöschl, Christophe Cudennec, Maria-Helena Ramos