Hydrological design in the HELPING decade – inspiring the community to innovate the hydrological design concept

Hydrological design, which ultimately leads to the dimensioning of hydrostructures for e.g. flood protection or water supply, is a key task of hydrologists and most important for the majority of stakeholders, authorities and practitioners. Hydrological design, therefore, must be communicated to the interested parties in an appropriate and comprehensive way. In this work, by collecting the most critical gaps and challenges associated with hydrological design, we aim to stimulate and serve as a basis for the work of the working group (WG) Hydrologic Design: Solutions and Communication within the International Association of Hydrological Sciences (IAHS) HELPING decade. Aside from the developments in the last few decades, there are still major challenges and knowledge gaps associated with hydrological design, such as data limitations, e.g. missing or incomplete data, uncertainty related to model choice and evaluation, and a lack of efficient communication between science and practice. We invite the community to join us in innovating the hydrological design concept.