The 2023 Ralph Alger Bagnold Medal is awarded to Dimitri Lague for impactful research in quantifying landscapes and their dynamics through a suite of innovative approaches, including new technologies and techniques, alongside outstanding leadership in open science.
Dimitri Lague is an international leader in the field of geomorphology. He is recognised as a deep thinking, quantitative geomorphologist who is making fundamental contributions to the discipline. His work ranges from advancing understanding on the central role of the stochastic distribution of floods in landscape evolution through to exploration of the intricate coupling between physical and biological processes in salt marshes, as well as advancing novel methods and techniques that unlock substantive advances.
His contributions have significantly moved the field forward, establishing a new level of rigour and robust platforms on which others can work with confidence. The representation of erosion processes is a central element of many surface process and landscape evolution models. After initial models had used simple, but seemingly effective numerical descriptions of erosion, Dimitri was instrumental in exploring its many complexities and identifying essential components of a full erosion model. These include the roles of bedload and suspended load, lateral as well as vertical channel dynamics, transport and erosion thresholds, and the importance of discharge variability. Dimitri’s pathfinding, painstaking and profoundly thorough approach culminated in a single-authored review paper, published in 2014, which is now a part of the canon of Geomorphology.
Additional to this seminal work, Dimitri has been working on the digitalisation of landforms throughout his career. Initially, his efforts focused on the scanning of the topographies of lab experiments, in order to allow their systematic characterisation and comparison with other experiments and actual landforms. With the advent of longer-range scanners, Dimitri has migrated to detailed digitalisation and change detection in real landscapes. Being aware of the many pitfalls of this approach, he has made a major effort to determine the capabilities and limitations of scanning and change detection. This work is foundational and now forms the sound basis for an ever-expanding number of studies exploiting scanner technology, which have become a mainstay of modern process geomorphology. His commitment to making these analytical tools open and available to the whole community has been a notable commitment and contribution to the discipline.
Dimitri excels in sustained, focused work, pursuing meaningful progress, rather than publishable units. His most influential work is comprehensive, even expansive, based on long-time investments. It has a strong added value because of these attributes. Dimitri communicates his findings in elegantly crafted papers, as well as richly illustrated presentations, replete with humour.
For these reasons and, it is certain, several others, Dimitri Lague will be a very deserving recipient of the EGU’s Ralph Alger Bagnold Medal.