Transparent Modelling in Interdisciplinary Research: An Illustration from an Agro-Hydrological Study in the Cambodian Mekong Delta

Ensuring transparency and a clear communication of uncertainties poses a ubiquitous challenge in hydrological modelling, both in the application of existing models in new domains and in the development of new models. This challenge becomes especially pressing in interdisciplinary research contexts, where expectations of models and understanding of their roles often differ. While an increasing body of work on good modelling practices in hydrology has been developed over the past years, there is no common standard yet that could help modellers address these challenges. In particular, one aspect that is rarely explicitly described in modelling studies is the effect of preliminary perspectives of different members of the modelling team and subjective choices along the modelling chain on the model’s outputs and uncertainties. 

This study takes the example of an agro-hydrological model developed in the Cambodian Mekong Delta (Southeast Asia) to explore this social side of model development and application in an international, interdisciplinary development context. The model in question was developed to explore how regional hydrological dynamics - and particularly water availability for agriculture - would change following hydro-infrastructure rehabilitation projects funded by international development agencies. The implementation of these projects can be seen against the background of the shifting hydrological dynamics in the Mekong basin, driven by climate change, hydropower construction, and land use changes. In its final version, the model allows for a relative assessment of the effects of water availability for irrigation on the agricultural productivity in the study area, taking into account different configurations of the artificial channels to be rehabilitated as well as the annual Monsoon inundations and the hydrological dynamics of the Mekong’s deltaic distributaries. 

In our case study, we strive to highlight the impact of the expectations and goals of different members of the modelling team, originating from different disciplines, as well as the subjective modelling choices and simplifications made collectively throughout the modelling process, on the final results. In particular, we also examine the process by which simplifications were implemented and the perceptual model was negotiated, against the background of the data scarcity that is characteristic of many hydrological studies carried out in the Global South. Furthermore, we reflect on how existing guidelines for good modelling practices (such as FAIR principles) have helped with the communication of uncertainties and limitations of the model, and how future guidelines could evolve to better take into account and transparently represent social dynamics within interdisciplinary modelling teams, for instance through the use of positionality statements.