Elements of a flexible approach for conceptual hydrological modeling: 1. Motivation and theoretical development

TLDR

The flexible framework lets hydrologists hypothesize, build, and test diverse model structures with generic components, addressing catchment‑scale challenges of limited process understanding and data. This paper introduces the framework to generalize and systematize conceptual hydrological models and provide a robust platform for understanding and modeling hydrological systems. The authors formulate a modular architecture that represents storage, release, and transmission processes and present numerical strategies for implementing the equations within a computationally robust system. In a companion study, the framework is shown to enable more systematic hypothesis testing, better characterization of catchment diversity, and progress toward unified catchment‑scale hydrological theory.

Abstract

This paper introduces a flexible framework for conceptual hydrological modeling, with two related objectives: (1) generalize and systematize the currently fragmented field of conceptual models and (2) provide a robust platform for understanding and modeling hydrological systems. In contrast to currently dominant “fixed” model applications, the flexible framework proposed here allows the hydrologist to hypothesize, build, and test different model structures using combinations of generic components. This is particularly useful for conceptual modeling at the catchment scale, where limitations in process understanding and data availability remain major research and operational challenges. The formulation of the model architecture and individual components to represent distinct aspects of catchment‐scale function, such as storage, release, and transmission of water, is discussed. Several numerical strategies for implementing the model equations within a computationally robust framework are also presented. In the companion paper, the potential of the flexible framework is examined with respect to supporting more systematic and stringent hypothesis testing, for characterizing catchment diversity, and, more generally, for aiding progress toward more unified hydrological theory at the catchment scale.