Challenge for the development of a calibration-free physically-based rainfall-runoff model

Abstract

The conventional wisdom in hydrology suggests that rainfall-runoff models require calibration due to the presence of parameters. However, could it be possible to challenge this notion? Is it feasible to deduce a physically-based runoff model with high precision based on measuring or estimating hydrological signatures such as soil, geology, vegetation, and terrain? In this session, we will discuss the academic challenges worth pursuing towards hydrology in 2050. The author has been engaged in understanding rainfall-runoff processes and developing/applying physically-based models since around 2000. This began with the Prediction in Ungauged Basins (PUB) initiative by IAHS (2003-2012). Predicting hydrology in ungauged basins remains a timeless and universal theme. This paper reviews the main topics discussed in the PUB initiative, presents progress to date, and outlines future toward a calibration-free rainfall-runoff model.