On the application of dynamical measures of hydrologic response to prediction and similarity assessment in watersheds

Abstract

The Prediction in Ungauged Basins (PUB) initiative set out to improve the understanding of hydrological processes with an aim of improving hydrologic models for application in ungauged basins. With a majority of basins around the world essentially ungauged, this suggests the need to shift from calibration-based models that rely on observed streamflow data to models based on process understanding. This is especially important in natural infrastructure planning projects such as investments in the conservation of wetlands across the watershed, where the lack of streamflow data hinders the quantification of their benefits (such as flood attenuation), resulting in a difficulty in prioritization. This research sought to contribute to this growing body of literature by (a) developing visual tools and metrics for assessing flow dynamics and flood attenuation benefits of wetlands in relation to their position in the watershed, (b) examining distribution-based topographic metrics in regard to their efficacy in predicting hydrologic response and providing a methodology for examining other metrics in future studies, (c) building robust functional forms for two important catchment metrics: the width function and hypsometric curve, and (d) devising a hierarchical clustering approach to assess hydrological similarity and find analogous basins that is computationally efficient and has a potential for large-scale applications. Taken together, this study paves the way toward an analytical formulation of the geomorphological instantaneous unit hydrograph (GIUH) that can be used to assess the hydrological behavior in ungauged or data-scarce basins