PUB Working Group 4-3 (WG4-3): Establishment of a Guideline for Selecting Hydrologic Models through Development of Uncertainty Evaluation Indices

(This is component 2 of SAKE (Suimon Adventure for Knowledge Evolution))

Objectives:

• Development of new uncertainty evaluation methods and indices

• Establishment of a guideline for selecting hydrologic models using new uncertainty evaluation methods and indices

In Japan, many physically based distributed hydrological models have been developed and applied to many watershed basins, while the storage function model, a simple lumped conceptual model are still widely used for actual watershed planning. This is because

• the indices to show the model performance and/or uncertainty are not well defined
• the methods to assess model performances and/or uncertainty are not clear, and thus
• the performances of newly developed models are not well assessed.

In association with watershed properties, data availability and the purpose of model use, a suitable hydrologic model will be different in model structure, distributed or lumped, and so on.

In this study, uncertainty evaluation methods and indices to show the model performance and uncertainty are newly devised to assess the uncertainty derived from forcing data, model structure and model parameter identifications. Through the newly developed indices, existing lumped and distributed models are assessed in their forecasting performance and uncertainty, and in what environment what kind of model shows higher performance than other models is clarified. Finally, a guide line to recommend which model should be applied in ungauged basins will be established.

Key Participants:

• Akira Kawamura, School of Urban Environmental Sciences, Tokyo Metropolitan University