Parameter estimation for precipitation-runoff models

Precipitation-runoff models are established tools in hydrology and are used for river forecasting and flood prediction, water resources management, and climate change impact studies. Nowadays there is a focus on spatially distributed predictions, including sites without measurements, thus fostering the need for spatially distributed precipitation-runoff models. The use of distributed models enables a more realistic representation of the heterogeneity found in precipitation and watershed characteristics. However, the shift from the (traditional) lumped to distributed hydrological modelling significantly increases the complexity of the parameter estimation problem. The topic of parameter estimation is also closely related to the field prediction in ungauged basins (PUB), where no runoff data are available for the calibration of model parameters. The unifying theme of this research proposal is the focus on the distributed estimation of model parameters in both gauged and ungauged catchments. The objective is to reduce the uncertainty in the simulation results and to increase the predictive capability of distributed precipitation-runoff models. This will be achieved by five tasks: [1] Parameterization of an existing conceptual modelling framework for improved distributed modelling; [2] Analysis of the effect of the spatial discretization on the parameter values; [3] Distributed a priori parameter estimation from spatial data sets; [4] Global optimization of distributed parameters; [5] Prediction in ungauged or poorly gauged basins. It is expected that task [2] will yield implications for the tasks [3] to [5]. A combination of existing methods will be tested and, where necessary, novel methods will be developed. The methods will be applied in several Austrian and US meso-scale catchments (30 or more), which will represent a wide range of climatological and watershed characteristics, including low-land and alpine catchments in humid to semi-arid environments. The research of this proposal will be conducted at one of the world`s leading institutions in this research area. This offers the opportunity to infuse and refine novel scientific advances in an Austrian context. The research will specifically increase our capability for streamflow forecasting and flood prediction, and, additionally, will also contribute to water resources and climate change impact assessment.