Hydrological model of Amur River basin: development and application for flood risk management
The first regional process-oriented model of runoff generation for the whole Amur River basin has been developed. The model is based on the ECOMAG modelling system and describes processes of snow accumulation and melt, soil freezing and thawing, water infiltration into unfrozen and frozen soil, evapotranspiration, thermal and water regime of soil, overland and subsurface flow. To simulate channel flow a hydrodynamic MIKE-11 model has been coupled with the ECOMAG. The model has been calibrated using streamflow discharges measured in 15 different gauges of the main river and its tributaries for 10 years (1994-2003). Validation of the model has been carried out for next 10-year period (2004-2013). On the basis of the numerical experiments, opportunities of the model were illustrated by the example of the assessing the flood control function of the existing and projected reservoirs on the Zeya and Bureya rivers. It has been shown, particularly, that the absence of the Zeya and Bureya reservoirs would have resulted in a rise of water level in the Middle Amur by 1.7–2.1 m during flood wave rise and by 0.4–0.5 m during flood peak. In this case, the duration of water level standing above flooding level could increase 2–3 times. Thus, in the absence of the Zeya and Bureya reservoirs, the after effects of the flood of 2013 in the basin of the Middle Amur could have been much more disastrous, and the damage could have been more catastrophic. In addition, hydrological consequences of climate change in the Amur basin, including climate impact on hydrological extremes, have been assessed on the basis of numerical experiments with regional hydrological and ensemble of global climate models. It has been shown that the projected hydrological changes are insignificant in comparison with the uncertainty noise.