Numerical Modelling of Ice Floods in the Ning-meng Reach of the Yellow River Basin

The Ning-Meng reach of the Yellow River basin is located in the Inner Mongolia region at the Northern part of the Yellow River. Due to the special geographical conditions, the river flow direction is towards the North causing the Ning-Meng reach to freeze up every year in wintertime. Both during the freeze-up and break-up period, unfavourable conditions occur which may cause ice jamming and ice dam formation leading to dike breaching and overtopping of the embankment. Throughout history this has often led to considerable casualties and property loss. Enhanced economic development and human activities in the region have altered the characteristics of the ice regime in recent decades, leading to several ice disasters during freezing or breaking-up periods. The integrated water resources management plan developed by the Yellow River Conservancy Commission (YRCC) outlines the requirements for water regulation in the upper Yellow River during ice flood periods. YRCC is developing measures that not only safeguard against ice floods, but also assure the availability of adequate water resources. These provide the overall requirements for developing an ice regime forecasting system including lead-time prediction and required accuracy. In order to develop such a system, numerical modelling of ice floods is an essential component of current research at the YRCC, together with field observations and laboratory experiments. In order to properly model river ice processes it is necessary to adjust the hydrodynamic equations to account for thermodynamic effects. In this research, hydrological and meteorological data from 1950 to 2010 were used to analyse the characteristics of ice regimes in the past. Also, additional field observations were carried out for ice flood model calibration and validation. By combining meteorological forecasting models with statistical models, a medium to short range air temperature forecasting model for the Ning-Meng reach was established. These results were used to improve ice formation modelling and prolong lead-time prediction. The numerical ice flood model developed in this thesis for the Ning-Meng reach allows better forecasting of the ice regime and improved decision support for upstream reservoir regulation and taking appropriate measures for disaster risk reduction.

Wang Chunqing was born in 1972 in the historic city Kaifeng of Henan Province, China. He obtained his bachelor’s degree in Department of Atmospheric Science of Nanjing University from 1990-1994. After graduation, he has worked at the Hydrology Bureau of the Yellow River Conservancy Commission, part of the Ministry of Water Resources (MWR), and has been engaged in the meteorological information processing and weather forecast of the Yellow River basin. From 2001-2003, he took part in the Water Scarcity Training Group sponsored by MWR and the Dutch government, and obtained MSc degree of Hydroinformatics (HI) at UNESCO-IHE. In 2009, he started the (partly time) PhD study at UNESCO-IHE with a main focus on the ice regime and ice flood modeling for the Ning-Meng reach of the Yellow River. Chunqing is currently director of the Hydrological and Water Resources Information Center of Hydrology Bureau, chiefly responsible for meteorological forecasting, water resources and ice flood forecasting, and network management of the Hydrology Bureau.