Liu Changming

Impact of land-cover and climate changes on runoff of the source regions of the Yellow River

After dividing the source regions of the Yellow River into 38 sub-basins, the paper made use of the SWAT model to simulate streamflow with validation and calibration of the observed yearly and monthly runoff data from the Tangnag hydrological station, and simulation results are satisfactory. Five land-cover scenario models and 24 sets of temperature and precipitation combinations were established to simulate annual runoff and runoff depth under different scenarios. The simulation shows that with the increasing of vegetation coverage annual runoff increases and evapotranspiration decreases in the basin. When temperature decreases by 2°C and precipitation increases by 20%, catchment runoff will increase by 39.69%, which is the largest situation among all scenarios.

Environmental flow requirements of fish in the lower reach of the Yellow River

A holistic approach using multiple modules is used to recommend the environmental flow for fish in the lower Yellow River. The basic steps are as follows: (1) acquire the flow-related information on selected fish in the lower Yellow River, including fish species composition, abundance and habitat use in relation to flow conditions; (2) link the selected fish to key aspects of the flow regime using a conceptual model; (3) identify the environmental flow objectives; and (4) use hydraulic and hydrologic models to determine the magnitude, duration, frequency and timing of flows required to meet these objectives.

Changes of runoff components in the source region of the Yellow River during the second half of the twentieth century

In the 1990s, the runoff volume at Tangnaihai hydrologic station decreased remarkably. The runoff components were separated and climate influences on it were analysed. Researches show that in summers, the decrease in stream flow was mainly caused by the decrease in direct flow, while during fall seasons it resulted from decrease in both base flow and direct flow. For the whole Yellow River study source region, change in precipitation both spatially and temporally was the main contributor to the decrease in runoff and its components.

Natural eco-environmental evaluation of eastern Qinghai-Tibet Plateau using RS and GIS

The impact of interbasin water transfer on environment is very significant. The affected area of the west route scheme of the South to North Water Transfer Project in China (SNWT) is located in the eastern Tibetan Plateau, where the altitude is high with frigid eco-environment. In this article, remote sensing and GIS are applied to analyze the natural environment and the natural environment index is established to express the natural conditions of the study area. After the natural environment index is divided into four grades and the features of each grade are analysed, some results are obtained for reference in environmental assessment of the west route of SNWT.

Assessment and utilization of soil water resources

Based on the analyses of water interactions and water balance, this paper discusses the issues on the assessment and regulation of soil water resources, which lays the scientific basis for limited irrigation and water-saving agriculture.