Fan Jian-rong

Assessment and spatial distribution of sensitivity of soil erosion in Tibet

Based on Universal Soil Loss Equation and methods of mathematics model and GIS analysis, this study classified influence of precipitation, soil, topography and vegetation upon sensitivity of soil erosion into five different degrees which are extreme sensitivity, quite sensitivity, sensitivity, less sensitivity and no sensitivity. Assessment map of each factor was generated separately. Integrated assessment map of sensitivity of soil erosion has also been drawn by overlapping function with Arcinfo. Furthermore, the study analyzed distribution characteristics and spatial difference of sensitivity of soil erosion under special plateau environment of Tibet. According to sensitivity degree, some important controlling regions was confirmed so that departments of water conservancy, traffic management and agriculture could make scientific and reasonable decisions for their respective subject planning.Based on Universal Soil Loss Equation and methods of mathematics model and GIS analysis, this study classified influence of precipitation, soil, topography and vegetation upon sensitivity of soil erosion into five different degrees which are extreme sensitivity, quite sensitivity, sensitivity, less sensitivity and no sensitivity. Assessment map of each factor was generated separately. Integrated assessment map of sensitivity of soil erosion has also been drawn by overlapping function with Arcinfo. Furthermore, the study analyzed distribution characteristics and spatial difference of sensitivity of soil erosion under special plateau environment of Tibet. According to sensitivity degree, some important controlling regions was confirmed so that departments of water conservancy, traffic management and agriculture could make scientific and reasonable decisions for their respective subject planning.

Outburst risk of barrier lakes in Sichuan, China

Abstract34 barrier lakes induced by earthquake have been formed by wedged debris on the river channels after a massive earthquake happening on May 12 in Sichuan, China. Among them, the Tangjiashan Barrier Lake is the largest one. It faces very urgent risk of dam breaking when water level reaches the top and begins overflow in case of storm rainfalls and continually aftershocks, threatening already devastated cities and villages with about 1.5 million people downstream. The outburst of a similar barrier lake occurred in the Minjiang River in 1933, causing a catastrophic flood. Risk analysis indicates that not all barrier lakes are highly dangerous. Only those lakes with very high dams and water to be filled up in short period need to be dealt with immediately.

Empirical-Statistical Models Based on Remote Sensing for Estimating the Volume of Landslides Induced by the Wenchuan Earthquake

The Wenchuan Ms 8.0 earthquake on May 12, 2008 induced a huge number of landslides. The distribution and volume of the landslides are very important for assessing risks and understanding the landslide — debris flow — barrier lake — bursts flood disaster chain. The number and the area of landslides in a wide region can be easily obtained by remote sensing technique, while the volume is relatively difficult to obtain because it requires some detailed geometric information of slope failure surface and sub-surface. Different empirical models for estimating landslide volume were discussed based on the data of 107 landslides in the earthquake-stricken area. The volume data of these landslides were collected by field survey. Their areas were obtained by interpreting remote sensing images while their apparent friction coefficients and height were extracted from the images unifying DEM (digital elevation model). By analyzing the relationships between the volume and the area, apparent friction coefficients, and the height, two models were established, one for the adaptation of a magnitude scale landslide events in a wide range of region, another for the adaptation in a small scope. The correlation coefficients (R2) are 0.7977 and 0.8913, respectively. The results estimated by the two models agree well with the measurement data.

Study on the Restoration of Vegetation in Arid-Hot Valleys Along the Jinshajiang River

Based on the features of environment and the fact of successful artificial afforestation, the paper points out that the restoration of vegetation in Arid-hot valleys along the Jinshajiang River should be implemented mainly by planting sparse - arbor/ shrub/ tussock Combination. Four ways to restore vegetation in the area are given in the paper.

Floristic Characteristics of the Rare and Endangered Plants and the Conservation Countermeasures in Tibet, China

The floristic elements and the geographical distribution are analyzed in this paper based on statistics of elements of rare and endangered plants in Tibet. The results have been gained as following: ① According to “the National Important Wild Conservative Plants List (List 1)” and “the National Important Wild Conservative Plants List (List 1)”, there are a total of 54 plant species (48 genera and 33 families); ② The geographical elements are very complicated in Tibet with 12 of 15 distribution patterns of geenra classified by academician Wu; ③ There are obvious temperate genera with 28 genera accounting for 60.4% of the total genera: ④ There are abundant endemic species accounting for 18.52% of total species but poor endemic genera; ⑤ The geographical distribution is uneven and a great of species distribute in the areas between 1 000 m and 3 500 m above sea level; ⑥ To protect the rare and endangered plants efficiently, six conservation measures are proposed, and 35 species are suggested for the conservative plants of the autonomous conservation level.

Effect of Socio-economic Factors on Soil Erosion: A Literature Review

Based on the summarization of the research on man-made accelerated erosion,this paper introduced the four social-economic factors which affect soil erosion including population growth,policy,economic development and land use changes,and reviewed the research methods for the social-economic factors affecting soil erosion both at home and abroad.After that,it is proposed that three aspects of the research need further study: interdisciplinary studies,social-economic models and regional differences.

Evaluation on the essentiality grades of water conserving in Tibet, China

Taking Tibet as an example, the functional essentiality degrees of water resources conserving of regions were discussed in this paper. At first, based on the status of regional vegetation, whether the region has the function of water conserving was made certain. And then, according to the impacted objects of water resources conserving, taking into account the demands for water and regional supply capacities of water and the requirement of environmental protection, the functional grades of regional water resources conserving of Tibet were evaluated in this paper.