Reductions in non-point source pollution through different management practices for an agricultural watershed in the Three Gorges Reservoir Area

Non-point source water pollution generated by agricultural production is considered a major environmental issue in the Three Gorges Reservoir Area （TGRA） of China. The Annualised Agricultural Non-Point Source Pollution （AnnAGNPS） model was selected to assess the impact of the application of various management treats, including seven crops, five fertilizer levels and three-group management practice scenarios, on water quality from Heigou River Watershed in TGRA. The scenario subsets include conservation tillage practice （CTP）, conservation reserve program （CRP） and conversion of cropland into forestland program （CCFP）. Results indicated that tea can not be replaced by other crops because comparatively tea resulted in a higher sediment yield. CTP with no-tillage was more effective to reduce sediment yield, but could increased nutrient loss. CRP reduced sediment yield significantly, but slightly benefited on nutrient loss. CCFP reduced not only sediment yield but also the nutrient loss significantly. The conversion of cropland with a slope greater than 10° into forestland was found to be the best scenario as the sediment yield export is less than 5 tons/ha and nutrient loss is within the permissible limit.

Landslides and Slope Aspect in the Three Gorges Reservoir Area Based on GIS and Information Value Model

Slope aspect is one of the indispensable internal factors besides lithology, relative elevation and slope degree. In this paper authors use information value model with Geo graphical Information System （GIS） technology to study how slope aspect contributes to landslide growth from Yunyang to Wushan segment in the Three Gorges Reservoir area, and the relationship between aspect and landslide growth is quantified. Through the research on 205 landslides examples, it is found that the slope contributes most whose aspect is towards south,southeast and southwest aspect contribute moderately, and other five aspects contribute little. The research result inosculates preferably with the fact. The result of this paper can provide potent gist to the construction of Three Gorges Reservoir area in future.

Surface Microtextures of Slipping Zone Soil of Some Landslides in the Three Gorges Reservoir District and Their Significance

The mineral assemblage and content and surface microtextures of slipping zone soil of several landslides in the Three Gorges Reservoir District have been analyzed using the scanning electron microscope (SEM) and X-ray diffractometer (XRD). All the mineral assemblages are similar in these landslides. The main minerals are montmorillonite, illite, kaolinite, chlorite, quartz and feldspar. There are two kinds of surface microtexture in the slipping zone soil, i.e., linear scratches and arcuate scratches. Based on analyses of the changes of the microtextures, one can obtain information about the number, directions and stages of landslide movements. The authors have also studied the mechanism of landslide formation, evaluated the stability of landslides and revival possibility of ancient landslides and forecasted the activity of similar landslides in different districts. The surface microtexture features of stable landslides and mobile landslides are summarized and it is concluded that the existence of filamentous bacteria may result in or increase movements of landslides.

Land Use of the Three Gorges Reservoir Area and the Effect on Its Landscape Pattern in the Recent 50 Years

The paper makes detailed analysis on the changing processes of the main types of land use in Three Gorges Reservoir Area through the techniques of RS （Remote Sense） and GIS （Geography Information System）. Based on the theory of landscape ecology, many types of landscape pattern indexes are calculated and made correlation analysis. The results indicate that： in 1995 the ecological environment of Three Gorges Reservoir Area was the most vulnerable in the recent 50 years, but resumed in 2002; the landscape pattern diversity index, fractal dimension index and fragmentation index has close correlation with the area of land use/cover change （LUCC）. The research also releases that the increase of the cultivated land, grassland and construction land deteriorates the landscape ecological pattern, while the increase of forest land area will help restore the landscape ecological pattern to its original state. The rapid change of grassland is an important index of the change of landscape pattern, because it has the most effect on change of landscape pattern index.

Centrifugal model test on a riverine landslide in the Three Gorges Reservoir induced by rainfall and water level fluctuation

Frequent soil landslide events are recorded in the Three Gorges Reservoir area,China,making it necessary to investigate the failure mode of such riverside landslides.Geotechnical centrifugal test is considered to be the most realistic laboratory model,which can reconstruct the required geo-stress.In this study,the Liangshuijing landslide in the Three Gorgers Reservoir area is selected for a scaled centrifugal model experiment,and a water pump system is employed to retain the rainfall condition.Using the techniques of digital photography and pore water pressure transducers,water level fluctuation is controlled,and multi-physical data are thus obtained,including the pore water pressure,earth pressure,surface displacement and deep displacement.The analysis results indicate that:Three stages were set in the test(waterflooding stage,rainfall stage and drainage stage).Seven transverse cracks with wide of 1–5 mm appeared during the model test,of which 3 cracks at the toe landslide were caused by reservoir water fluctuation,and the cracks at the middle and rear part were caused by rainfall.During rainfall process,the maximum displacement of landslide model reaches 3 cm.And the maximum deformation of the model exceeds 12 cm at the drainage stage.The failure process of the slope model can be divided into four stages:microcracks appearance and propagation stage,thrust-type failure stage,retrogressive failure stage,and holistic failure stage.When the thrust-type zone caused by rainfall was connected or even overlapped with the retrogressive failure zone caused by the drainage,the landslide would start,which displayed a typical composite failure pattern.The failure mode and deformation mechanism under the coupling actions of water level fluctuation and rainfall are revealed in the model test,which could appropriately guide for the analysis and evaluation of riverside landslides.

Provenance of Detrital Magnetites from Quaternary Sediments in the Yichang Area and its Significance to the Birth of the Three Gorges, Yangtze River

Objective In recent years, the birth time and evolution of the Three Gorges, Yangtze River has become a focused topic. Different from previous studies, this study used provenance analysis of Quaternary sediments to discuss this question. Among those minerals in Quaternary sediments, magnetite was rarely studied. This paper presents element geochemistry and backscatter images of detrital magnetites from the Quaternary sediments in the Yichang area of Hubei Province. By discussing the provenance changes of detratic magnetites, we suggested the birth time of the Three Gorges of the Yangtze River.

Gravity inversion of deep-crust and mantle interfaces in the Three Gorges area

To better understand the heterogeneity of deep-crust and mantle interfaces in the region of the Three Gorges, China, we used the Parker-Oldenburg iterative inversion method to invert existing Bouguer gravity data from the Three Gorges area （ 1 ： 500000） , a new gravity map of the Three Gorges Dam （ 1 ： 200000） , and the results of deep seismic soundings. The inversion results show a Moho depth of 42 km be- tween Badong and Zigui and the depth of the B2 lower-crustal interface beneath the Jianghan Plain and sur- rounding areas at 21 -25 km. The morphology of crustal interfaces and the surface geology present an over- pass structure. The mid-crust beneath the Three Gorges Dam is approximately 9 km thick, which is the thin- nest in the Three Gorges area and may be related to the shallow low-density body near the Huangling anti- cline. The upper crust is seismogenic, and there is a close relationship between seismicity and the deep- crust and mantle interfaces. For example, the MS. 1 Zigui earthquake occurred where the gradients of the Moho and the B2 interface are the steepest, showing that deep structure has a very important effect on re- gional seismicity.

Impact of the Small Town Construction on Original Inhabitants in the Three Gorges Reservoir Area——A Case Study in Lishu Village, Changling Town, Chongqing Municipality, China

Based on the five-year long dynamic tracking and investigation of the peasant households of the Lishu village, the influences by small town construction on the economy and employment of the original peasant households are discussed. On the one hand, small town construction plays a positive role in adjustment of the industrial structure of the original peasant households and in the transfer of their employment towards non-agricultural industries. On the other hand the economic growth of the original peasant households is not so well sustainable, and is so fluctuating. Moreover, the unbalance of income distribution of the said households has been furthered, and small town construction has made the existing labor surplus of the original peasant households more serious, particularly the women labor surplus.

Application of Vegetation Geosynthetic Technique to Slope Stability in the Three Gorges Reservoir

The vegetation geosynthetic reinforced slope is one of the new composite structures in civil engineering. It has a series of characteristics, such as low cost, convenient construction, optimal land utilization and flexible structure, and it has been widely used in hydraulic engineering, road, railway and harbor construction. The Three Gorges reservoir bank protection system is a challenging work. As the background, the interaction mechanism of soil and reinforced material has been studied. The test engineering is simulated by the numerical methods. The failure mechanism of the reinforced slope in the process is studied through analyzing the variation of the displacement, stress, plastic failure fields and factor of safety in the changing process of the water level. The reasonable evaluation of the protecting effect and bank slope stability is carried out. The research results could be used in the protective design and construction in the high slope in the Three Gorges reservoir region, and it also could provide reference to other protective engineerings in the littoral area.

The Three Gorges Project and Its Environmetal Impact

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Application of Auto-regressive Linear Model in Understanding the Effect of Climate on Malaria Vectors Dynamics in the Three Gorges Reservoir

It is important to understand the dynamics of malaria vectors in implementing malaria control strategies. Six villages were selected from different sections in the Three Gorges Reservoir fc,r exploring the relationship between the climatic ｜：actors and its malaria vector density from 1997 to 2007 using the auto-regressive linear model regressi^n method. The result indicated that both temperature and precipitation were better modeled as quadratic rather than linearly related to the density of Anopheles sinensis.

Yichang City—The place where both the Three Gorges and Gezhouba projects are being constructed

Yichang City is the place where both the Three Gorges and the Gezhouba Dam projects are being constructed. Practice shows that any large State planned project will bring prosperity to the local economy. The Gezhouba Dam Project in Yichang has provided the first opportunity for the city’s development During the first stage of the Gezhouba project from 1971 to 1980, the annual average progressive growth rate of fixed assets investment and

APPLICATIONS OF REMOTE SENSING IN ENVIRONMENTAL INVESTIGATION AND CHANGE ANALYSIS IN THE THREE GORGES AREA

1. INTRODUCTION The proposed Three Gorges Project, one of the biggest hydroelectric projects in the world, will dam the middle reaches of the Changjiang (Yangtze) River, the third longest river in the world, and form a large reservoir. Its impacts on environment have attracted wide attention. Entrusted by National Scientific-Technical Commission, the Chinese Academy of Sciences (CAS) was in charge of a research project on this issuse from 1984 to 1989. Tho use of remote sensing played an important role in the project considering the study area is mountainous and not convenientlv located, which makes it difficult to conduct the research onlv using conventional means.

Building the Three Gorges Project for the Chinese Nation—An Interview with General Manager Lu Youmei, China Yangtze River Three Gorges Project Development Corporation

The Yangtze River has nurtured the fertile land on both its banks and hundreds of millions of Chinese people. but its raging waters have also wreaked havoc on the people living in its reaches. Since the founding of New China, large-scale surveys, planning, scientific research and feasibility studies have been carried out in an effort to harness the

Yiling District,Pearl of the Three Gorges Area

YLING District of Yichang City, Hubei Province, near the Yangtze liver Xiling Gorge, marks the midway spot between the river’s upper and middle reaches. It is site of the Gezhouba Dam and the Three Gorges Project dam, and has consequently been dubbed gate to the Three Gorges. With a territory of 3,424 square kilometers, Yiling is the largest and most populous district of Yichang City.Urban construction-The district has invested one billion yuan in urban construction which has expanded the urban area to 8 square kilometers. The local infrastructure, transportation and environment have also been upgraded.

KEY S&T PROBLEMS RELATED TO THE THREE GORGES PROJECT

This article gives a highly capsulized introduction to the research on key S&T problems involving geology, silting-up, hydropower facilities, navigation locks and shiplift, construction technology, and eco-environ-mental con-sequences in the Three Gorges Project on the Yangtze River.

Last Chance to Save the Treasures of the Three Gorges

CONSTRUCTION OF the Three Gorges Dam on the Yangtze River will benefit society by adding to China's capac-ity for water conservation,hydro-power and navigation.Unfortunate~ly,it will also leave 22 cities and counties inundated,as a total land-mass of 632 square kilometers goes underwater.

Human Rights Protection Among Resettlers Displaced by the Three Gorges Project

The mammoth Three Gorges Dam is designed to displace 1.13 million people. Over the past ten years since the resettlement project started in 1993, 709,200 people or 62.76% have been resettled. Thanks to the principle of "resettlement by development," the Chinese government has paid full attention to protecting the property right, the right to employment, the right to residence and the rights and interests of disadvantaged groups. As a result, the resettlement project has given a powerful push to the overall economic and social progress and sustainable development.