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Taking two typical rivers in high mountains and steep gorge areas as example, this paper analyzes the spatiotemporal variability of the eco-hydrological characteristics and the driving forces leading to changes. Firstly, based on the species-environmental data processing, this paper adopts canonical correspondence analysis (CCA) method to identify the environmental factors influencing the distribution of river bank vegetation. Secondly, this study uses the ecological diversity index to represent the spatiotemporal variability of ecological characteristics. Thirdly, this paper uses the multiple correlation method to analyze the relationship between the hydrological factors and meteorological factors, and to identify the key factors leading to the hydrological regime changes. At last, based on the analysis of basin water quality data, this paper analyzes the regularity of spatiotemporal variability and its driving forces. By the systematic analysis on the outcome, we could get that the spatiotemporal distribution of eco-hydrological characteristics shows the regular changes from the upstream to downstream (from the north to the south), and the spatiotemporal variability of eco-hydrological characteristics is typical from the east to the west. Altitude, aspect and water distribution are the primary natural driving forces leading to the spatiotemporal variability of eco-hydrological characteristics; and exploitation and operation of hydroelectric power station, construction of road on the river bank, and basin land utilization are the main human driving forces. [ABSTRACT FROM AUTHOR]

Based on graphical and quantitative methodology of landscape ecology and Geo-information Tupu, this paper studies the landscape spatial-temporal evolution characteristics of the Yellow River Delta (YRD), which was built up by periodic physical swings of the Yellow River (YR) rump channel during 1855-2000. According to the research on spatial-temporal evolution of YRD and YR rump channel, we conclude that the Qingshuigou channel has reached its limit and a new flow channel for YR should be built up sooner or later. It suggests that the shift of YR channel should abide by its natural rules of flowing through depressions among previous channels and could be carried out by artificial efforts. The paper discusses the problems and alternate ways out for treatment of the high content of silt in the YR flow at the estuary. [ABSTRACT FROM AUTHOR]

The channel adjustment in a braided reach is very prominent in the fluvial processes of the Lower Yellow River, in which the process of bank erosion plays an important role, especially during the period of clear water scouring. The process of bank erosion is closely related to soil composition and mechanical properties of the riverbanks. In this paper, the recent bank erosion process in a braided reach between Huayuankou and Gaocun was firstly investigated after the water impoundment and sediment detention of the Xiaolangdi Reservoir, and then a field observation and indoor soil tests were conducted at 10 typical riverbanks in the braided reach. Through analyzing the experimental results, changes of riverbank-soil composition and mechanical properties were found, and the two real reasons causing serious bank erosion in the braided reach were identified. The following conclusions were drawn from this study: (I) the majority of riverbanks are made up of cohesive soil, and can be characterized by obvious vertical stratification structures of soil composition; (ii) these riverbanks are very erodible due to the lower clay-content and weak erosion-resistant strength in the bank soil, with its critical shear stress value (0.1-0.3 Pa) being much less than that of the average near-bank flow shear stress (2.0-3.0 Pa), which is one important reason causing serious bank erosion; (iii) frequent occurrence of bank failure during flood seasons usually results from the fact that the values of shear strength parameters such as the cohesion and internal friction angle decrease with the increase of water content in riverbank soil, and the value of cohesion reduces drastically from 34 to 4 kPa with the increase of water content, which is another important reason causing serious bank erosion in the braided reach. [ABSTRACT FROM AUTHOR]

Ecological effects of the cascade hydropower dam construction on ecosystems have acquired much concern from scientists with the expanding of dam development scales in the Longitudinal Range-Gorge Region. In the Lancang River region and Yuanjiang River-Red River region of the Longitudinal Range-Gorge Region (LRGR), an index system has been therefore established to assess the current ecological vulnerability and to predict the likely future ecological vulnerability of these two river regions after the dam constructions. Eight cascade hydropower dam construction scenarios have been established in this paper for forecast. Abrupt change characteristics of the ecosystem have been considered in the calculation. Economic benefits like current supply, navigation and tourisms of the dam construction have not been considered in the calculation. The results show that (1) the current ecological vulnerability values of Lancang River region and Yuanjiang River-Red River region are 0.34 and 0.43 respectively, which would rise to 0.90?0.91 and 0.86?0.89 respectively after the joint work of all the planned dams; (2) abrupt change would happen to both the Lancang River region and Yuanjiang River-Red River region in future; (3) interval construction with high human response is recommended for both the Lancang River region and Yuanjiang River-Red River region, after which their likely ecological vulnerability would rise to 0.56?0.62 and 0.42?0.43 respectively. These results provide a reasonable method and theoretical references to assess the ecological effects of dam construction, and also give prewarnings to other mainstreams of the Longitudinal Range-Gorge Region which are being planned to construct cascade hydropower dams. [ABSTRACT FROM AUTHOR]

This paper applied wavelet analysis to examining change tendency, multi-time scale variations, periodic and abrupt change characteristics of suspended sediment flux (SSF) of the Panlong basin in the Upper Red River, China. The results indicated that the SSF had increased from 1951 to 1997, but declined since 1998. The variations of the SSF had multi-time scale characteristics and the fluctuations varied in different time periods. Three periodic time scales, 4, 7 and 22 years, were determined. The 22-year periodic time scale, which was the most obvious one among the three time scales, extended through the whole research period, whereas the 4- and 7-year time scales were obvious only in certain time periods. There were 27 times of abrupt changes across the 4-year time scale, 16 times across the 7-year time scale and 5 times across the 22-year time scale, respectively. On the basis of social statistical and climate data analysis, we concluded that the human activities were the main reason that led to the changing tendency of the SSF, but the characteristics of the multi-time scale, periodic and abrupt change were mainly influenced by climate variations. [ABSTRACT FROM AUTHOR]

Both the climate change and human activities are the major influence factors to the sediment change in mountainous rivers. Based on the over 40 years' record, suspended sediment loads (SSL) change at the Manhao gauging station in the lower reaches of Yuanjiang River (upper Red River). In this paper, the variation of the sediment and its drivers were analyzed through different methods such as synchronous data comparison, traditional correlation, linear regression, and Granger causality. The results show that (1) the general trend of the annual average sediment concentration (SSC) and SSL at Manhao station is increasing from the 1960s to the 1990s, and there is a quick change period after 1984; (2) the SSL and SSC at Manhao station, during different periods of the 1960s, 1970s, 1980s and 1990s, are 1.87, 2.49, 3.12, 3.63 kg/m3, and 28.7×106, 40.3×106, 44.1×106, 60.3×106 t/a, respectively; (3) the correlation analysis and the Granger causality test proved that the climate changes in the catchment were the main driving factors to the sediment variation in the period of 1960s and 1990s, but the influence by the mountainous human actions on the sediment change is stronger than that by the local climate changes in the 1970s and 1980s; (4) the correlation between the sediment changes and the forest coverage change is negative, which further proves that the sediment changes are strongly affected by the human activities in the basin. [ABSTRACT FROM AUTHOR]

The relationship between the variations of the Nujiang River transboundary flow and the summer monsoon activity under the topographical effect of the Longitudinal Range-Gorge (LRG) is examined. The study is based on statistical analysis of the observed river flow data, and their correlation with the reanalyzed U/V wind fields of the National Centers for Environment Prediction (NCEP) and the National Center for Atmospheric Research (NCAR), and the data of the Outgoing Longwave Radiation (OLR) of the National Oceanic and Atmospheric Administration (NOAA). It is concluded that the transboundary river flow is predominantly concentrated in the wet or rainy season (from May to October), particularly in the summer or flood season (from June to August). There is a clear tendency for the transboundary river flow to increase with time since 1970s, particularly apparent since 1980s. Due to the topographical "east-west barrier and north-south corridor" effects of the LRG, the summer river flow variations are largely correlated with winds of the southerly and northerly at both high and low altitudes. In contrast, the river flow variations are apparently correlated with winds of the easterly and westerly only at the high altitudes, not at the low altitudes. Negative correlation between the OLR and the river flow variations is also apparent. These relationships are quantitatively described using two summer monsoon indices proposed in this paper. The index MI2 includes both dynamical and thermodynamical effects and gives a generally good representation of the transboundary river flow variations in the LRG region of the Nujiang River basin. Larger MI2 represents stronger summer monsoon activity and higher transboundary river flow, while smaller MI2 suggests weaker monsoon circulation and lower water flow. [ABSTRACT FROM AUTHOR]

Great achievements have been gained in assuring the safety of the lower Yellow River through arduous work in the past fifty years. But the disadvantages of boundary for river-flow are obvious, such as topography, tectonic movement and crustal stability. The main conflicts of less water and more sand, and the speeding up of sedimentation still exist, causing continuous river shrinkage. However, all the existing methods cannot completely avoid flood catastrophe, so a new control method needs to be explored. The method of changing-route based on geographical theory has always been a focus of debate over whether there are other feasible routes for the current Yellow River. From geoscientific point of view, this paper investigates whether there is a best feasible reservation route in Huang-Huai-Hai plain. Under the actual condition that the conflict between water and sand cannot be eradicated, the selection of the best reservation route should be the overlaying area of the optimum boundary conditions and the less social and economic loss. By detailed analysis of topography, tectonic movement, crustal stability and social-economic progress in the region of the lower Yellow River, the best reservation route is obtained by using the distance weighted function and the minimum cost function. The analysis result indicates that the reservation route can get rid of the influence of the elevation in central western Shandong Province, and the whole route flows through the Hal-Huang rift valley, which is good for channel stability. As to the basic parameters of water and sand movements, the gradient increases 36.2%, the length shortens 15.4% and the curvature reduces 12.2%. Using the reservation route can comparatively reduce the flood risk of the Yellow River, except that it will induce such problems as resettlement and relocation of towns, infrastructure reconstruction, water shortage in the abandoned area of the present route, as well as the resultant ecological and environmental degradation. But in contrast to the huge accumulative input to the harnessing of the Yellow River by the state, the absolute input of dealing with the above-mentioned problems is still acceptable. In the construction of corresponding infrastructures, using the reservation route will promote the region's socio-economic development and offer a rare chance of burgeoning. [ABSTRACT FROM AUTHOR]

Part II. Focuses on a study on the trace element composition and environmental geochemical characteristics of the karst river water and their controlling factors in the Wujiang River Valley, Guizhou, China. Effects of human activities on the Wujiang River Valley; Comparison of dissolved trace elements in river water with trace elements in the upper continental crust; Conclusion.

In groundwater-dependent ecosystems, groundwater circulation controls the overall water quality and ecosystem dynamics. Groundwater and vegetation across a 30-km groundwater transect linking oasis, desert and river in an extremely arid area were investigated with a series of soil profiles drilled into the unsaturated zone to understand groundwater circulation and its control on groundwater quality and surface vegetation in the extremely arid Lower Tarim River, NW China. Measurements have included water-table depth, water chemistry and water isotopes (H, O, H) for 15 water samples, soil moisture and chloride content for 11 soil profiles, and vegetation investigation. Results show that the groundwater in desert zone is characterized by slow recharge rate (pre-modern water), great water-table depth (6.17-9.43 m) and high salinity (15.32-26.50 g/L), while that in oasis (uncultivated land) and riparian zone is characterized by relatively fast recharge rate (modern water), small groundwater-table depth (3.56-8.36 m) and low salinity (1.25-1.95 g/L). Stable isotopes show that secondary evaporation takes place during irrigation in oasis. The vegetation characteristics (coverage, richness, evenness and number of plants) are closely related to soil moisture and water-table depth. Groundwater recharge from irrigation in oasis and from river in riparian zone sustains a better ecosystem than that in the desert area, where lateral and vertical groundwater recharge is limited. The more evapotranspirative enrichment may occur in the vegetated and water-rich riparian zone as compared to desert. This study also demonstrates the effectiveness of environmental tracers in studying ecohydrological processes in arid regions. [ABSTRACT FROM AUTHOR]

The report describes the use of solid-phase extraction (SPE) and LC/MS/MS to investigate the occurrence and distribution of 4 estrogens (estrone, 17β-estradiol, estriol, and 17α-ethynylestradiol) and 3 anti-inflammatories (ibuprofen, ketoprofen and naproxen) in the Zhangweinanyun River System (China). Relatively higher concentrations were observed for estrone, 17α-ethynylestradiol, and ketoprofen in the Wei Canal than in the Wei River and in the Zhangweixin River. The study suggested that there is a potential ecological risk of male fish feminization from estrogens in the Zhangweinanyun River System. [ABSTRACT FROM AUTHOR]

Environmental archaeology of archaeological sites on both sides of the Dachang section in the Daning River, the Three Gorges of the Yangtze River, shows that riverbed evolution has a great influence on the distribution of archaeological sites during the prehistorical and historical period, and it restricts human activity and the development of ancient culture. Field investigation, dating data, paleocurrent analysis of 100 gravels on the riverbed and archaeological excavation reveal that the riverbed of the Dachang section developed in the Shuangyantang region during the early stage, after about 30 kaBP it shifted westward gradually and reached the present place. Along with the westward shift, the focus of ancient culture changed for several times. In the Western Zhou Dynasty's period, the east riverbank of the Daning River was the main residential area. During the Han Dynasty, along with the westward shift, the living space of ancient people was no longer confined to the east riverbank and the focus of culture moved westward. Then the site became the main dwelling district. In the late Han Dynasty, the villages were flooded and the ancients had to immigrate to a high place. Tombs of the Han and the Jin Dynasties outcropped on the flood plain of the east bank because their surface sediments were eroded by several flood events and the westward shift of the riverbed. [ABSTRACT FROM AUTHOR]

As a fundamental category of river system, comparisons in diverse regions and types with quantitative parameters on meander morphology will help to distinguish different characteristics and approach formations and evolutions. It also can provide scientific basis of geomorphology for their protections and exploitation of the meander resources. Based on the images of Google Earth, meanders' parameters are proposed and then measured and calculated. The result suggests that incised meanders in the Jialing River are among the most complex, irregular and sinuous channels. Special river gradient, geological structures, strata and lithology, backwater effect of landform are key factors to shape meanders of the Jialing River. The evolution of meander in the Jialing River obeys the principle of minimum-maximum energy dissipation. Easy acquisitions of remote sensing data make regional and global comparisons possible, and then the differences of formations can be explored. The morphology can probably provide an evidence of antecedent river and demonstrate the channel incisions and crustal uplifts. Meander core in Chinese is named after the isolated hills in the Jialing River. The incised meander is a kind of resource and needs to be protected. [ABSTRACT FROM AUTHOR]

Water temperature (WT) is one of the important indicators of water body physical properties. Understanding the characteristics of spatial-temporal variation on WT in the river continuum will help to develop the rational river-water-resource utilization plan, to avoid the possible ecology crisis, and to take full advantages of the natural resources in the involved region. As the biggest international river continuum in Asia, the Lancang-Mekong river subregion (known as Greater Mekong Subregion, GMS) has become a famous economic, political, and ecological natural territory. This study examined the spatial- temporal distribution characteristics of the Lancang River water temperature, using the observational data of WT values from 11 hydrological stations in 1960s. Furthermore, the WT differences between Yunjinghong hydrological station (one representative station in China) and Chiang Saen hydrological station (one representative station in Thailand) were analyzed. Results indicated that: 1) Water temperature was higher in the lower part of the river continuum than the upper part. Latitude variation is the main influencing factor. This effect is more obvious in dry season than in rainy season, more obvious in winter than in summer, and more obvious of the average minimum WT than the average maximum WT; 2) WT difference between the upper and the lower parts of the river continuum was decreasing due to little increase of WT in the upper part (Yunjinghong hydrological station) and obvious decrease of the WT in the lower part (Chiang Saen hydrological station) during the research period. Therefore, the parameters of WT are affected by the latitude, and the Lancang-Mekong river continuum lies in the north-south direction, so the tropical aquatic creatures, such as the tropical aquatic fishes, cannot survive in the upper part of this river continuum in winter season, while in summer season, the tropical aquatic creatures properly swim to the upper stream. The water temperature in the lower Mekong River is mainly influenced by the regional water temperature and regional climate change. [ABSTRACT FROM AUTHOR]

According to the study on the aquatic environment of the typical lakes in the middle and lower reaches of Yangtze River, lake eutrophication is a process in which the lake ecosystem degenerates, resulting in the deterioration of the water quality due to the enrichment of the nutrients. Moreover, the succession of lake ecosystem and change of water quality both couple well with the evolvement of trophic state. Then the conceptual model is mentioned and ten lake states are classified. Based on these, the authors analyzed the eutrophication processes of the typical lakes in the middle and lower reaches of Yangtze River. The large lakes with taking in - sending out water typical of Poyang Lake evolve from State 1 before the 1980s into State 2 after the 1980s, the large and medium lakes typical of Taihu Lake evolve from State 1-2 in the 1960s into State 8 in the 1980s then into State 9 in the 1990s, the medium and small shallow lakes typical of Honghu Lake evolve from State 1 in the 1960s into State 2 after the 1980s and the small city (suburban) lakes typical of Donghu Lake evolve from State 2 in the 1960s into State 9 after the 1970s. Further, the 1980s is the key conversion period of the lakes of various types typical of Poyang Lake, Honghu Lake and Taihu Lake converting into mesotrophic state, the 1990s is that of Taihu Lake into eutrophic state and the 1970s is that of the small city (suburban) lakes typical of Donghu Lake into eutrophic state. The series of nutrient evolvement of different typical lakes are similar, but the processes are not synchronous, which is related to the various human and natural driving mechanisms in lake basins. [ABSTRACT FROM AUTHOR]

Combined with materials measured on leaves water potential of Populus euphratica oily in the process of ecological water delivery in the lower reaches of Tarim River, the influence of ground-water depths and soil salinity on leaves water potential of P. euphratica was analyzed. We found that there was evident negative correlation between the leaves water potential of P. euphratica and ground-water depths. The deeper the ground-water depths were, the lower the leaves water potential of P. euphratica was, the more serious drought stress P. euphratica suffered from. Besides, there was evident negative correlation between the soil salinity and the leaves water potential of P. euphratica. The bigger the soil salinity was, the lower the leaves water potential of P. euphratica was, the more serious drought stress was indicated from which P euphratica suffered. For sections rather distant for Daxihaizi Reservoir as well as for those places of wells rather distant from the river course, ground-water depths and the soil salinity were high; the leaves water potential of P. euphratica was low. The leaves water potential of P euphratica can reflect the degree at which P euphratica suffers from drought and salt stress, and has an important reference meaning in analyzing proper ground-water depths for the survival and growth of P. euphratic in the lower reaches of Tarim River. [ABSTRACT FROM AUTHOR]

The river corridor areas in the middle and lower reaches of the Tarim River are dominated by the traditional green corridors along the river section from the Qara Reservoir in Yuli County to the Taitema Lake in Ruoqiang County, which plays an important role in the social and economic development in the Tarim River Watershed with a extremely significant ecological functions. The buffer zones perpendicular to the watercourse were defined along both riversides at a 5-km interval beginning from the watercourse (10 km wider) using the method of the buffer zone analysis. The landscape pattern indexes of each buffer zone were calculated, and the indexes of the main landscape patterns were analyzed so as to reveal the radiative effect and the characteristics of the river corridors on landscape and patch levels. The results show that the radiative width is generally 30 km in the study area, and can be up to 50-70 km in sub- region FG1 because the study area is located in two drainage basins, with an ecological interstitial zone between them. The landscapes of woodlands and wetlands are generally distributed within the 10 km buffer zone (it means that the buffer zone is 5 km away from the watercourse; the same hereafter) along both riversides: Moreover, the closer the buffer zone is to the watercourse, the higher the patch density and the largest patch index are. In the ecological and environmental regeneration for the study area, the extent of ecological effect of the river corridors must be fully considered, and the projects must be scientifically and rationally planned and designed. [ABSTRACT FROM AUTHOR]

The eco-physiological response and adaptation of Populus euphratica Oliv and Tamarix ramosissima Ldb during water release period were investigated. Nine typical `areas and forty-five transects were selected along the lower reaches of Tarim River. The groundwater table as well as plant performance and the contents of proline, soluble sugars, and plant endogenous hormone (ABA, CTK) in leaves were monitored and analyzed. The groundwater table was raised in different areas and transects by water release program. The physiological stress to P euphratica and T ramosissima had been reduced after water release. Our results suggested that the groundwater table in the studied region remained at -3.15 to -4.12 m, the proline content from 9.28 to 11.06 (mmol/L), the soluble sugar content from 224.71 to 252.16 (mmol/L), the ABA content from 3.59 to 5.01 (ng/g FW), and the CK content from 4.01 to 4.56 (ng/g FW), for the optimum growth and restoration of P. euphratica indicated by the plant performance parameters and the efficiency of water application was the highest. The groundwater table in the studied region remained at -2.16 to -3.38 m, the proline content from 12.15 to 14.17 (mmol/L), the soluble sugar content from 154.71 to 183.16 (mmol/L), the ABA content from 2.78 to 4.86 (ng/g FW), and the CK content from 3.78 to 4.22 (ng/g FW), for the optimum growth and restoration of T ramosissima indicated by the, plant performance parameters and the efficiency of water application was the highest. The rational groundwater table for the restoration of vegetation in the studied region was at -3.15 to -3.38 m. [ABSTRACT FROM AUTHOR]

An interdisciplinary comprehensive survey was conducted in middle and late June 2003 with the Multi-Parameter Environmental Monitoring System YS16600 and water sample analysis in the sea off the Changjiang River mouth. The Changjiang diluted water (CDW) extended off- shore with a bimodal structure during the observation, one extending toward the southeast, the other toward the north- east. The main axis of the CDW extended toward the northeast. A severe red tide with wide spatial extent and brown water color happened. Chlorophyll-a (Chl-a) distribution near the Changjiang River mouth also presented a bimodal structure, and its position and shape were roughly consistent with the extension of the CDW. Water sample analysis indicated that the serious eutrophication produced by the huge amount of nutrient load via the Changjiang River was the main cause of red tide bloom. The dominant algal specie at the most measurement stations was skeletonema costatum. There existed three centers of higher Chl-a concentration, locating at (122.45°E, 31.5°N), (122.4°E, 30.8°N) and (123.25°E, 30.0°N), respectively. The red tide at (122.45°E, 31.S°N) was located in the major modal of CDW and higher turbid seawater, its dominant algal specie was prorocentrum dentatum with density 223 × 106 ind/L. The red tide at (122.4°E, 30.8°N) was located in the second modal of CDW and lower turbid seawater, its dominant algal specie was skeletonema costatum with density 1.0 × 107 ind/L. The dominant algal specie at (123.25°E, 30.9° N) was Heterocapsa circularisquama horiguchi with density 2.0 × 106 ind/L, which was found for the first time forming red tide in the sea off the Changjiang River mouth. [ABSTRACT FROM AUTHOR]