Economic Structure Transformation and Land Use Change of the Changjiang River Basin

1 Introduction Economic development in any country or region entails a long process of structural change in production as GDP and income per capita rise. In addition, economic de- velopment requires a long period of structural transfor- mation in materials inputs through reallocating natural resources (Cipolla, 1962). Land, as a crucial element and a key factor of production, is always the best witness of such transformations. In China, one of the largest countries in the world, 13.5% of its…     

Safety analysis of water resources and eco-environment in Shiyang River Basin

The research on the present situation of soil and water development and utilization in Shiyang River Basin shows that water resources and eco-environment situation in this area are near the edge of collapse. Since the water crises occurred in the 1970s, problems caused by continuous decrease of water resources have been becoming serious year by year and eco-environment crisis occurred as a consequence. Up to now, 10 380ha of irrigated lands have been abandoned due to sand coverage and water shortage in the basin. Ground water was over exploded in Wuwei and Minqin because of water shortage. Ground water table in many places dropped under 5m (which is the ecology water table level), thus about 3000ha of Elaeagnus angustifolia forest come to dead and another 5800ha become feeble, and wind-drift sand near the oasis become alive. According to the current situation, if water utilization scope was not enlarged, a water transfer volume of 600×10⁶m³/a from other areas will be suitable to keep water resources and eco-environment safety in the basin, and also 70×10⁶m³/a will be left as spare water. Under this condition the water resources and eco-environment of the basin can reach the critical safety line of 2.032×10⁹m³/a; or if 180×10⁶m³ of water can be transferred from other areas, the water resources can reach the safety warning line of 1.732×10⁹m³/a. Foundation item: Under the auspices of the National Natural Science Foundation of China (No. 40235053) and Lanzhou Jiaotong University "Qinglan" Foundation Biography: ZHANG Ji-shi (1963-), male, a native of Tongwei of Gansu Province, senior engineer, specialized in water resources and climate change in Northwest China. E-mail: zjs1963@yahoo.com.cn; hangjs@mail.lzjtu.cn     

IMPACTS OF FUTURE SEA LEVEL RISE ON SALT WATER INTRUSION IN THE CHANGJIANG RIVER ESTUARY

Sea level rise could increase the salinity of an estuary by altering the balance between fresh water and salt water. The implications of sea level rise for increasing salinity have been examined in the Changjiang (Yangtze) River estuary. By correlative analysis of chlorinity, discharge and tidal level and calculation of two-dimensional chlorinity, distribution of the Changjiang River estuary, the changes of the intensity and lasting hours of salt water intrusion at Wusong Station and the changes of chlorinity distribution in the South Branch of the Changjiang River estuary have been estimated when future sea level rises 50-100 cm. The intensity of salt water intrusion in the future will be far more serious than current trend.     

MIXING OF SALT WATER AND FRESH WATER IN THE CHANGJIANG RIVER ESTUARY AND ITS EFFECTS ON SUSPENDED SEDIMENT

Using field hydrological data, the relationship between the mixing of salt water and fresh water and the tidal range/ high tidal level in the Changjiang (Yangtze) River estuary is discussed, and the transporting and concentrating of suspended sediment in the estuary were also analysed in respect to the circulation, flocculation and stratified interface resulting from mixing.The calculation results by two-dimentional box model have confirmed the effects of the circulation on the concentrating of suspended sediment in the estuary. The conclusions derived from this work have deepened the understanding on the mixing in the Changjiang River estuary and are of significance in bo'th theory and practice.     

THE BACKGROUND VALUES OF RARE EARTH AND RADIOACTIVE ELEMENTS IN WATER SYSTEM OF SOURCE AREA OF THE CHANG JIANG RIVER

Using neutron activation analysis method we determined contents of rare-earth and radioactive elements (La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Cs, Rb, Sb, Sc, Sr, Ba, U, Th) in source water system of the Changjiang (Yangtze) River, which is mainly composed of the Tuotuo River, the Chumaer River, and the Buqu River. The contents of these elements in the unflltered water have a great variation and a close correlation with the water turbidity. The contents of these elements in filtered water only have a little variation and are lower than those in the unflltered water. The variations in contents of these elements in sediments are also very little. These elements in the unifiltered water are in geometric distribution, except Sc. Most of the elements in sediments are in arithmetic distribution, but Cs, Sb, Th, are in deviation distribution. The contents of most of these elements in the river source area correspond to the contents of fresh water of the earth. Most of these elements have a little variation in their c     

Simulated circulations off the Changjiang （Yangtze） River mouthin spring and autumn

The circulations off the Changjiang mouth in May and November were simulatedby a three dimension numerical model with monthly averaged parameters of dynamic factors in this paper. The area covers the East China Sea (ECS), Yellow Sea and Bohai Sea. Simulated results show that the circulation off the Changjiang mouth in spring and autumn is mainly the Changjiang runoff and Taiwan Warm Current (TWC). The Changjlang discharge is much larger in May than in November, and the wind is westward in May, and southward in November offthe Changjiang mouth. The runoff in May branches in three parts, one eastward flows, the other two flow northward and southward along the Subei and Zhejiang coast respectively. The Changjiang diluted water expands eastward off the mouth, and forms a strong salinity front near the mouth. Surface circulation in autumn is similar to that in winter, the runoff southward flows along the coast, and the northward flowing TWC becomes weaker compared to that in spring and summer. The bottom circulations in May and November are mainly the runoff near the mouth and the TWC off the mouth, and the runoff and TWC are greater in May than in November.     

A STUDY ON THE RELATIONSHIPS OF THE NUTRIENTS NEAR THE CHANGJIANG RIVER ESTUARY WITH THE FLOW OF THE CHANGJIANG RIVER WATER

Investigations from August, 1985 to July , 1986 showed that the high concentration area of PO4-P , SiO3-Si and NO3-N gradually reduced with the reduction of the area of the Changjiang River diluted water from summer, autumn to winter , and that the seasonal distributions and variations of the nutrients concentrations were mainly controlled by the river flow and were also related to the growth and decline of phytoplankton . The conservation of SiO3-Si and NO3-N in the estuary in the flood season was poorer than that in the dry season .. The behaviour of PO4-P in the estuary shows that aside from -biological removal, buffering of PCU-P is possible in the estuary . The highest monthly average concentrations and annual average concentrations in the river mouth were respectively 0.88 and 0.57 umol/L for PO4-P,191.5 and 96.2 umol/L for SiO3-Si, and 81.6 and 58.6 umol/L for NOs-N . The Changjiang's annual transports of PO4-P , SiO3-Si and NO3-N to the sea were about 1.4×104tons , 204.4×104 tons and 63.6×104     

A contrast analysis on the load character of the Changjiang River and the Huanghe River

According to the analysis of grain size, mineral composition and inclusion in quartz grain of the suspended and bed load sampled from the Changjiang (Yangtze) River and the Huanghe (Yellow) River, the authors reveal the differentiation of loads between the two rivers. In the Huanghe River the size of suspended load is coarser than that in the Changjiang River, while the bed load is on the contrary. Through heavy mineral analysis, the biotite content of the Huanghe River loads is much higher than that of the Changjiang River, and the monomorillonite content of the former is about two times higher than the latter. All those may be attributed to the effects of different material sources and hydraulic conditions on load. The analysis of inclusion in quartz grain definitely illustrates the environmental difference of material sources between the two rivers. In the meantime, it provides a new method in seeking source of river load. Subsidized by the National Natural Science Foundation. This paper is attributed to careful guidance from Prof. Wang Ying & Prof. Shi Yunliang.     

A contrast analysis on the load character of the Changjiang River and the Huanghe River

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.The Studies of Regional Water Circulation Patterns in the Yerqiang River Basin

Based on the characteristic of ＇one river one oasis＇ in the arid areas, the Yerqiang River Basin, which is the largest irrigated area of Xinjiang, is taken as an example in this paper, and the regional water circulation pattern is investigated through the analysis of 60 groups of isotope data in the basin. From the phreatic evaporation data analysis of different soils, we study the law of phreatic evaporation, complete the research of the main consumption path of the groundwater, and improve the assessment precision of water resources. The transformation mount of regional water resources are predicted by calculation, which provides a scientific basis for water resources assessment and allocation in arid regions, and offers a new method for the study of regional water circulation patterns.     

Evaluating Suitability of Multiple Precipitation Products for the Lancang River Basin

Global reanalysis precipitation products could provide valuable meteorological information for flow forecasting in poorly gauged areas, helping to overcome a long-standing challenge in the field. But not all data sources are suitable for all regions or perform the same way in hydrological modeling, so it is essential to test the suitability of precipitation products before applying them. In this study, five widely used global high-resolution precipitation products—Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources(APHRODITE), National Centers for Environmental Prediction Climate Forecast System Reanalysis(NCEP-CFSR), Climate Hazards Group InfraRed Precipitation with Station Data(CHIRPS), China Gauge-based Daily Precipitation Analysis developed by China Meteorological Administration(CMA) and Agricultural Model Intercomparison and Improvement Project based on the NASA Modern-Era Retrospective Analysis for Research and Applications(AgMERRA)—were evaluated using statistical methods and a hydrological approach for their suitability for the Lancang River Basin. The results indicated that APHRODITE, CMA, AgMERRA and CHIRPS were more accurate precipitation indicators than NCEP-CFSR in terms of the multiyear average and seasonal spatial distribution pattern, all of the CHIRPS, Ag MERRA and APHRODITE perform better than CMA and NCEP-CFSR at the small, medium and high precipitation intensities ranges in subbasin11 and sunbabsin46. All five products performed better in subbasin46(a low-altitude region) than in subbasin11(a high-altitude region) on the daily and monthly scales. In addition to NCEP-CFSR, the other four products all presented encouraging potential for streamflow simulation at daily(Yunjinghong) and monthly(Yunjinghong, Jiuzhou and Gajiu) scale. Hydrological simulations forced with APHRODITE were the best of the five for the Yunjinghong station in capturing daily and monthly measured streamflow. Except for NCEP-CFSR, all products were very good for hydrological simulations for the Gajiu and Jiuzhou stations.     

Global charm of the Changjiang River Delta

Based on the theory of geo-economy, under the new situation of global economy, information network and China‘s entry into WTO, also with the holding of APEC (in 2001) and the International Exposition in the near future, the Changjiang (Yangtze) River Delta is striding toward the spectacular international multi-polar situation and becomes one of core regions with high-speed development. Facing the ocean and world all along, leading the progressive tides of the age and scintillating the splendor of the nation, she does advance with time. Through a long period of irrigation projects construction and intensive operation of lands in previous agricultural society, the artificial wetland ecosystem with a positive cycle had ever been formed in this region. At present, environmental pollution and urban expansion resulted from post-industrialization are being rectified. The delta will be the paradigm of industrial and agricultural modernization along the sustainable development road. With the rapid development of urbanization,she has been one of the regions with the highest density population and high urbanization level. Taking the Changjiang River estuary and the Hangzhou Bay as two parts, she is continuously strengthening and adjusting her interior structure, expanding mothball space and constructing the oriental modem ″logistics center“ to link the whole world. The butterfly-style urban system of the Changjiang River Delta is flying, probably engendering earthshaking “butterfly effect“.     

Textural research on the main source of the Changjiang River

The Chinese people began to research the main source of the Changjiang (Yangtze) River 2,400 years ago. Limited by the scientific level, they did not discover it. The Tuotuo River was determined as the main source of the Changjiang River in the 1970s. However, this was not correct, because when comparing the length of the Tuotuo River with the Dam River, the glacier length at the headwaters was added to the Tuotuo River, resulting in that the Tuotuo River is 1 km longer than the Dam River, keeping in mind that the glacier can not be regarded as part of the river. In the summer of 1986, we investigated the source of the Changjiang River, we accurately measured the length of both the Tuotuo and Dam rivers, we discovered that the Dam River was 353.1 km long, and the Tuotuo River was 346.3 km long, the Dam River thus being 6.8 km longer than the Tuotuo River. The discharge of the Dam River is 196.18 m³/sec., 2.6 times as large as that of the Tuotuo River, that of the Tuotuo River is 75.10 m³/ sec. The drainage area of the Dam River is 1.8 times as larger as that of the Tuotuo River; the drainage area of the Dam River is 30,715.7 km², the Tuotuo River is 16,691.0 km². Through synthetic analysis of the factors mentioned above, we came to the conclusion that the main source of the Changjiang River is the Dam River instead of the Tuotuo River.     

Observed residual currents off the Changjiang （Yangtze） Rivermouth in summertime of 1959 and 1982

Data taken in two large scale ocean observations in China in summer 1959 and 1982 were used to analyze the residual current off the Changjiang (Yangtze) River mouth. The currents at surface off the mouth in July 1959 and 1982 flow northeastward and eastward due to the river discharge, the current speed was larger in 1982 than in 1959. All the bottom currents flow landward due to baroclinic effect. The surface current was controlled by the river runoff and the Taiwan Warm Current (TWC). A return current at surface off the mouth was observed in September 1959. In general, the bottom currents were controlled by the TWC in most study area in addition to the runoff near the mouth. Although driven by 3-D model with the monthly averaged forces (river discharge, wind stress, baroclinic effect, open boundary water volume flux and tidal mixing) in August, the simulated circulations were basically consistent with the observed ones with episodic time manner.     

TRMM及GPM降水数据在高寒内陆河流域的准确性评估

降水数据的准确性和时空分辨率成为水文过程模拟的关键.卫星遥感降水资料的日益丰富为资料缺乏区的水文模拟带来了新的突破.本研究拟在资料缺乏、下垫面复杂,观测难、建模难的柴达木盆地高寒内陆河流域—巴音河中上游,基于近5年的TMPA 3B42、GPM IMERG V5及GPM IMERG V6逐日降水数据和气象站点观测数据建立...     

THE CHANGE OF THE GENERAL FORM AND THE TRANSPORT OF THE WATER， LOAD AND SALT ABOUT THE NORTH－BRANCH OF THE CHANGJIANG RIVER MOUTH

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A STUDY ON REGULARITY OF DROUGHT AND FLOOD IN THE CHANGJIANG RIVER VALLEY DURING LAST 10 CENTURIES

According to historical records, there are 264 drought and flood years, occurred in the upper and middle reaches of the Changjiang (Yangtze) River during last 1020 years from 961 to 1980. The evolutionary law and developing trend of drought and flood years are studied. The distribution of drought and flood years are non-uniform and the dry and flood seasons in a year are concentrated. At the angle of monsoon circulation, at present the climate in the upper and middle reaches of the Changjiang River is just in the late stage of frequent drought period and the early stage of least flood period. In addition, the cycle of drought and flood and the feature of drought and flood occurred in the upper, middle and lower reaches of the Changjiang River are analyzed. It shows that the short period less than 10 years is in the majority, and the drought and flood occurred most frequently in the middle and lower reaches of the Changjiang River.     

CALCULATION AND ANALYSIS ON CHANGE OFAGRICULTURAL WATER CONSUMPTIONIN THE CHANGJIANG DELTA

Climate changehasprofound impacts onhumanl－splratlon Intense，and Is unfavo毗Ie to crop’s growth，ty·Lllmale change and a series ofconsequences caused 帅s沏ds ic reducmn of crop yle恰．We什angjlangby It have been paid more and more attention In evew Delta Is one of＊theari＜ most lmpoFtant grain－producingarearesearch held．Climatic warming In the future will have of China．Though the Chan用fang Delta provides largegreat Influence on the China’s agriculture．As the report amo…     

Major problems of sustainable development along the bank area of the Changjiang River

TheChangiiangRiverisrichinfreshwaterandwaterpowerresources,themeanrunoffandwaterpoweroftheriverareabout37%and52%respectivelyoftotalonesofChina.Inaddition,theChanaiiangRiverhastheimmensenavigationpotentialandvaluableshorelineresources,thenavigablelengthreaches364okmandtheallshorelinelengthisabout6OOokmfromYihinCitytotheestuary.Moreover,theChangiiangRiver,withtheadvantagesofsuitablelocationandbroadhinterland,crossesEast,MiddleandWestEco-nomicZonewithdifferenteconomiclevelsofChina,soitsuniq…     

Is Precipitation the Dominant Controlling Factor of High Inorganic Nitrogen Content in the Changjiang River and Its Mouth？

The main reasons for the high content of inorganic N and its increase by several times in the Changjiang River and its mouth during the last 40 years were analysed in this work. The inorganic N in precipitation in the Changjiang River catchment mainly comes from gaseous loss of fertilizer N, N resulting from the increases of population and livestock, and from high temperature combustions of fossil fuels. N from precipitation is the first N source in the Changjiang River water and the only direct cause of high content of inorganic N in the Changjiang River and its mouth. The lost N in gaseous form and from agriculture non-point sources fertilizer comprised about 60% of annual consumption of fertilizer N in the Changjiang River catchment and were key factors controlling the high content of inorganic N in the Changjiang River mouth. The fate of the N in precipitation and other N sources in the Changjiang River catchment are also discussed in this paper.