Table of Content

    15 September 1998, Volume 53 Issue 5 Previous Issue    Next Issue
    Ye Qingchao
    1998, 53 (5):  385-392.  doi: 10.11821/xb199805001
    Abstract ( )   PDF (407KB) ( )   Save
    In the 25-year period from 1972 to 1997, there were 20 years in which the Yellow River experienced flow interruptions. As a result of repeated flow interruptions, the river channel has shrunk steadily, leading the river to a new stage of development. Repeated flow depletion has added to the difficulty of flood control in the delta region and brought severe negative impact on it s environment. This paper examines the problems of flood control and water supply and their causes. A side from natural causes, human facto rs are especially impo rtant in the river’s flow interruptions. Among the majorreasons for flow depletion are little precipitation, reduced runoff volume, accelerated pumping for irrigation, flow detention by water and soil conservation measures, low capability of flow regulat ion by reservoirs, poor management and waste of water resources. In recent years, environmental changes in the Yellow River delta region are manifested in the following areas. First, the river channel has clearly shrunk and the water table has risen significantly. Three phases of sedimentation in the river channel can be identified. Sediments decreased during 1950~ 1960; they disp layed a U-shaped pattern in the 1964~ 1985 period; and they rose from 1986 to 1995. An understanding of the changes in the channel in the last phase can help us bet ter understand the current conditions of flood control in the lower reaches and the mouth of the river. The August 1996 flood level at Lijin Station reached 14. 7m , the highest ever recorded. This levelwas 0. 94m and 1. 19m higher than the levels for 1958 and 1992, respectively. If the river continues to experience flow interruptions, a discharge of 104m3/s at Lijin may result in large-scale flooding, with the po ssibility that the river may shift its course. Second, the sho rtage of water for drinking and indust rial use has become increasingly serious in recent years. In 1992, there were 83 days in which the channel below Lijin dried up, causing critical shortage of drinking water for two million people and half a million livestock. In 1995, there were 122 days in which the channelwas dry, forcing a large number of indust ries to cease or reduce production and resulting in a loss of 600 million yuan. To ensure sufficient drinking water for humans, the amount of water charged too ilwells was reduced by 2. 6 million m3, causing a reduction of 3×106 tons of crude oil production, or a loss of 216 million yuan. Third, pumping water from the river for irrigation has increased rapidly, from 6 billion m3 in the 1950s to 29. 8 billion m3 in the 1990s, the latter being 50 percent of the river’s annual natural runoff. Fourth, soil and water conservation uses about 2. 8 billion m3 of water per year, which accounts for 9 percent of the average annual runoff of 30. 7 billion m3 fo r the 1986~ 1994 period. Fifth, the capability of water regulat ion by reservoirs is quite low. The reservoir at Sanmen Go rgeat the beginning of the flood season (June) can only hold 1. 4 billion m3 of water. Lastly, poor management and serious waste of water are also reasons for repeated flow interruptions in the river.
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    Li Yongping, Qin Zenghao, Duan Yihong
    1998, 53 (5):  393-403.  doi: 10.11821/xb199805002
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    Utilizing the historical tide records at seven tide-gauge stations in the Shanghai region,the characteristics of the mean annual Eustatic sea level(MAESL)are analyzed.It is shown that the MAESL in the region has been rising in the last 100 years,at the meanliner rate of 0.1 cm/a.The rising rate was especially rapid in the last 30 years.Those findings are consistent with the results obtained by other scientists who have estimated the magnitude of MAESL rise in the North Pacific and the East China Sea.A statistical model fitting the variation of the MAESL is established to estimate the MAESL rise.It is estimated by extrapolation of data that the MAESL will rise above the 1990 level by 4cm,9cm and 18cm in 2010,2030 and 2050,respectively.Our estimates are similar to those suggested by IPCC in 1992 and 1995 and by the academicians of the Department of Geoscience,Academic Sinica in 1994.According to research by the Shanghai Academy of Geotecnical Engineering&Geology in 1994 and the Shanghai Observatory in 1996,the ground subsidence in the Shanghai region due to compaction of sediments will be 10cm,15cm and 18cm,whereas the regional crust will subside by 2cm,4cm and 6cm below the 1990 level by 2010,2030 and 2050,respectively.Accepting these values and using our own estimated rates of MAESL rise,we further estimated that the mean annual relative sea level would rise above the 1990 level by 16cm,28cm and 42cm in the same three years.However,taking a variety of undetermined factors into consideration,the reasonable values of the relative sea level rise for the same years would be between 15cm and 20cm,25cm,35cm,40cm and 50cm,respectively.
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    Jing Xueqing
    1998, 53 (5):  404-412.  doi: 10.11821/xb199805003
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    Early in 90's,Chinese government opened the border regions's gate toward the border countries.In the same time,the border regions in China began to be developed largely.What is the border regions prospect of opening and developing? This is the question that the paper will answer.There are five factors that affect opening and developing the border regions,namely,political relations,opening level,natural resource and condition,economic level,convenient level of communications,etc.We have got the answer through analysing the five factors and studying the examples of opening and developing the border regions between the USA and Canada,and between USA and Mexico.There are 15 countries round Chinese border,namely,D.P.R.K orea,Russia,Mongolia,Kazakhs tan,Kirghizstan, Tadzhikistan,Afghanistan,Pakistan,India,Nepal,Sikkim, Bhutan, Myanmar, Laos and Vietnam.After the founding of People's Republic of China, because of long-term continuous cold war and harsh international environment,China's wish to cooperate and contact with all countries in the world can not been realized.China and the neighboring countries'political relation also went through twists and turns,had some times of quite tense relation.In 50's,China and India's relation was very tense.In 60's China and the Soviet Union's relation was worsened.At the end of 70's,China battled with Vietnam.But from 80's,the world situation changed,peace and development became a dominent matter.China and the border countries'political relation improved largely.Friendly phase that didn't arise before appears.The border countries and China maintain good political cooperation relations now.After the end of the cold war, the overwhelming majority of the border countries have executed opening policies, and had economic and trading relations with China. The border regions' natural resources in China and in the border countries are very rich and their developing potentialities are large. But natural conditions of developing the resources are not very good, and some regions' natural conditions are even very adverse. The economic level of the border regions in China are quite low稵he border countries are all developing countries are all developing countries and ditricts.Their economic growth degrees are not high either.Some are even very backwand稡ecause of separation of the large mountain ranges that surround the borders of China,and very adverse natural environment of the border regions,the transport and communication institutions which are engaged in economic and trading action are poor.These are the basic conditions of opening and developing the border regions in China.The conditions decide its macro-prospect.Through study we put forward three basic estimates about the macro-prospect of opening and developing border regions in China.(1)O pening and developing the border regions in China can get a steady development.The macro-prospect is quite optimistic.Because of long-term geographic gradient,economic divergence at different degrees and mutual reqirements between China and its border countries,the frontier resource development and economy and trade exchange will develop,will not stop so long as China and the border countries maintain so good political relations as the present ones,and mutual opening.But the developing speed will not be very fast either,it will only develop steadily,because China and its neighboring countries have a mutual fitting process through their economic adjustment,and have a problem of bearing ability of economic development.(2)The very concentrated economy regions can not form in the border regions between China and the border countries like the eastern border regions between USA and Canada.Natural conditions of the border regions in China are not good,such as climate,topography,et c.,so the resource development and economic development are retricted quitely.As in forward position of military defense,the political and military functions of the border regions play a principal role,and the economic development level is ver low,so the border regions can not become developed regions in a short time on such a weak economic basis.Because of the undeveloped economy and very bad natural conditions,tran sport facilities of the border regions are very disappointing,and the clear degree of economic and trade contacts is not good.This will also restrict economic development of the border regions.The neighboring countries'border regions adjoining with Chin a are in the same situation basicly.(3)Some border regions in China can become more developed economic regions,such as Tumen River district of the northeastern China,connective parts of Lanchang River-M aigong River of the southwestern China and Yili River district of northwestern China,etc.These regions belong to superier locations in the border regions.Their conditions of opening and developing are better in China.Their natural conditions are more advantageous,the economic level and opening degrees are higher,and the transports outward or inward are more convenient.Especially these regions have got attention and in terest from the developed countries and international economic organizations.The developed countries and international economic organizations raise funds and take part in development and construction of the border regions.This will largely accelerate development of the border regions.
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    Mao Hanying
    1998, 53 (5):  413-421.  doi: 10.11821/xb199805004
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    Establishing comprehensive regulative system of regional sustainable development is an important guarantee for its sustainable development.The aim consists of following asperts:Main target should be econom ic and social sustainable development,and basic target should be resources sustainable use and ecological environment improvement.Measures such as sustainable developmental ability cultivation and traditional developmental model reform,market mechanism improvement,and comprehensive regulation of regional policy,economic law,technical and administrative means,should be taken so that regional economy and society can develop efficiently,and these measures can coordinate population,resources and ecological environment harmoniously.Shandong is one of the fast developmental provinces in coastal areas in China.From 1979~1995,its provincial GDP(computed in comparable price)increased by 11.9%per year.In the former 6 years before 1990s,it was 14.74%,which was 2.1 and 4.4 percents higher than that of the national average in the same time.Natural resources such as water,cultivated land,energy these resources were over consumed as its economy increased continuously with over high speed.As a result,ecological environment has worsened and some other problems broke out (for example,economic benefit decreased,disparity widened between the east and the west with in Shandong).After a comprehen sive study on Shandong’s sustainable developmental indicators system,the author points out that Shandong belongs to a soft sustainable developmental type.
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    Zheng Fen li, Kang Shaozhong
    1998, 53 (5):  422-428.  doi: 10.11821/xb199805005
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    Soilerosion on loess slopes has clear vertical zonation.Eacherosion zone has its own characteristics of erosion and sediment yield,and the zones tend to have mutual influence.The intensity and energy of rainfall affect the distribution of eroded sediments on a slope.As rainfall intensity and energy increase,the location of maximum sediment yield changes from the rillerosion zone to the shallow gully erosion zone.The intensity of sediment yield changes with different modes of erosion.
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    Tang Lijun
    1998, 53 (5):  429-437.  doi: 10.11821/xb199805006
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    A rational spatial pattern of natural landscape is the aim of landscape planning and landscape designing in natural scenic spot.In this paper,landscape ecological methods have been introduced to describe and analyze quantitatively the landscape constitution and landscape lanning in Sheshan Scenic Spot,the sole forest scenic spot in the suburbs of Shanghai city.Five landscape ecological indices such as landscape diversity,landscape dominance,landscape evenness,landscape fragmentation and landscape isolation were chosen to judge the spatial patterns of natural landscape.Results shown that the present landscape structure was dominated by farm land which constitute 39.3%of the total area,with the lowest isolation index(0.135).
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    Wang Shouchun
    1998, 53 (5):  445-452.  doi: 10.11821/xb199805008
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    Alarge-scale sea aggression along the coast of the Bohai Sea in north China occurred at the Christian era.Signals of the sea aggression were recorded in,an ancient Chinese classic writhed in the end of lst century.which revealed that a“massive sea spill”had developed there in 48BC,and after 2 A.D.extensive sea aggression occurred Using the ancient Chinese documents,we conclude that after sea aggression,The coast line remained stable for one and a half centuries,but from the 4th to the 7th century.the coast line receded gradually.
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    Wang Lijun, Zhang Chaosheng, Zhang Shen, Chen Nengjian, Yang Liu
    1998, 53 (5):  453-462.  doi: 10.11821/xb199805009
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    The use of rare earth elements(REEs)by Chinese industry and agriculture has increased over the years,and many studies exist on its effects on soils and plants.To better understand the impact of REEs in China’s aquatic environment,we collected data from the sediments and suspended matters in both raw and filtered waters from the Guangzhou section of the Zhujiang(Pearl)River.The study area covers the lower reaches of all three branches of the Zhujiang:the Dongjiang,the Xijiang and the Beijiang.The contents of the REEs in the samples were detected by ICPMS analysis,and a speculation analysis was carried out to examine the sediments and suspended matters.
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