Abstract:In the flood season of 1993, Taihu Lake reached its high water level of 4.51m, or the third highest one after 1949.Some areas of the basin were suffered from flood and waterlogging disaster.In this paper, the rainfall and flood regime, the comparison of rainfall and flood characteristics for typical flood years of 1993, 1991 and 1954 are illustrated.The flood and waterlogging disaster and the benefit of water conservancy projects are also analyzed.Rain season in the basin is from May to July.But in 1993, the temporal distribution of rainfall was unusual.The rainfall was concentrated in August and high water levels in rivers also appeared late in August.The spacial distribution of the rainfall was characterized by the follows: (1) The rainfall in the upper reaches was concentrated in the West Zhejiang mountain area;(2) The rainfall in Taihu Lake region was heavy;(3) The rainfall in the lower reaches was concentrated in Dianmao and HangJiahu regions.Water levels in the rivers of some hydrographic stations in Dianmao and Hangjiahu regions were higher than those in the heavy flood year 1991.Strong flood flow from the upper reaches,high rainfall intensity in the local area,low discharge capacity of the rivers in the lower reaches are the main causes of flood disaster.In order to improve flood control operation and harnessing plan, more researches should be done for some rainfall patterns and flood patterns of different typical flood years.

Abstract:According to the abundant data collected in field and laboratory experiments by the State Collaboration Research Group on Evaporation and Heat Loss from Water Surface since 1976 and a number of historical data observed in hydrological stations located in the typical regions in China, the elements influencing evaporation from water surface and the nonlinear interactions between them are determined, new non-dimensional parameters and new structure of the formulae are recommended.The constant coefficients in the formulae are determined based on the statistical analysis on measured data.The formulae for calculating daily evaporation and heat loss coefficient from water surface by using the data of regular hydrometeorlogical elements (water temperature} air temperature, vapour pressure;wind speed;and atmospheric pressure) have been obtained.The formulae were tested by 1860 group data collected from both natural lakes (reservoirs) and thermal polluted water bodies during various seasons in different climate regions of China, and also from laboratory experimental data.It is shown that the accuracy of this suggested the formulae is higher than that of other existing formulae.This paper consists of two parts.This is the second part, which includes the test of the formulae, influence of hydrometeorlogical elements on evaporation, calculation of heat loss coefficient, and conclusion.

Abstract:Yuqiao Reservoir is an important regulating-impounding reservoir of the diversion project to channel the Luanhc water to the city of Tianjing.An analysis of the flow field affected by the wind is the main way of studying the transportation-diffusion of pollutants and eutrophication of Yuqiao Reservoir.Based on the governing equations of fluid movement, and water surface shear stress under the action of the wind, a numerical simulation system of flow field has been developed by means of moving Alternating Directional Implicit Method.The simulation results are in very good agreement with the original data measured in the last 4 years.In addition, the flow field under the effects at stationary and unstationary situations of wind on 3 typical hydrographic years is predicated, a color picture of flow field given out, and its application disciissed.

Abstract:Taihu Lake, one of the five largest freshwater lakes in China, is situated in the middle of the Yangtze River Delta, which is inhabited by more than 100 million people and provides one seventh of China, s Gross National Product.Marine and brackish organisms found at the bottom (275cm, about 11280 a B.P.) of the sediment core indicates that sea water intruded to the lowland areas and river valleys of the present western Taihu Lake during the last major rise in sea level.The sea water intrusion to Taihu Lake occured 2000 years ago earlier than previously indicated.Evidence also shows that sea water intrusion was limited, affecting only a part of the present Taihu Lake.Evidence from the lake sediment analysis suggests that this lake underwent major changes from a brackish to a freshwater environment between 5000 and 5300 a B.P.Major changes in sediment were noted between 35-45cm (5070-5330 a B.P.) reflecting a period during which inorganic carbon was drastically reduced, primary production (Chl.a and pigments) increased significantly, and many marine and brackish organisms disappeared and were replaced by freshwater forms.This evidence indicates that prior to,5cm, Taihu Lake received constant inputs of sea water, and perhaps existed as a bay or an estuary.After that period, the water gradually became fresh.At depths above 35cm, Taihu Lake turned completed lacustrian under Increasing impact of wind-driven lake currents, and expanded substfintially to reach its present size.This lake was oligotrophic, the eutrophic conditions in the present lake developed during recent decades as a result of increased nutrient loadings.

Abstract:Hulun Lake, the fifth largest lake in China, is located in the west side of Hulun Buir Prairie.It was seldom studied and understood before due to the remote border district.The observation and sampling of the modern sediment in Hulun Lake has been carried out and the mineral composition and the sedimentation rate analysed recently.The surficial sediments of Hulun Lake are distributed unevenly, for the lake is linked to the influxes of the Herlen River, the Orxon River and the ancient Harlar River.Grainsize analysis of 7 sediment samples in the northwest demonstrates that the median size of most sample is 7.0-9.2φ, falling in the size fraction of clay-very fine silts.Mineral identification by microscope and XRD analysis for the sediment shows that the sediments are such allogenic minerals as quartz, feldspar, mica and heavy minerals and authigenic minerals, mainly calcite.Carbonate content of the sediment samples ranges from 10.1 % to 17.6% indicated by chemical analysis, which is linked to higher salinity and supersaturation to carbonate of the lake water.^2l0Pb dating was tested for a short core in the central pwirt (site HL8) of the lake and the sedimentation rate was calculated using CIC model.The average sedimentation rate is 0.25 cm/a above lOcm-depth of the core and 0.05 cm/a in 10-12cm, implying higher sedimentation rate since 1959 A.D.Based on the hydrologyical data, the lake level rose gradually begiiiing from the 1950s and up to its historical highest in the 1960s.It is inferred that the influx sediment amount increased as the lake level rose.

Abstract:Gucheng Lake, situated in the southeast of Gaocheng County, Jiangsu Province, surrounded by mixed evergreen/deciduous broad,leaved forests, lies between the north and middle subtropical zone in monsoon Asia area.This paper deals mainly with the systematic palynological research on more than 57 samples from a column core with a depth of 6.2m in Gucheng Lake.According to the spore-pollen diagram, 8 assemblage zones have been distinguished in an ascending order as followss 1.Cyclobalanopsis-Casianea-Liquid ambar zone(6.3-5.lm);2.Pinus-Querous-Polypodiaceae zone (5.1-4.15m);3.Cyclobalanopsis-Graminea-Typha zone (4.15-3.2m);4.Greunines-Artemisia-Quercus zone(3.2-2.3m);5.Quercus-Pinus-Castaned zone (2.3-1.75m);6.Graminea-Artemisia-Quercus zone (l.75-1.lm);7.Quercus-Pinus-Caslanea zone(l.1-0.45m);8.Pinus-Graminea-Artemisia zone(0.45-0m) From the above statement, 8 phases of the paleovegetation succession and climate fluctuation seem to be shown in the past 4000 years, and 8 climate periods can be listed in the ascending order for convenience of correlation: 1.3700-3000 a B.P.: warmer and moist;2.3000-2500 a B.P.: temperate-cool and a little wet;3.2500-2000 a B.P.: warm and wet;4.2000-1500 a B.P.: temperate-cool and a little wet;5.1500-1000 a B.P.;warm and wet;6.1000-800 a B.P.: temperate-cool and a little dry;7.800-500 a B.P.;temperate and wet;8.500a B.P.-present: cool and a little dry.Moreover, according to the analysis of stable carbon isotope of organic matter, TOC, diatom and historical records, the influence of climate and human activity on environment is also discussed.

Abstract:This paper studies the effects of DO, pH, temperature and the growth of bacteria on the release of phosphorus from Wuli Lake sediment.The result of experiments shows that the quantity of phosphours released from sediments into the water body was getting greater with decrease in DO, pH, temperature but increase in the growth of bacteria.The filtrate of the anaerobic release test may stimulate the growth of Scendestnus obliquus, but not the growth of Selenaslrum capricornutum.It is showed that filtrate of the aerobic release test can stimulate neither of the algae.

Abstract:By using enclosure method,the Microcystis bloom which disappeared after 1985 in Donghu Lake (Wuhan, China) was successfully recovered, and some causal factors of the resumption and disappearance of the summer Microcy at is bloom were dealt with.According to the biomanipulation theory, the authors designed a series of stocking experiments in which three domestic fishes-silver carp, bighead carp and grass carp were introduced.The results show that in the silver carp and bighead carp stocking enclosures, the bloom vanished in a short period (15 days), and no change took place in the grass carp stocking enclosures, whereas in the fish-free enclosures, the bloom was even more abundant.It is concluded that planktivorous fish have great effects on the plankton community structure of the enclosures where Aficrocy bloom occurred.Also, the fluctuation of various forms of carbon, nitrogen and phosphorus were fully discussed in order to show some implications of their effects on Microcy stis bloom.

Abstract:This paper deals with the growth and stock assessment of Capias auratns aurtus L.collected from Wanghu Lake during December 1984 to May 1986.The relation between the body weight and body length can be expressed in terms of the power function equation: W=4.2184×10^-5 L^22,9274.The growth equation is L_t285.82[1-e^{-0.2640(t+0.1213)}] and W_i=653.30[1-e^{-0.2640(t+0.1213)}]^2.9274.The coordination of inflexion point is at l_t=3.95Y and W_i=192.41 g.Using Jones length-based cohort analysis, the standing srock size and biomass were estimated to be 1.0905×10⁶ in number and 53355kg respectively.The theoretical abundance and yield were also calculated under different fishing intensities in accordance with Thompson-Bell predictive.In order to maintain a sustaining fisheries, a discussion on the rational exploitation of the stock has been proposed.

Abstract:The salt lakes over Qinghai-Xizang Plateau is characterized by large numbers, wide distribution, complete types, rich and important natural resources in China.Except large amount of carbonate, sulpfiate, borate and chloride deposits, there are brine resources, rich in trace elements and dispersed elements, especially Li,B,Mg.The high grade,great reserves of trace elements have taken the dominate position in salt lake resources in China, and is also rarely seen in other salt lakes in the world.There are various kinds of salt lake resources over Qinghai-Xizang Plateau, for example, solid salt deposits, saline brines, inorganic salt deposits and also various salt lake bio-resources.Halite, mirabilite, trona, carnallite, bischofite, sylvite, antarcticite, celestite, borates (borax, ulexite, pinnoite, kurnakovite) have formed sedimentary deposits of different sizes for direct utilization.Besides, there are saline brines, rich in K, Mg, B, Li, Rb, Cs, U, Th for comprehensive use.In some salt lakes like Dongcuo, Gahai, there are many kinds of halobionts which may be used as a new kind of salt lake resources in the future.

Abstract:In 1988,four clossed fish ponds (4-1,4-2,4-3,4-4) were selected to study the different types of main cultivated fingerlings in fish ponds in the saline-alkali wetland in Yucheng County of Shandong Province.In pond 4-1, 4-2, 4-3, 4-4, Oreochromis aureus, Hy pophthalmichtkys molilrix, Cyprinus corpio, Cienopharyngodon idellus are the main cultivated fishes, respectively.During 4-10 months, the abundance, biomass and the key environmental factors in the four fish ponds were tested.According to the changes in the major population of plankton, such as Protoza, Rotifera, Cyanophyta, Chlorophyta, Bacillariophyta, Cryptophyta and Euglenophyta, the steady and synchronous characteristics of the plankton in four different types of the fish ponds were analysed.In addition, the relationship between the environmental faotor, especially the nutritional factor, and the pleinkton were studied.As the growth and reproduction of plankton need an abundant nitrogen and phosphorus, there was a proportion suitable to N and P of about 15-30.1.During the cultivation period, the abundance of plankton had a positive interrelation with water temperature, but the water temperature reached an appropriate point, showing negative interrelation.The different proportions of the ferite feeding fish in ponds led to different species of plankton.In the pond of main cultivated Hypophthalmichthys moliltrix, the primary productivity is not on the decline.In favourable conditions, there would be more abundeince of plankton.

Abstract:The utilization and harnessing of Chaohu Lake is discussed in the paper.