Ganjiang River Research Articles

Spatial-temporal variations of pollutant fluxes of inflow and outflow of Lake Poyang (2008-2012)

研究鄱阳湖入、出湖污染物通量是加强鄱阳湖及长江水功能区限制纳污红线管理的前提,是建立鄱阳湖水质预测模型的基础.基于2008 2012年鄱阳湖8条主要入湖河流、出湖口的逐月水量、水质同步监测资料,根据污染源特征优选算法,计算总磷(TP)、氨氮(NH₃-N)、高锰酸盐指数(COD_Mn)的入、出湖污染物通量,并分析时空变化特征及影响因素.结果表明:(1)出湖口和乐安河入湖口断面的NH₃-N、TP及昌江入湖口断面的TP,以点源污染为主,采用每月瞬时通量作为月平均通量的算法更准确;其余以非点源污染为主,采用瞬时污染物浓度与月平均流量之积来计算月平均通量更准确.(2)2008 2012年COD_Mn、NH₃-N和TP年平均入湖通量分别为304398、53063和9175 t,年平均出湖通量分别为367436、45814和8452 t.8条入湖河流每年的入湖水量、COD_Mn通量和个别年份的NH₃-N、TP通量小于出湖,这主要是因为未计算区间产流及相应排污和采砂引起的内源污染.(3)入、出湖污染物通量在年际间主要受水量影响而呈现W型波动变化趋势,COD_Mn、NH₃-N、TP入湖通量及COD_Mn出湖通量均集中在汛期,NH₃-N、TP出湖通量则是冬季较多(低水位下湿地植被净化作用受限).入湖TP、NH₃-N、COD_Mn通量主要来自赣江、信江、乐安河,而NH₃-N、TP浓度最高的是乐安河、信江.;Research on pollutant fluxes of inflow and outflow is an essential prerequisite to establish water quality prediction model of Lake Poyang, and strengthen the management of pollutants receiving capacity threshold in the water function zones of Lake Poyang and Yangtze River. This paper estimated the influxes and outfluxes of total phosphrous(TP), ammonia nitrogen(NH₃-N), permanganate index (COD_Mn) of Lake Poyang, analysed their spatial-temporal variations and main influencing factors, based on appropriate estimation methods, and characteristics of pollution sources for inflow(8 main rivers) and outflow of Lake Poyang, using the synchronous monthly water quality and quantity data during the period of 2008-2012. The results showed:(1) Point source was the main source for TP, NH₃-N of outflow and Le'an River inflow, and for TP of Changjiang River inflow. Therefore, applying monthly instantaneous flux as monthly average flux is more accurate for estimation. For other pollutants at the monitoring sites, applying the product of instantaneous pollutant concentration multiplying monthly average flow as monthly average flux is more appropriate. (2) During 2008-2012, annual average influxes of COD_Mn, NH₃-N and TP were 304398, 53063 and 9175 t, respectively, and annual average outfluxes were 367436, 45814 and 8452 t, respectively. For annual water quantity and COD_Mn flux, and TP flux and NH₃-N flux of some specific years, inflow values of 8 rivers were smaller than those of outflow values due to the fact that flows and pollution fluxes from the intervening basin, and internal pollutants discharges from sediments accelerated by dredging had not been included in this study. (3) During 2008-2012, both annual inflow and outflow pollutant fluxes showed a wavy variation trend, mainly influenced by water quantity. Higher TP, NH₃-N, and COD_Mn influxes of 8 main inflow rivers and COD_Mn outflux mainly occurred in high-water periods, while higher TP, NH₃-N outfluxes mainly occurred in winter (as in lowerwater periods, the biological purification of wetland plants were inhibited). TP, NH₃-N and COD_Mn influxes were mainly from Ganjiang River, Xinjiang River and Le'an River, while the highest concentration of TP, NH₃-N occurred in Le'an River and Xinjiang River.

Optimization of coagulant for raw water in Ganjiang River in winter

The paper aims to determine the optimal coagulant for raw water in the Ganjiang River during the winter. To explore their removal effect on turbidity and organic matters, respectively, by using FeCl3, Al2 (SO4)3, polyaluminum chloride, and polymeric aluminum ferric chloride as coagulant, there has been a total of six-jar test conducted. It was discovered that the removal rates of turbidity and organic maters vary a lot according to different raw water quality.

Accuracy and spatio-temporal variation of high resolution satellite rainfall estimate over the Ganjiang River Basin

Based on spatial interpolation rainfall of the ground gauge measurement, we proposed a method to comprehensively evaluate and compare the accuracy of satellite rainfall estimates (SREs) at three spatial scales: 0.25°×0.25° grid scale, sub-catchment scale and the whole basin scale. Using this method, we evaluated the accuracy of six high-resolution monthly SREs (TRMM 3B42 V6, 3B42RT V6, CMORPH, GSMaP MWR+, GSMaP MVK+ and PERSIANN) and revealed the spatio-temporal variation of the SRE accuracy based on spatial interpolated rainfall from a dense network of 325 gauges during 2003–2009 over the Ganjiang River Basin in the Southeast China. The results showed that ground gauge-calibrated 3B42 had the highest accuracy with slight overestimation, whereas the other five uncalibrated SREs had severe underestimation. The accuracy of the six SREs in wet seasons was remarkably higher than that in the dry seasons. When the time scale was expanded, the accuracy of SRE, particularly 3B42, increased. Furthermore, the accuracy of SREs was relatively low in the western mountains and northern piedmont areas, while it was relatively high in the central and southeastern hills and basins of the Ganjiang River Basin. When the space scale was expanded, the accuracy of the six SREs gradually increased. This study provided an example for of SRE accuracy validation in other regions, and a direct basis for further study of SRE-based hydrological process.

年径流模拟方法比较研究

基于两参数月水量平衡(TPMWB)模型的基本结构框架，本文设计了两种年径流模拟方法(TPMWB-1和TPMWB-2)。TPMWB-1方法以实测月降水量和蒸发量作为输入，通过TPMWB模型首先得到模拟月径流量，然后逐月累加得到模拟年径流量；而TPMWB-2方法以实测年降水量和蒸发量作为TPMWB模型输入，直接得到模拟年径流量。作为比较，多元线性回归(MLR)方法也被用于年径流模拟。在东江、赣江和汉江流域的52个子流域上对3种方法进行了年径流模拟。研究发现，3种方法均取得了令人满意的模拟效果。TPMWB-2方法在年径流模拟中的成功应用表明，TPMWB模型结构也适合直接用于年时间尺度的径流模拟，可在更多湿润或半湿润地区年径流模拟中推广应用。 Based on the structure of two-parameter monthly water balance (TPMWB) model, two annual streamflow simulation methods, which were called as TPMWB-1 and TPMWB-2 respectively, were designed in this paper. For the TPMWB-1, observed monthly precipitation and potential evaportranspiration were taken as the inputs, monthly runoff was firstly simulated by using the TPMWB model, and the annual streamflow was subsequently calculated by the sum of the corresponding simulated monthly runoff. For the TPMWB-2, observed annual precipitation and potential evaportranspiration were taken as the inputs, and annual streamflow was then directly simulated. To provide a comparison with the simulation results of these two methods, the multiple linear regression (MLR) method was also used to estimate the annual streamflow. Finally, 52 sub-catchments in Dongjiang, Ganjiang and Hanjiang River Basins were chosen for comparison analysis of the runoff simulation results of 3 methods. The results show that all methods obtain good simulation results. From the successful application of TPMWB-2 methods it is concluded that the structure of TPMWB model is suitable and recommended to directly simulate the annual runoff in more humid and semi-humid regions.

基于RS与GIS的赣江上游流域生态系统服务价值变化

It is of significance to study the effect of land use change on ecosystem service values.Based on TM image data in 1990,1995,2000 and 2005 of the Upper Reaches of Ganjiang River,this paper analyzes the land use change and its consequent changes in ecosystem services value in the watershed from 1990 to 2005 by RS and GIS technology.The results show that the total ecological services value exhibits an increasing trend from 1990 to 2005.The total ecological services value of the upper reaches of Ganjiang River has less change from 1990 to 1995,which the total ecological services value has been continuously increasing and it is to exist the larger fluctuation in somea ecosystem function services from 1995 to 2005.The ecosystem services value sensitivity index of each land use type is less than 1,indicates that the ecosystem services value of the Upper Reaches of Ganjiang River lacks flexibility on its service value index.

Study on Adsorption and Desorption of Suspended Sediments to Phosphorus in Ganjiang River

Based on isothermal adsorption experiment and adsorption/desorption kinetic experiment,the adsorption and desorption characteristics of suspended sediments in Ganjiang River to phophorus was studied.The results show the phosphorus adsorption of sediment reaches balance basically in 2~4h; the adsorption capacity is increased with the increment of the initial concentration of phosphorus,and decreased with the increment of sediment conentration. The isothermal adsorption of phosphorus by sediment can be fitted preferably by Langmuir and Freundlic model. The adsorption and desorption process can be fitted by Langmuir equation.The phosphorus desorption of sediment reaches balance basically in about 14h. The phosphorus desorption capacity of sediment is decreased with the increment of sediment concentration.

Fatigue Reliability Updating Evaluation of Existing Steel Bridges

AbstractThrough modern nondestructive inspection (NDI) techniques, fatigue cracks can be detected with varying accuracies in steel bridge structures, and consequently assessment and updating of fatigue reliability can be performed. A probabilistic fracture mechanics method based on the Bayes theorem using information from NDI has been demonstrated to update the relevant parameters of crack growth models effectively. Using the probabilistic characteristics of the NDI techniques, the probabilistic fatigue failure method, and the Bayes theorem, a procedure for assessing and updating the fatigue reliability of existing steel bridge components is presented. Data collected from two steel bridges, the Zhejiang Street Bridge and Ganjiang River Bridge, are used to illustrate the fatigue reliability assessment and updating method. In the case study, the suspender β‐T curves of the Zhejiang Street Bridge and Ganjiang River Bridge are determined after inspection and updating. It is found in this research that the fat...

Prediction of the Maximum Riverbed Erosion Depth nearby the River-Crossing Tunnel in Nanchang Reach of Ganjiang River

Nanchang rail transit project line1 was programmed to drill through the Ganjiang river bottom of the reach approximately 700m downstream from the Nanchang Bridge. The prediction of maximum erosion depth of the river bed at the tunnel location was strongly needed. This paper described the composition and evolution of the river bed in the engineering reach, established a 2-D flow and sediment mathematical model to calculate and analyze the river bed evolution at the tunnel location, selected the typical hydrological years of erosion calculation, catastrophic floods and a long series of hydrological years as the hydrological conditions, and finally obtained the maximum erosion depth under different hydrological conditions. These results will provide technical reference for the tunnel design.

Study on Characters of Nitrogen Adsorption and Desorption of Sediment in Ganjiang River

Sediment has the function of adsorption and desorption of the nitrogen in water body. This study provides the theoretical basis of calculating the nitrogen content discharged into the Poyang Lake. The results show the nitrogen adsorption of sediment reaches balance basically in about 4~ 6h, the adsorption capacity is increased with the increment of the initial concentration of nitrogen, and decreased with the increment of sediment conentration.The isothermal adsorption of nitrogen by sediment can be fitted preferably by Henry and Langmuir equation.The adsorption and desorption process can be fitted by Langmuir equation.The nitrogen desorption of sediment reaches balance basically in about 8~14h.The nitrogen desorption capacity of sediment is decreased with the increment of sediment concentration.

Starch grain analysis reveals Late Neolithic plant utilization in the middle reaches of the Ganjiang River

Plant utilization is poorly known in South China as compared to North China. Fanchengdui, Zhuweicheng, Shinianshan, and Yinjiaping, which date back to 5-4 ka BP, are typical Neolithic sites located at the middle reaches of the Ganjiang River in Jiangxi Province. Due to the lack of systematic plant archaeological work, only rice straw and husk residues have been found in some archaeological sites in Jiangxi Province. Thirteen stone tools excavated from these sites were examined in this study. The results showed that among the plants utilized are Coix spp., Oryza spp., Vigna spp., plants from the tribe Triticeae, roots from some plants of Zingiberaceae, and other species of roots and tubers. More than 457 grains were retrieved from the 13 stone tools. The fact that Coix spp. were found in all stone tools suggests that these species were a major food source during the Neolithic era. In addition, 28 starch grains of Oryza spp. were found in 8 stone tools. The analysis also revealed that not only seeds of Gramineae but also those of Leguminosae, Zingiberaceae and other species of roots and tubers are among the plants utilized in the four Fanchengdui culture sites. These results indicate that ancient plant utilization was rather diverse, and this study elucidates the prehistoric agricultural systems of South China.

Stable isotope analyses in otoliths of silver carp: a pilot study in identification of natal sources and stock differences

Silver carp, Hypophthalmichthys molitrix, is one of the four major fishes in China for fishing and aquaculture. The Yangtze River and associated waterbodies are important home to silver carp. In this study, we collected 135 otoliths of juvenile silver carp from the two rivers and the Poyang Lake, and analyzed for stable oxygen and carbon isotope ratios (δ18O and δ13C). The isotopic data and correlation of δ18O versus δ13C showed a clear separation and significant differences (p < 0.001 for both δ13C and δ18O) between otoliths from the Ganjiang River and the Yangtze River at δ18O values around −10‰. The Poyang Lake samples were overlapped with those of the Ganjiang River, but distinctly different from the Yangtze River samples. These isotopic signatures agree well with the previous genetic investigation results that there are marked distinctions between one population in the Ganjiang River and the other in the Yangtze River, and the Poyang Lake population belongs to the Ganjiang River rather than to the Yangtze River. Thus we concluded that stable isotope analyses of otoliths can be effectively used to study natal sources and stock differences of silver carp.

Chronology and provenance of aeolian sediments from Poyang Lake area in the middle reaches of the Yangtze River in China

Aeolian deposits (including aeolian sands and loess deposits) are widely distributed in the Poyang Lake region located in the middle reaches of the Yangtze River. The chronology and provenance, and their environmental implications, of these aeolian sediments have been debated for decades. Based on the OSL chronology, sedimentology, grain size analysis, and elementary data, we conclude that: (1) The source materials for the aeolian sediments in the Poyang Lake region originated from the local flood plains of the Yangtze River and its tributary Ganjiang River, whose fine materials were transported by the strong northwestern winter monsoon wind. (2) Aeolian deposits occurred throughout Late Pleistocene. Loess has a timing interval of 160–25 ka, concentrating in 115–50 ka. Sand accumulated as early as 115 ka, actively occurred during 85–80 ka. (3) Compared with the channel of the Yangtze River of today, the channel was further to the north before 80–85 ka in the Last Interglaciation, and shifted southward afterward.

Community structure of macrozoobenthos and biological evaluation of water quality in lower reaches of Ganjiang River

2009年6月(丰水期)、11月(枯水期)和2010年4月(平水期)对赣江下游流域大型底栖动物群落结构进行调查研究,共鉴定出大型底栖动物3门15科25种.结果表明,赣江下游流域大型底栖动物群落结构具有明显的时空变化.生物密度最大值(145.9±81.8 ind./m²)出现在6月,最小值(89.6±15.9 ind./m²)出现在4月;生物量的变化则相反,最大值(90.1±25.4 g/m²),出现在4月,最小值(62.9±20.9 g/m²)出现在6月;干流的生物密度在6月、11月和4月均明显高于支流,而生物量在11月低于支流.Shannon-Wiener多样性指数(H')、Margalef丰富度指数(D)和Pielou均匀性指数(J)在6月、11月和4月的时间尺度上以及干流、支流的空间尺度上均出现明显的变化,在11月份,这3类指数均表现为最高,6月则均为最低;干流的H'和D在6月和4月均低于支流,而J在这3个时间段内则均是支流高于干流,表明支流大型底栖动物的群落结构较干流更为多样、均匀和稳定.H'和D的结果表明赣江下游流域水质均受到不同程度的污染,其中干流的污染程度较支流更为严重.;Macrozoobenthos community structure in the lower reaches of Ganjiang River was investigated in June (wet season) and November (dry season) 2009 and April (normal-water period) 2010. A total of 25 species from 15 families were recorded. Results showed that temporal and spatial variations of the macrozoobenthos community structure were obvious in the lower reaches of Ganjiang River. The mean maximal density (145.9 ± 81.8 ind./m²) occurred in June while the minimum (89.6 ± 15.9 ind./m²) appeared in April. On the contrary, the mean maximal biomass (90.1 ± 25.4 g/m²) occurred in April while the minimum (62.9 ± 20.9 g/m²) appeared in June. Their mean densities in the main stream were always higher than those in branches. However, the mean biomass in main stream was lower than that in branches in November. Temporal and spatial variations of three indices (including Shannon-Wiener index, Margalef index and Pielou evenness index) were apparent. Maximal values of all the indices occurred in November while the minimum appeared in June. The Shannon-Wiener index and Margalef index in the main stream were lower than those in branches in June and April; however, the Pielou evenness index in branches was constantly higher than that in the main stream, which showed that the community structure of macrozoobenthos in branches was more diversiform, uniform, and stable than that in the main stream. According to Shannon-Wiener index and Margalef index, the lower reaches of Ganjiang River was polluted to a certain extent and the main stream was more serious.

Double-Wall Cofferdam of Hero Bridge Calculation

Hero Bridge is an extraordinarily huge bride across northern branch Ganjiang River, in the city of Nanchang. Main tower adopted single column slanted pylon space twist face back cable structure. Its construction is based on double-wall cofferdam method. The paper discuss thecalculation of key step and key position for the key technology in terms of double-wall cofferdam and platform underwater construction, Which include the design of the base construction and double-wall cofferdam,steel cofferdam construction, the calculation and checking of the cofferdam and so on.

Calculation of Hongdu Bridge Foundation Construction

Hongdu Bridge is an extraordinarily huge bride across northern branch Ganjiang River, in the city of Nanchang. Main tower adopted single column slanted pylon space twist face back cable structure. Its construction is based on double-wall cofferdam method. The paper discuss thecalculation of key step and key position for the key technology in terms of double-wall cofferdam and platform underwater construction, Which include the design of the base construction and double-wall cofferdam,steel cofferdam construction, the calculation and checking of the cofferdam and so on. The whole length of 9.5 km, except the starting period of about 2.4 km for roadbed type, the other sections of approximately 7 km. The project always invests about 18 Billion yuan.

Spatio-temporal patterns of hydrological processes and their responses to human activities in the Poyang Lake basin, China

Poyang Lake is the largest freshwater lake in China, and plays a major role in flood mitigation, restoration and conservation of the ecological environment in the middle Yangtze River basin. Sediment load and streamflow variations in Poyang Lake basin are important for the scouring and deposition changes of this lake. However, these hydrological processes are heavily influenced by human activities, such as construction of water reservoirs, and land-use/land cover changes. By thorough analysis of long series of sediment and streamflow obtained from five major hydrological stations, we systematically investigated the spatial and temporal patterns of these hydrological processes and the hydrological responses to human activities using the Mann-Kendall trend test, the double cumulative mass curve and the linear regression method. The results show: (1) no significant change in streamflow followed by an increasing tendency after the 1990s that turns to be decreasing about 2000; and (2) a sharp increase of sediment load during the late 1960s and 1970s triggered by extensive deforestation (during the “Cultural Revolution” in China) followed by a tendency to decrease after the early 1980s. Construction of water reservoirs has greatly reduced the sediment load of the Poyang Lake basin, and this is particularly the case in the Ganjiang River, where the sediment load changes may be attributed to the trapping effects of the Wan'an Reservoir, the largest water reservoir within the Poyang Lake basin. There is no evidence to corroborate the influence of water reservoirs on the streamflow variations. It seems that the streamflow variations are subject mainly to precipitation changes, but this requires further analysis. The current study may be of scientific and practical benefit in the conservation and restoration of Poyang Lake, as a kind of wetland, and also in flood mitigation in the middle Yangtze River basin that is under the influence of human activities. Citation Zhang, Q., Sun, P., Jiang, T. & Chen, X.-H. (2011) Spatio-temporal patterns of hydrological processes and their hydrological responses to human activities in the Poyang Lake basin, China. Hydrol. Sci. J. 56(2), 305–318.

Some Insights into the Genesis and Evolution of Dunefields Along the Lower Ganjiang River and Surrounding the Poyang Lake

Based on a body of relevant literature and field investigations, this paper presents some insights into the genesis and evolution of dunefields along the lower Ganjiang River and surrounding the Poyang Lake, Jiangxi Province, central China. After analyses and comparisons, it concluded that: 1) the dunefields in the Poyang Lake valley occurred at lest during late Quaternary, not Holocene, and there could be theoretically mid-Quaternary dunefields; 2) the essentials of genesis and evolution of dunefields exist during both Quaternary glaciations and dry seasons and periods in the Holocene, especially in specific sites such as Shaling of Xingzi County and Laoyemiao of Duchang County; 3) considering the distinct location and spatial characters of the Poyang Lake valley, as the existence of “Easten Asian Cold Trough” is possible and reasonable, glacial and aeolian processes as a coupled complex should be concurrent and synergic in a much larger spatial extent, the widespread dunefields of late Quaternary suggest more possibly the existence of corresponding glacial products in the region; 4) the future explorations in such vulnerable and distinct environments entail more original ideas and approaches as well as research and analysis techniques in order to obtain more valuable results.

Molecular Weight Distribution and Removal Characteristics in Source Water of Ganjiang River

Raw water in the Nanchang district of Ganjiang River and water after conventional treatment were estimated by the method of the ultra filtration to find out its molecular weight distribution. According to the result, the molecular weight distribution of the raw water in Ganjiang River shows the trend which has the large edges and small middle part, that is to say; the organic matter mainly centralizes in a scope whose molecular weight are larger than 30ku and less than 1ku, the middle part occupies a relatively small proportion. In winter low-water season, there is little organic matter in the river and the small molecular of the organic matter plays a dominant role. In the season of high-water, the amount of organic matter increases, and while the small molecular of organic matter decreases and large molecular of organic matter becomes a large part. The popular water purifying process in Nan Chang city is just to mainly remove the large molecular in the organic matter, which leads to a bad result，the low efficiency of removing the small molecular.

Observed trends and jumps of climate change over Lake Poyang Basin, China:1961-2003

本文利用1961-2003年间鄱阳湖流域14个气象站的气温、降水量、蒸发量等观测数据和8个主要水文站的流量数据,研究该时段内鄱阳湖流域的气候变化趋势、突变及其空间分布的差异.研究表明,鄱阳潮流域气温和降水均在1990年发生突变,继而呈现显著的上升趋势;在季节变化上,冬季平均气温在1986年发生突变,增温显著;夏季降水量和夏季暴雨频率均在1992年发生突变增加,暴雨频率增加是夏季降水量增加的主要原因;蒸发皿蒸发量和参照蒸散量均呈现显著下降趋势,该变化在夏季尤为明显.上述变化趋势均以1990s最为显著,这与长江流域气候变化趋势基本一致.在空间分布上,饶河水系、信江水系和赣江下游等气候变化更为显著.笔者认为,鄱阳湖流域气候变化在长江流域中比较突出.该流域1990s暖湿气候在加强;气温的升高、降水量和暴雨频率的增加以及蒸发量的下降强化了五河流量的增加趋势,由此可大致判定鄱阳湖流域气候变化与洪涝灾害之间可能存在的关系,这可为理解气候变化在该流域的响应和预测该流域未来可能的洪涝灾害提供依据.;Based on observed data of 14 meteorological stations and six main hydrological stations in lake Poyangbasin, the trends and jumps of temperature, precipitation, pan evaporation(PE), reference evapotranapiration(ETr) and discharge are analyzed from 1961 to 2003. The results indicate that the temperature jumped in 1990, then it dominated an upward trend ever since 1990. Significant positive trend was noticed after 1986 in winter. Asto precipitation, it changed abruptly in 1990. In 1992, the heavier rainstorm resulted in more precipitation in sum-mer. Significant negative trend of PE and ETr was found, especially in summer. It was found that summer ETr fellsharply after 1992. As for spatial distribution, significant climate change areas are found in the Raohe River basin,the Xinjiang River basin and the lower reaches of the Ganjiang River basin. The climate change trends above-men-tioned,that is coincident with the trend of the Yangtze River basin, are more obvious in 1990s. As a result, therunoff to the Lake Poyang also rose up. In 1990s, warm and humid climate tendency was strengthened. The climatechange of lake Poyang basin is much significant in the Yangtze River basin.

Silver Carp, Hypophthalmichthys molitrix, in the Poyang Lake belong to the Ganjiang River Population Rather than the Changjiang River Population

The Poyang Lake is the largest lake and the main nursery area in the middle basin of the Changjiang (Yangtze) River. We compared molecular genetic markers of silver carp among populations of the Changjiang River, the Ganjiang River and the Poyang Lake using the ND5/6 region of mtDNA. Analysis of restriction fragment length polymorphisms (RFLPs) of this region revealed distinct variation between the Ganjiang River and the Changjiang River populations. The Poyang Lake is linked with the Ganjiang River and the Changjiang River. Shared RFLP fragments between the Ganjiang River population and the Poyang Lake population are as high as 61.4%. The value is 47.74% between the populations of the Changjiang River and that of the Poyang Lake. Frequencies of bands peculiar to the Ganjiang River population are the same as in the Poyang Lake population. We conclude that the Poyang Lake silver carp population consists mainly of the Ganjiang River population. The water level of the Poyang Lake outlet, which is higher than that of the Changjiang River in the silver carp spawning season, supports this conclusion.