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1.
Qiang Zhang Yongqin David Chen Tao Jiang Xiaohong Chen Zufa Liu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(7):1001-1011
Sound understanding of hydrological alterations and the underlying causes means too much for the water resource management
in the Pearl River Delta. Incision of river channels plays the key role in the hydrological alterations. As for the causes
behind the river channel incision, sand dredging within the river network of the Pearl River Delta is usually assumed to play
the overwhelming role in changes of geometric shapes of the river channels. Based on thorough analysis of well-collected data
of channel geometry, streamflow, sediment load and water level, this study exposes new findings, investigating possible underlying
causes behind the changes of the geometric shapes of the river channels at the Sanshui and Makou station. The results of this
study indicate: (1) different changing properties of the geometric shapes are identified at the Sanshui and Makou stations.
Larger magnitude of changes can be found in the river channel geometry of the cross section at the Sanshui station when compared
to that at the Makou station. Lower water level due to fast riverbed downcutting at the Sanshui station than that at the Makou
station is the major reason why the reallocation of streamflow occurred and hence the hydrological alterations over the Pearl
River Delta; (2) depletion of sediment load as a result of construction of water reservoirs in the middle and upper Pearl
River basin, sand dredging mainly in the Pearl River Delta and heavy floods all contribute much to the incision or deposition
of the riverbed. Regulations of erosion and siltation process of the river channel often alleviate the incision of the river
channels after a relatively long time span, and which makes it even harder to differentiate the factors causing the river
channel incision; (3) the intensifying urbanization in the lower Pearl River basin greatly alters the underlying surface properties,
which has the potential to shorten the recession of the flood event and may cause serious scouring processes and this role
of flash floods in the incision of the river channels can not be ignored. This study is of great scientific and practical
merits in improving human understanding of regulations of river channels and associated consequences with respect to hydrological
alterations and water resource management, particularly in the economically booming region of China. 相似文献
2.
Abstract The Pearl River Delta (PRD) is a complicated criss-cross river network. The booming economy and intensifying human activity have greatly altered the natural water levels, which threatens regional sustainable development. The Mann-Kendall trend test and the kriging interpolation method were used to detect the spatial and temporal patterns in the trends of extreme high/low water levels related to different magnitudes of streamflow, in order to explore the impacts of hydrological processes on the water-level changes throughout the PRD. The results indicate that: (a) streamflow changes at the Sanshui and Makou stations exhibit different characteristics. No significant trend can be identified in the streamflow changes at Makou station; however, the streamflow at Sanshui station shows a significant increasing trend, especially in low-flow periods. The decreasing Makou/Sanshui streamflow ratio exerts tremendous impacts on the water-level changes in the hinterland of the PRD region. (b) Extreme high/low water levels exhibit similar changing patterns. The extreme high/low water levels in the high/normal flow periods are decreasing in both the upper PRD and the hinterland of the PRD region. Increasing extreme high/low water levels in low-flow periods can be identified in the hinterland of the PRD region. The coastal regions are characterized by increasing extreme high/low water levels. (c) Extreme high/low water levels for high/normal flow periods in the hinterland of the PRD are heavily impacted by topographic changes due to in-channel dredging. Increasing extreme high/low water levels along the coastal regions are mainly backwater effects caused by serious siltation and rising sea level. This study has scientific and practical merits in regional fluvial management and mitigation of natural hazards. Citation Zhang, Q., Xu, C.-Y. & Chen, Y. D. (2010) Variability of water levels and impacts from streamflow changes and human activity within the Pearl River Delta, China. Hydrol. Sci. J. 55(4), 512–525. 相似文献
3.
Wavelet-based characterization of water level behaviors in the Pearl River estuary, China 总被引:1,自引:0,他引:1
Qiang Zhang Chong-Yu Xu Yongqin David Chen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(1):81-92
In this paper, we analyzed the high/low water levels of eight stations along the Pearl River estuary and the high/low tidal
levels of Sanzao station, and streamflow series of Sanshui and Makou stations using wavelet transform technique and correlation
analysis method. The behaviors of high/low water levels of the Pearl River estuary, possible impacts of hydrological processes
of the upper Pearl River Delta and astronomical tidal fluctuations were investigated. The results indicate that: (1) the streamflow
variability of Sanshui and Makou stations is characterized by 1-year period; 1-, 0.5- and 0.25-year periods can be detected
in the high tidal level series of Sanzao station, which reflect the fluctuations of astronomical tidal levels. The low tidal
level series of Sanzao station has two periodicity elements, i.e. 0.5- and 0.25-year periods; (2) different periodicity properties
have been revealed: the periods of high water levels of the Pearl River estuary are characterized by 1-, 0.5- and 0.25-year
periods; and 1-year period is the major period in the low water levels of the Pearl River estuary; (3) periodicity properties
indicate that behaviors of low water levels are mainly influenced by hydrological processes of the upper Pearl River Delta.
High water levels of the Pearl River estuary seem to be affected by both hydrological processes and fluctuations of astronomical
tidal levels represented by tidal level changes of Sanzao station. Correlation analysis results further corroborate this conclusion;
(4) slight differences can be observed in wavelet transform patterns and properties of relationships between high/low water
levels and streamflow changes. This can be formulated by altered hydrodynamic and morphodynamic processes due to intensifying
human activities such as construction of engineering infrastructures and land reclamation. 相似文献
4.
Yongqin David Chen Qiang Zhang Xiaohong Chen Ping Wang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(2):235-246
The Pearl River basin bears the heavy responsibility for the water supply for the neighboring cities such as Macau, Hong Kong
and others. Therefore, effective water resource management is crucial for sustainable use of water resource. However, good
knowledge of changing properties of streamflow changes is the first step into the effective water resource management. With
this in mind, stability and variability of streamflow changes in the Pearl River basin is thoroughly analyzed based on monthly
streamflow data covering last half century using Mann–Kendall trend test and scanning t- and F-test techniques. The results indicate: (1) significant increasing monthly streamflow is observed mainly in January–April,
June and October–December. Monthly streamflow during May–September is in not significant changes. Besides, stations characterized
by significant monthly streamflow changes are located in the middle and the lower Pearl River basin; (2) changing points of
monthly streamflow series are detected mainly during mid-1960s, early 1970s, mid-1970s, early 1980s and early 1990s and these
periods are roughly in good agreement with those of annual, winter and summer precipitation across the Pearl River basin,
implying tremendous influences of precipitation changes on streamflow variations; (3) abrupt behaviors tend to be ambiguous
from the upper to the lower Pearl River basin, which should be due to enhancing combined effects of abrupt changes of precipitation.
The streamflow comes to be lower stability in recent decades. However, high stability of streamflow changes are observed at
hydrological stations in the lower Pearl River basin. The results of this study will be of great scientific and practical
merits in terms of effective water resource management in the Pearl River basin under the influences of climate changes and
human activities. 相似文献
5.
The effects of dam construction and precipitation variability on hydrologic alteration in the Lancang River Basin of southwest China 总被引:4,自引:2,他引:2
Qinghe Zhao Shiliang Liu Li Deng Shikui Dong Juejie Yang Cong Wang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(7):993-1011
This paper presents an evaluation of the spatio-temporal patterns of hydrologic alteration induced by dam construction and precipitation variability in the Lancang River Basin of southwest China from 1957 to 2000. Analyses were conducted using the linear regression method, the Mann–Kendall test, and the Range of Variability Approach. The results indicate that there was considerable variation in the average monthly precipitation between the pre- and post-dam periods in the Lancang River Basin. Second, the magnitude of monthly runoff was strongly related to precipitation, which showed an up-down annual variation, and was significantly altered by dam construction and precipitation variability. In the modified series (hydrologic series with the precipitation impacts removed), runoff deviations between the pre- and post-dam periods became larger. Third, the extreme runoff cycles were influenced by dam construction and precipitation variability downstream from the dam, and the monthly maximum runoff increased from the pre-dam to post-dam period at all hydrologic stations. Fourth, the degree of hydrologic alteration (DHA) indicates that the precipitation variability not only affected the hydrologic regime of unregulated river reach but also modified the negative impacts of dam construction, which could provide a modest mitigation of the hydrologic alterations induced by dam construction, possibly decreasing the level of DHA. Last, the overall degree of hydrologic alteration in the observed series reached 25.2, 25.3, and 29.1 % for the upstream, midstream, and downstream areas, respectively. These results show that the hydrologic regimes of the Lancang River during the 1957–2000 period were affected by damming and precipitation variability, but the hydrologic alteration was relatively low in the upstream areas of the river without a dam. 相似文献
6.
Changing properties of precipitation concentration in the Pearl River basin, China 总被引:16,自引:3,他引:13
Qiang Zhang Chong-yu Xu Marco Gemmer Yongqin David Chen Chunling Liu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(3):377-385
In this paper, precipitation concentrations across the Pearl River basin and the associated spatial patterns are analyzed
based on daily precipitation data of 42 rain gauging stations during the period 1960–2005. Regions characterized by the different
changing properties of precipitation concentration index (CI) are identified. The southwest and northeast parts of the Pearl
River basin are characterized by lower and decreasing precipitation CI; the northwest and south parts of the study river basin
show higher and increasing precipitation CI. Higher but decreasing precipitations CI are found in the West and East River
basin. Comparison of precipitation CI trends before and after 1990 shows that most parts of the Pearl River basin are characterized
by increasing precipitation CI after 1990. Decreasing precipitation CI after 1990 (compared to precipitation CI changes before
1990) is observed only in a few stations located in the lower Gui River and the lower Yu River. Significant increasing precipitation
CI after 1990 is detected in the West River, lower North River and upper Beipan River. These changes of precipitation CI in
the Pearl River basin are likely to be associated with the consequences of the well-evidenced global warming. These findings
can contribute to basin-scale water resource management and conservation of ecological environment in the Pearl River basin. 相似文献
7.
Recent changes in the sediment regime of the Pearl River (South China): Causes and implications for the Pearl River Delta 总被引:1,自引:0,他引:1 下载免费PDF全文
Riverine sediments have played an important role in the morphological evolution of river channels and river deltas. However, the sediment regime in the many world's rivers has been altered in the context of global changes. In this study, temporal changes in the sediment regime of the Pearl River were examined at different time scales, that is, annual, seasonal, and monthly time scales, using the Mann–Kendall test. The results revealed that precipitation variability was responsible for monthly and seasonal distribution patterns of the sediment regime and the long‐term changes in the water discharge; however, dam operation has smoothed the seasonal distribution of water discharge and resulted in decreasing trends in the annual, wet‐season, and dry‐season sediment load series since the 1950s. Due to the different regulation magnitudes of dam operation, differences were observed in sediment regime changes among the three tributaries. In addition, human activities have altered the hysteresis of seasonal rating curves and affected hysteresis differences between increasing and decreasing water discharge stages. Sediment supply is an important factor controlling river channel dynamics, affecting channel morphology. From the 1950s to the 1980s, siltation was dominant in river channels across the West River and North River deltas in response to the sediment increases; however, scouring occurred in the East River deltas due to sediment reduction. Significant erosion occurred in river channels in the 1990s, which was mostly due to downcutting of the river bed caused by sand excavations and partly because of the reduced sediment load from upstream. Although sand excavations have been banned and controlled by authority agencies since 2000, the erosion of cross sections was still observed in the 2000s because of reduced sediment caused by dam construction. Our study examines the different effects of human activities on the sediment regime and downstream channel morphology, which is of substantial scientific importance for river management. 相似文献
8.
溶解氧是水生生态系统健康程度的重要度量指标,研究溶解氧时空变化及其影响因素对揭示河流溶解氧动态过程和理解水体生物地球化学循环具有重要意义. 当前,许多河流均存在溶解氧偏低问题,严重影响河流水质. 基于此,收集了珠江流域东江(东莞段)上游桥头、中游樟村和下游沙田泗盛3个水质监测站的实测资料,采用折线图和箱型图分析溶解氧在月、季节和年际时间尺度下的变化规律及其空间差异; 采用最大信息系数、交叉小波转换和多元线性回归3种方法解析溶解氧时空变化的影响因素. 结果表明:空间分布上,溶解氧浓度从上游到下游逐渐降低,低值区分布在入海口处的沙田泗盛站,多年平均溶解氧浓度仅为3.11 mg/L. 时间变化上,2011—2019年溶解氧主要在11.64个月的周期下循环变化. 溶解氧展现出明显的季节性. 3个站点丰水期溶解氧浓度比枯水期分别降低1.68、2.03和1.77 mg/L. 驱动因素上,溶解氧的时空变化受到多个因素的综合作用. 桥头站和樟村站水质较好,水温是这两个站点溶解氧时空变化的主要影响因素. 其主要在8~16个月的周期上调控溶解氧变化,在两个站点分别可以解释溶解氧整体变化的70%和57%. 沙田泗盛站受多条支流汇入的影响,水体中硝化和氧化作用耗氧增强,加之悬浮物遮光效应,使得该处的溶解氧浓度降低. 相似文献
9.
This paper examines present and future resource utilization in the tidal section of the Georges River in the southern part of Sydney. Over the last 30 years, the physical characteristics of the river have changed as a result of urbanization, changed hydrologic regime and sand dredging. Urbanization has resulted in an increase in population from 190,000 in 1947 to 550,000. This has resulted in an increase in runoff, sediment input to the river and waste disposal. The change in hydrologic regime has resulted in a substantial increase in the magnitude and frequency of flooding which has increased erosion. Sand dredging has increased the channel capacity, enlarged the tidal prism and increased water turbidity. It has also resulted in extensive bank erosion in the upper part of the river and extensive deposition lower down as tailings are deposited. Although most of these changes have resulted in the deterioration of environmental quality, use of the river for recreation and as an urban amenity has increased. 相似文献
10.
Changing properties of hydrological extremes in south China: natural variations or human influences?
Extreme events are drawing increasing concerns in recent decades due to their catastrophic nature. In this case, we thoroughly analysed the statistical behaviours of hydrological extremes in the south China by taking Guangdong province as a case study because of its unshakable position in the economic development in China. Our results further corroborated the fact that the hydrological changes are the integrated consequences of various external factors, basically the human activities and climate changes. Generally, decreasing annual maximum water (AMW) level was observed mainly in the seaward regions characterized by decreasing occurrence frequency of higher AMW level. Streamflow variations are influenced mainly by precipitation changes. Increasing annual maximum streamflow (AMS) can be attributed to the increasing precipitation intensity in recent years. However, in the East River basin, hydrological regulation function of the water reservoirs greatly reduced the AMS. In the lower East River, however, downcutting river channel and notable increases in the cross‐section area caused larger magnitude of decrease in AMW level when compared to AMS. The time when the relations between AMW level and streamflow start to change matches well the time when massive in‐channel sand dredging occurred, showing tremendous influences of human activities on hydrological processes in the lower Pearl River basin. This study will be of great scientific and practical merits in better understanding the statistical behaviours of hydrological extremes under the changing environment and also help to improve human mitigation to natural hazards in south China. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
11.
M. V. Mikhailova 《Water Resources》2011,38(3):284-297
The main regularities in the interaction of tides and storm surges at river mouths are discussed. A study of the Elbe River
mouth area is used to describe the processes of interaction of the eustatic sea level rise, tides, surges, and river flow
and special features of formation of maximum water levels. As shown, the intensification of cyclonic activity over the Northern
Atlantic in the second half of the XX century resulted in more frequent extremely high storm surges at the Elbe River mouth.
An assessment is given for possible changes in the regime of tides and surges at the Elbe River mouth in the XXI century,
which may be caused by the acceleration of the eustatic sea level rise. The impact of local hydraulic engineering works (diking,
dredging, and channel straightening) on maximum water levels within the town of Hamburg is analyzed. 相似文献
12.
13.
Precipitation change and human impacts on hydrologic variables in Zhengshui River Basin, China 总被引:4,自引:3,他引:1
Juan Du Fei He Zhao Zhang Peijun Shi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(7):1013-1025
Climate change and anthropogenic impacts on hydrologic variables have received significant attention in recent years. We assessed
stream flow and water level in the Zhengshui River basin, China, in the period 1960 to 2003 in response to precipitation variation
and anthropogenic factors. Analyses of daily discharge and water level records, and derived annual, seasonal and monthly series,
showed that Zhengshui River flows had a significant increasing trend, with an abrupt change point in 1990. There was a significant
decreasing water level trend with an abrupt change point in 1995. Human activities and precipitation contributed 53 and 47%,
respectively, to increase in stream flow during 1991–2003. Anthropogenic activities such as sand dredging, dominated the decrease
in water level during 1994–2003. Human-induced land use change, soil erosion and sand excavation driven by rapid economic
development have played a more important role than precipitation variation in hydrological changes in the Zhengshui River
basin over the past 50 years. 相似文献
14.
15.
Risks posed by trace organic contaminants in coastal sediments in the Pearl River Delta, China 总被引:8,自引:0,他引:8
Fung CN Zheng GJ Connell DW Zhang X Wong HL Giesy JP Fang Z Lam PK 《Marine pollution bulletin》2005,50(10):1036-1049
Local marine environments in China's Pearl River Delta (PRD), the most rapidly developing region in one of the world's fastest growing economies, have been experiencing significant environmental stress during the past decades. This investigation was conducted to determine the status and trends of persistence organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and dioxin-related compounds in marine sediments collected from sixteen coastal stations in the Pearl River Delta (PRD) in March 2003. Elevated concentrations of PAHs (94-4300 ng/g), PCBs (6.0-290 ng/g), PHCs (14-150 microg/g), and DDTs (1.4-600 ng/g) were detected in sediment samples. In addition, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like activities in the sediment samples were estimated to range from 0.3 to 440 pg TCDD-EQ/g. Sediments collected from Xiashan contained the greatest concentrations of trace organic contaminations amongst all the sampling stations in the present study. The degree of trace organic contamination was, in general, more severe at stations situated along the west shores of the PRD than their counterparts in the east. A preliminary assessment was performed to examine the probable risks to the marine ecosystem due to POPs. The results showed that OC pesticide contamination in the PRD was particularly serious and might pose a threat to the health of the marine inhabitants. 相似文献
16.
Investigating the changes in streamflow regimes in response to various influencing factors contributes to our understanding of the mechanisms of hydrological processes in different watersheds and to water resource management strategies. This study examined streamflow regime changes by applying the indicators of hydrologic alteration method and eco-flow metrics to daily runoff data (1965–2016) from the Sandu, Hulu and Dali Rivers on the Chinese Loess Plateau, and then determined their responses to terracing, afforestation and damming. The Budyko water balance equation and the double mass curve method were used to separate the impacts of climate change and human activities on the mean discharge changes. The results showed that the terraced and dammed watersheds exhibited significant decreases in annual runoff. All hydrologic metrics indicated that the highest degree of hydrologic alteration was in the Sandu River watershed (terraced), where the monthly and extreme flows reduced significantly. In contrast, the annual eco-deficit increased significantly, indicating the highest reduction in streamflow among the three watersheds. The regulation of dams and reservoirs in the Dali River watershed has altered the flow regime, and obvious decreases in the maximum flow and slight increases in the minimum flow and baseflow indices were observed. In the Hulu River watershed (afforested), the monthly flow and extreme flows decreased slightly and were categorized as low-degree alteration, indicating that the long-term delayed effects of afforestation on hydrological processes. The magnitude of the eco-flow metrics varied with the alteration of annual precipitation. Climate change contributed 67.47% to the runoff reduction in the Hulu River watershed, while human activities played predominant roles in reducing runoff in the Sandu and Dali River watersheds. The findings revealed distinct patterns and causes of streamflow regime alteration due to different conservation measures, emphasizing the need to optimize the spatial allocation of measures to control soil erosion and utilize water resources on the Loess Plateau. 相似文献
17.
Comparison of evapotranspiration variations between the Yellow River and Pearl River basin, China 总被引:6,自引:3,他引:3
Qiang Zhang Chong-Yu Xu Yongqin David Chen Liliang Ren 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(2):139-150
Based on daily meteorological data at 43 gauging stations in the Pearl River basin and 65 gauging stations in the Yellow River
basin, we analyze changing properties of actual evapotranspiration (ETa), reference evapotranspiration (ETref) and precipitation in these two river basins. In our study, Pearl River basin is taken as the ‘energy-limited’ system and
the Yellow River basin as the ‘water-limited’ system. The results indicate decreasing ETa in the Pearl River and Yellow River basin. However, different changing properties are detected for ETref when compared to ETa. The middle and upper Yellow River basin are characterized by increasing ETref values, whereas the Pearl River basin is dominated by decreasing ETref values. This result demonstrates enhancing drying force in the Yellow River basin. ETa depends mainly on the changes of precipitation amount in the Yellow River basin. In the Pearl River basin, however, ETa changes are similar to those of ETref, i.e. both are in decreasing trend and which may imply weakening hydrological cycle in the Pearl River basin. Different influencing
factors are identified behind the ETa and ETref in the Pearl River and Yellow River basin: In the Pearl River basin, intensifying urbanization and increasing aerosol may
contribute much to the evapotranspiration changes. Variations of precipitation amount may largely impact the spatial and temporal
patterns of ETa in the Yellow River basin. The current study is practically and scientifically significant for regional assessment of water
resource in the arid and humid regions of China under the changing climate. 相似文献
18.
Quanxi XU Songsheng CHEN Ming XIONG Shengwei LI Zefang CHEN 《国际泥沙研究》2007,22(3):228-237
The Jialingjiang River basin is one of the main sediment contributing areas in the upper reaches of the Changjiang River. Great changes have taken place in the runoff and sediment discharge in recent years. Comparing the data of 1991-2003 with the data of 1954-1990, the annual runoff of the Jialingjiang River basin decreased by 23 %, and the suspended sediment transport decreased by 74% or 105 million tons. The main factors affecting the reduction include a decrease in rainfall, sediment detention of hydraulic structures, soil and water conservation activities, sedimentation and sand dredging in the river channel. Thorough investigation and analysis of the contribution of each factor to the sediment decrease at Beibei Station was determined for the first time. The following are the contributing percentages for each factor: a decrease in runoff accounted for 32.9%; soil and water conservation measures accounted for 16.4%; sediment detention of hydraulic structures accounted for 30.5%; sedimentation, river channel sand dredging, and other factors accounted for 20.2%. These findings are very important for forecasting the trend of inflow sediment discharge variation. 相似文献
19.
Influence of Three Gorges Dam on streamflow and sediment load of the middle Yangtze River, China 总被引:2,自引:2,他引:0
Qiang Zhang Vijay P. Singh Xiaohong Chen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(4):569-579
Using updated hydrological datasets from three stations, including Cuntan, Yichang and Hankou, covering the period of January
1992–December 2008, the influence of Three Gorges Dam (TGD) on streamflow and sediment load of the Yangtze River was investigated.
Results indicated that TGD did not seem to exert a significant influence on streamflow occurring at three stations and changes
in streamflow can be mainly attributed to streamflows of tributaries. However, a sharp decrease in the sediment load after
the impoundment of TGD was observed. Clear water after the impoundment caused erosion of riverbed and resulted in more sediment
at the Hankou station than at the Yichang station. No distinct changes in the annual and monthly maximum sediment loads were
observed before and after the impoundment. Therefore, annual and monthly maximum sediment load changes should be subjected
mainly to river hydraulics. This study has practical relevance for understanding the influence of large hydraulic structures
on the hydrological processes of large rivers. 相似文献
20.
Hydrological and morphological processes in the Zhujiang River (Pearl River) mouth area of China are discussed. The hydrological regime of the Xijiang River, which is the largest river of South China and the main source of water inflow into the Zhujiang mouth area, is described. The basic features of the hydrological regime of the delta and the near-shore zone of the Zhujiang River mouth are characterized, much attention being given to the role of tides and mixing of river and sea water in the hydrological regime. Special emphasis is placed on morphodynamic processes at the mouth area and the history of the Zhujiang Delta evolution. 相似文献