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1.
V. N. Mikhailov D. V. Magritsky V. I. Kravtsova M. V. Mikhailova M. V. Isupova 《Water Resources》2012,39(1):11-43
Regularities in the response of the mouths of major rivers, flowing into the Caspian Sea, to large-scale variations in its
level and river water runoff and sediment yield are considered. Changes in the morphological structure and hydrological regime
of the Volga, Terek, Sulak, Ural, and Kura mouths have been analyzed in both geological past and separately for three modern
periods: a considerable drop in Caspian Sea level before 1978, its abrupt rise in 1978–1995, and a relative stabilization
in the subsequent years. Specific features were identified in the hydrological-morphological processes in different mouths,
caused by the differences in river sediment yields, and the slopes of delta surface and mouth nearshore beds. Some theoretical
and methodological approaches were verified in the analysis and evaluation of the processes under consideration. The obtained
results of studies of the mouths of rivers flowing into the Caspian Sea can be regarded as examples and analogues in the assessment
of processes, which take place at the mouths of other Russian and world rivers at present and can take place in the future
under anticipated natural and anthropogenic variations in sea level and river runoff. 相似文献
2.
M. V. Mikhailova 《Water Resources》2006,33(5):523-534
Sediment balance at river mouths—a physical basis of delta dynamics—is considered. The specific features of relationships between sediment balance components at a mouth of a river are established for a stable, rising, or dropping sea level. The development of the delta of the Chilia branch at the Danube mouth is considered as an example of delta dynamics under the conditions of a relatively stable sea level. The evolution of the Sulak delta in the Caspian Sea with a highly variable level is considered as an example of delta dynamics in the case of a considerable rise and drop of water level in the water body. The anthropogenic reduction of sediment runoff of the rivers (by a factor of two in the Danube, and by a factor of nine in the Sulak) is taken into account. The relationship between the sediment runoff of a river and the volume of the “backwater prism” that formed due to sea level rise is shown to be the key factor in the development of delta in the case of sea level rise. In the case of a drop in the sea level, the relationship between the “active” and “passive” progradation of the delta into the sea is determined by the sediment runoff of the river, the rate of sea level drop, and the bed slope in the coastal area of the nearshore zone. 相似文献
3.
The evolution of the eastern part of the Terek mouth area in the period of the current rise of the Caspian Sea level has been traced by aerial and space photographs made at different times. With the help of computer processing of the photographs, a set of maps have been compiled including maps of the eastern part of the Terek delta (including the former Agrakhan Bay and the Agrakhan Peninsula with a new delta) in 1978, 1991, and 1997, as well as a map of its dynamics in the period of its most radical changes (1978–1991). The response of the coastal environment to the sea level rise has been analyzed, and the correctness of the forecasts of changes in the coastal zone has been evaluated. 相似文献
4.
General information on the Nile River basin is presented. Specific features of the morphological regime of the Nile Delta and its near-shore zone, as well as the delta water balance and groundwater regime are discussed. The dynamics of the sea coastline of the Nile Delta is described in great detail. It is shown that the recent delta of the Nile and its sea coastline have been formed under the joint impact of the eustatic sea level rise, subsidence of sediments in the northern part of the deltaic plain, and considerable decrease in the river sediment runoff after the construction of the Aswan High Dam. 相似文献
5.
Three areas with different trends in water level variations over the period of many years have been distinguished within the Kuban Delta. It was found that the eustatic level rise of the Sea of Azov and soil subsidence on the sea edge of the delta and in the lower reaches of the Protoka Branch were responsible for the noticeable rise in water levels. A considerable water level drop caused by the river runoff regulation and erosion of the lower pool of the Krasnodarskii Waterworks was recorded in the upper part of the delta; in the rest part of the delta, water levels dropped insignificantly, which was partially due to the impact of the tectonic uplift. 相似文献
6.
A probabilistic technique is developed for assessing water level in the mouth reach of the Ural River in the course of interaction between the river runoff and irregular rises in the Caspian Sea level (positive setups) at the predicted background sea levels of –26.5 and –26.0 m abs. 相似文献
7.
Water level variations in the Kiliya Branch of the Danube Delta over the period of 40 years (1958–1997) were analyzed. These level variations were subdivided into three components related to long-term variations of the share of the branch runoff and its redistribution within a year resulting from the Danube flow regulation; subsidence of deltaic deposits; and backup caused by the rising Black Sea level. It was revealed that, during the low-flow period, this backup had propagated to the river mouth at a distance of 160 km. 相似文献
8.
The peculiarities of the hydrological regime of the delta and near-shore zone of the Po River are discussed. The intrusion of salt seawater into the delta is described. The history of the Po Delta formation has been restored on the basis of the analysis of historical, archeological, and cartographic data. As shown, the peculiarities of hydrological and morphological processes in the Po River mouth are associated with natural and specifically with human-induced variations in sediment runoff of the river, with levee construction along branches, subsidence of deltaic deposits, and eustatic rise of the sea level. 相似文献
9.
Specific processes of delta formation at the Mississippi River mouth are discussed. In the last 7000–8000 years, a series
of large deltaic lobes was formed in succession at the Mississippi River mouth under the condition of high river sediment
runoff and stabilization of the ocean level after its sudden postglacial rise. In the mid-XX century, the formation of a new
deltaic lobe began at the Atchafalaya Branch mouth. Over the last centuries, the processes of delta formation at the Mississippi
River mouth slowed down as a result of the river sediment runoff decrease after flow regulation of the Missouri and Arkansas
tributaries; in some parts of the deltaic plain, these processes gave way to degradation of marshes and seashore erosion under
the impact of intense land subsidence. The current processes of delta formation are under the great influence of local economic
activities. 相似文献
10.
The development of the Sulak River Delta in the 19th and 20th centuries is discussed. It is shown that a drastic reduction in sediment runoff after the establishment of river flow regulation, anthropogenic restructuring of the river channel system in the delta area, and large-scale variations in the Caspian Sea level had an impact on the delta evolution. The processes of delta degradation over the period of the recent sea level rise are analyzed. The dynamics of the Sulak Delta in recent decades is studied using space photographs. 相似文献
11.
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
12.
SEDIMENT CARRYING CAPACITY OF SEA CURRENT AND THE TRAINING OF THE YELLOW RIVER MOUTH 总被引：1，自引：0，他引：1
LI Diankui 《国际泥沙研究》1999,(2)
1INTRODUCTIONTheYellowRivercarries1.6billiontonsofsedanmentload,rankedthefirstintheworld.Sedimentationinthelowerreachesresultedinfrequentlyshiftoftherivercourses.ThroughoutthehistoryofChina,theYellowRiverhasbeenassociatedwithfloodsandfamine,earningtherivername"China'ssorrow"(Hu,l996).Instabilityoftheriverchannel,especiallythedeltachannel,restraintstheeconomicdevelopmentofthearea.TheDongyingmunicipalgovernment,theShenliOilCorporationandtheYellowRiverMouthManagementBureauofYRCC(Yel… 相似文献
13.
Since the end of the post‐glacial sea level rise 6800 years ago, progradation of river mouths into estuaries has been a global phenomenon. The responses of upstream alluvial river reaches to this progradation have received little attention. Here, the links between river mouth progradation and Holocene valley aggradation are examined for the Macdonald and Tuross Rivers in south‐eastern Australia. Optical and radiocarbon dating of floodplain sediments indicates that since the mid‐Holocene sea level highstand 6800 years ago vertical floodplain aggradation along the two valleys has generally been consistent with the rate at which each river prograded into its estuary. This link between river mouth progradation and alluvial aggradation drove floodplain aggradation for many tens of kilometres upstream of the estuarine limits. Both rivers have abandoned their main Holocene floodplains over the last 2000 years and their channels have contracted. A regional shift to smaller floods is inferred to be responsible for this change, though a greater relative sea level fall experienced by the Macdonald River since the mid‐Holocene sea level highstand appears to have been an additional influence upon floodplain evolution in this valley. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
14.
The problem of assessment of sea level rise impact on the hydrological regime and morphological structure of river deltas
is discussed. Studies of the response of river deltas, which are among the most vulnerable natural objects, to the sea level
rise has become urgent because of the global climate warming and the associated acceleration of the World Ocean level rise.
Methods are described that can be used for the analysis, calculation, and prediction of sea level rise impact on submergence
of deltas, propagation of backwater from the sea tides, surges, and salt seawater intrusion. Special emphasis is given to
channel processes in delta branches, which accompany sea level rise, as well as to delta coastline erosion and flow redistribution
among branches. In the course of research, due consideration was taken of the experience gained in studying the response of
river deltas on the Caspian Sea coasts to the recent considerable level rise in this water body. 相似文献
15.
M. V. Isupova 《Water Resources》2008,35(6):615-634
Long-term water level variations in the Volga mouth area and the effect exerted on them by the river’s flow and the Caspian Sea’s level variations are considered. Quantitative relationships were identified between the mean annual water levels at different gages in the mouth and the sea level. A backwater component was isolated in the long-term variations in water level in the Volga mouth area. Relationships between the daily water levels in the mouth and the Caspian Sea’s level at fixed water flow in the delta apex are presented. The magnitude and the propagation distance of backwater from the sea into the delta are specified. The responses of the mouth areas of rivers emptying into the Caspian Sea to sea level variations in the past century are compared. 相似文献
16.
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
17.
云梦泽与荆江三角洲的历史变迁 总被引：18，自引：4，他引：14
本文通过对大量地质地貌、考古和文史资料的综合考证与分析,讨论了(1)云梦泽的形成、范围与兴衰历史;(2)荆江三角洲变迁的过程、阶段与特征;(3)荆江三角洲与洪涝灾害;(4)江湖历史变迁与问题思考等。 相似文献
18.
M. V. Mikhailova 《Water Resources》2011,38(4):438-452
General geographic features of the Thames River, its basin, and mouth area, consisting of the tidal mouth reach of the river,
a large estuary, and an open nearshore zone of the river mouth (the North Sea coastal zone) are discussed. The peculiarities
of river and sea hydrological factors responsible for the regime of the Thames River mouth area are described in detail. Characteristics
of the river water runoff were specified and supplemented by the data on the river inundations in the area of London. Particular
emphasis was placed on variations in the mean sea level in the area of the Thames River mouth as well as on specific features
of tides and storm surges in the area of the sea inlet into the estuary. Main regularities in the estuary evolution during
Holocene and present-day morphological processes in the Thames River mouth area were revealed. 相似文献
19.
Thanh Duc Dang Thomas A. Cochrane Mauricio E. Arias Pham Dang Tri Van Tonny T. de Vries 《水文研究》2016,30(21):3824-3838
The Mekong floodplains, which encompasses the region from Kratie Township in Central Cambodia to the Vietnamese East Sea, is a region of globally renown agricultural productivity and biodiversity. The construction of 135 dams across the Mekong basin and the development of delta‐based flood prevention systems have caused public concern given possible threats on the stability of agricultural and ecological systems in the floodplains. Mekong dams store water upstream and regulate flow seasonality, while in situ flood prevention systems re‐distribute water retention capacity in the floodplains. The main aim of this paper is to evaluate possible impacts of the recent development of both hydropower dams and flood prevention systems on hydrological regimes in the Mekong floodplains. An analysis of measured daily and hourly water level data for key stations in the Mekong floodplains from Kratie to the river mouth in Vietnam was conducted. Hydropower dam information was obtained from the hydropower database managed by the Mekong River Commission, and the MODIS satellite imagery was used to detect changes in flooding extent related to the operation of flood prevention systems in the Vietnam Mekong Delta. Results indicate that the upper part of the floodplains, the Cambodian floodplains, may buffer upstream dam impacts to the Vietnam Mekong Delta. Flood prevention up to date has had the greatest effect on the natural hydrological regime of the Mekong floodplains, evidenced by a significant increase of water level rise and fall rates in the upper delta and causing water levels in the middle delta to increase. The development of flood prevention systems has also effected spatial distribution of flooding as indicated via a time series analysis of satellite imagery. While this development leads to increase localized agricultural productivity, our historical data analysis indicates that development of one region detrimentally affects other regions within the delta, which could increase the risk of future conflicts among regions, economic sectors and the ecological value of these important floodplains. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
20.
M. V. Mikhailova 《Water Resources》2010,37(2):160-171
The peculiarities of the hydrological regime of the Orinoco River and the coastal zone of the Atlantic Ocean that affect the
hydrological-morphological processes in the mouth area of the Orinoco River are considered. The major features of the delta
water regime, including its inundation, runoff distribution over the delta branches, water and sediment balance, and the processes
of river and sea water mixing are described. Special attention is paid to the morphological processes at the Orinoco mouth
(delta evolution and modern processes at its coastline). 相似文献