scholarly journals Long-Term (1986–2018) Evolution of Channel Bars in Response to Combined Effects of Cascade Reservoirs in the Middle Reaches of the Hanjiang River

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 136 ◽  
Author(s):  
Yingying Zhang ◽  
Xiaobin Cai ◽  
Chao Yang ◽  
Enhua Li ◽  
Xinxin Song ◽  
...  
Keyword(s):  
Water Level ◽  
Water Conservation ◽  
Hydrological Regime ◽  
High Water ◽  
Combined Effects ◽  
Strong Negative Correlation ◽  
Cascade Reservoirs ◽  
Hanjiang River ◽  
Over Exploitation ◽  
Channel Bar

Channel bars are essential landforms and their evolution is crucial to aquatic and riparian biodiversity, river’s water-sediment process, and economic development. With the development of water conservation facilities and hydropower projects, numerous changes have been taken place in hydrological regimes and morphology. There have been many changes on channel bars in the middle reaches of Hanjiang River due to the combined effects of cascade reservoirs. However, little was known about such dynamics and their linkages to cascade dams across the entire downstream area. Using Landsat remote sensing images from 1986–2018 and the threshold binary Otsu extraction method, this study completed comprehensive monitoring of nine mid-channel bars (DX1–DX7, XZ1, and XZ2), and three shoal group (XZ3–XZ5) dynamics. Results showed that the mid-channel bars’ area in the reach from Danjiangkou to Xiangyang (DX) decreased over the past 33 years, with the exception of DX4, while the total area decreased by 23.19%, this channel bars’ area change was mainly influenced by backwater from the Cuijiaying Reservoir with high water level after 2010 (r = −0.93, p < 0.01). The total channel bar area from Xiangyang to Huangzhuang (XZ) decreased by 16.63% from 1986 to 2018. The total channel bar area in XZ had a strong negative correlation with runoff at Huangzhuang hydrologic station (r = −0.79, p < 0.05), which was partly attributed to upstream precipitation according to the high correlation between runoff and precipitation (R2 = 0.65). In general, the DX section was under equilibrium between scouring and deposition compared to downstream Xiangyang, the bars in DX section were mainly affected by water level, and bars in XZ section during 1986–2018 were complicated because it was upstream eroded and downstream deposited. In addition, vegetation cover, revetments, flood events, sand mining, land use, and over-exploitation may cause channel bar area dynamics. Hence, more continuous investigations are suggested to focus on effects of cascade reservoir operation on hydrological regime, as well as the changing morphology of channel bars in the middle reaches of the Hanjiang River.

scholarly journals The Current Situation at the Argun River Boundary Reach

2018 ◽  
Author(s):  
Keyword(s):  
Water Level ◽  
Vegetation Index ◽  
Hydrological Regime ◽  
Radical Change ◽  
High Water ◽  
High Rate ◽  
Floodplain Vegetation ◽  
Water Level Rise ◽  
Volume Of Transfer ◽  
Cyclic Changes

Water/economic problems and the current changes in the Argun River boundary reach hydrological regime have been analyzed. The Russian-Chinese boundary coincides with the 951 km long reach of the Argun River. In the upper part of this reach there are no tributaries to the Argun so the water regime is completely determined by the runoff from the territory of China. High rate of rise of the neighboring regions of China resulted in the shortage of water resources and a number of environmental problems. Various water/economic measures are taken on the territory of China in order to solve these problems. Diversion of the part of the Khailar River (the Argun River upstream) runoff to the Lake Dalaynor (Khulun) should be specially mentioned. The Lake Dalaynor is sublecte to the water level cyclic changes. The last low-water period started in 1999 and the level lowering was 4.6 m by 2009. The transfer of the part of the Khailar River runoff started in 2009 and over the past period the water level in the lake became 3.5 m higher. The water level rise is observed only in high-water years while during the other periods all the volume of transfer is spent to evaporation. The runoff transfer caused the radical change of the Argun hydrological regime: the lowwater flow demonstrated the 3-5 times decrease, the floodplain flooding recurrence and duration also decreased. The vegetation index (EVI) downstream the transfer canal is an evidence of the floodplain vegetation suppression as a result of water availability decrease. Indices of the Argun River water quality at the starting section of the boundary reach are the worst in the region.

scholarly journals Dynamics of plankton biocenoses under water level fluctuations in steppe lakes

2022 ◽  
Vol 962 (1) ◽  
pp. 012002
Author(s):  
E Yu Afonina ◽  
N A Tashlykova
Keyword(s):  
Water Level ◽  
Green Algae ◽  
Hydrological Regime ◽  
Steppe Zone ◽  
High Water ◽  
Water Level Fluctuations ◽  
Water Level Variation ◽  
Arid Steppe ◽  
Filling Phase

Abstract Barun-Torey and Zun-Torey lakes are located in the arid steppe zone of the Central (Inner) Asia, Eastern Siberia, Russia. The Torey lakes are characterizes unstable hydrological regime. The water level variation is explained by the periodic filling and drying of the lakes due to cyclical climatic changes in humidity and temperature. We conducted our studies various water level phases of the climatic cycle: from high water level (1999, 2003) to drying out and the initial filling phase (2007, 2011, 2014, 2016, 2018, and 2020). The aim of this paper is to present long-term research results on changes in the plankton biocenoses of the Torey lakes during a climate cycle, the drying and initial filling of basins. Succession of plankton dominant species is in the direction of: diatoms+green algae and rotifers+crustaceans → green algae and crustaceans → green algae+cyanobacteria and crustaceans → no planktonic algae and invertebrates → cyanobacteria+diatoms+green algae and rotifers+cladocerans+copepods.

CRITICAL FACTORS OF WATER CONTENT FOR FISH STOCKS IN THE WATER RESERVOIRS OF KAZAKHSTAN

2017 ◽  
pp. 9-18
Author(s):  
Saule Zhangirovna Asylbekova ◽  
Kuanysh Baibulatovich Isbekov ◽  
Evgeniy Vyacheslavovich Kulikov
Keyword(s):  
Water Content ◽  
Water Level ◽  
Water Availability ◽  
Hydrological Regime ◽  
Fishing Effort ◽  
Water Reservoirs ◽  
The Caspian Sea ◽  
Annual Fish ◽  
Commercial Fish ◽  
Fish Stocks

The hydrological regime of water reservoirs in different years has a decisive impact on the abundance of commercial fish stocks and the quality of ichthyocenoses. In this connection in 2015-2016 there was conducted a retrospective analysis and ranking of hydrological regime impact on these factors. The paper gives evaluation of catches and fish stocks under different scenarios of water availability in the main fishing ponds of the Republic of Kazakhstan that give about 80% of the annual fish catch of the country (except the Caspian Sea). There were analyzed 2000 factors of hydrological regime (water level, annual discharge) and 1845 factors of fishing stocks (catches, abundance, fish biomass). The paper determines the critical characteristics of water availability for fish stocks. There have been proposed a number of administrative decisions and actions in case if water content would approach to the critical level. Among them: limitation of fish catches in the following year; widening zones restricted for fishing; intensification of safety measures of the fish young in residual ponds during arid periods; introduction of catch standards for a unit of fishing effort in low-water years, high-water years and years with normal water level in rivers.

HYDROLOGICAL REGIME AND FREEZING OF HUMMOCKY BOGS ON THE EUROPEAN NORTH OF RUSSIA

2019 ◽  
Vol 12 (9-10) ◽  
pp. 38-48
Author(s):  
V. I. Batuev ◽  
I. L. Kalyuzhny
Keyword(s):  
Water Level ◽  
Hydrological Regime ◽  
Average Intensity ◽  
Water Level Rise ◽  
Northern European ◽  
European North ◽  
Bog Waters ◽  
Northern European Russia ◽  
Seasonal Thawing ◽  
First Time

The development of the European North of Russia, where flat and high-hummocky bog complexes are spread, requires information on the processes of formation of their hydrological regime and freezing of this territory. For the first time, based on observational data, for the period from 1993 to 2013, characteristics of the hydrological regime and freezing of hummocky bogs in Northern European Russia are presented, the case study of the Lovozerskoye bog. The observations were carried out in accordance with the unified methods, approved for the specialized network of Roshydromet bog stations. The regularities of the formation of the hydrological regime of hummocky bogs have been revealed: bog water level drops dramatically from the beginning of freezing to the end of March, rises during snow melt period, slightly drops in summer and rises in autumn. The main feature of hummocky bogs is permafrost, which determines their specific structure. It has been discovered that gravitation snowmelt and liquid precipitation waters relatively quickly run down the hummocks over the frozen layer into hollows between them. Levels of bog waters on the hummocks are absent for a longer period of time. In spring, the amplitude of water level rise in swamplands is on average 60–80 cm. Air temperature and insulation properties of snow are the main factors that influence the bog freezing. Hummocks freeze out as deep as 63–65 cm, which corresponds to the depth of their seasonal thawing in the warm period of the year, and adjoin the permafrost. The greatest depth of freezing of the swamplands is 82 – 87 cm, with an average of 68 cm. The frozen layer at swamplands thaws out from both its upper and bottom sides. The melting of the frozen layer at hummocks occurs only from the bog surface with an average intensity of 0,51 cm/day.

Lake and inland dunes as interconnected Systems: The story of Lake Tresssee and an adjacent dune field (Schleswig-Holstein, North Germany)

The Holocene ◽  
2020 ◽  
pp. 095968362098168
Author(s):  
Christian Stolz ◽  
Magdalena Suchora ◽  
Irena A Pidek ◽  
Alexander Fülling
Keyword(s):  
Water Level ◽  
Bronze Age ◽  
Environmental Changes ◽  
High Water ◽  
Alluvial Fan ◽  
Water Levels ◽  
Lake Area ◽  
Dune Field ◽  
The North ◽  
Sand Drift

The specific aim of the study was to investigate how four adjacent geomorphological systems – a lake, a dune field, a small alluvial fan and a slope system – responded to the same impacts. Lake Tresssee is a shallow lake in the North of Germany (Schleswig-Holstein). During the Holocene, the lake’s water surface declined drastically, predominately as a consequence of human impact. The adjacent inland dune field shows several traces of former sand drift events. Using 30 new radiocarbon ages and the results of 16 OSL samples, this study aims to create a new timeline tracing the interaction between lake and dunes, as well, as how both the lake and the dunes reacted to environmental changes. The water level of the lake is presumed to have peaked during the period before the Younger Dryas (YD; start at 10.73 ka BC). After the Boreal period (OSL age 8050 ± 690 BC) the level must have undergone fluctuations triggered by climatic events and the first human influences. The last demonstrable high water level was during the Late Bronze Age (1003–844 cal. BC). The first to the 9th century AD saw slightly shrinking water levels, and more significant ones thereafter. In the 19th century, the lake area was artificially reduced to a minimum by the human population. In the dunes, a total of seven different phases of sand drift were demonstrated for the last 13,000 years. It is one of the most precisely dated inland-dune chronologies of Central Europe. The small alluvial fan took shape mainly between the 13th and 17th centuries AD. After 1700 cal. BC (Middle Bronze Age), and again during the sixth and seventh centuries AD, we find enhanced slope activity with the formation of Holocene colluvia.

scholarly journals Long-term changes of river discharge regime in Latvia

2008 ◽  
Vol 39 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Maris Klavins ◽  
Valery Rodinov
Keyword(s):  
Climate Variability ◽  
River Discharge ◽  
Water Resource Management ◽  
Regional Climate ◽  
Hydrological Regime ◽  
High Water ◽  
Regime Changes ◽  
Long Term Changes ◽  
Discharge Regime

The study of changes in river discharge is important for regional climate variability characterization and for development of an efficient water resource management system. The hydrological regime of rivers and their long-term changes in Latvia were investigated. Four major types of river hydrological regimes, which depend on climatic and physicogeographic factors, were characterized. These factors are linked to the changes observed in river discharge. Periodic oscillations of discharge, and low- and high-water flow years are common for the major rivers in Latvia. A main frequency of river discharge regime changes of about 20 and 13 years was estimated for the studied rivers. A significant impact of climate variability on the river discharge regime has been found.

scholarly journals Optimization of Year-End Water Level of Multi-Year Regulating Reservoir in Cascade Hydropower System Considering the Inflow Frequency Difference

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5345
Author(s):  
Zhiqiang Jiang ◽  
Peibing Song ◽  
Xiang Liao
Keyword(s):  
Power Generation ◽  
Dynamic Programming ◽  
Water Level ◽  
Water Levels ◽  
Least Square ◽  
Frequency Difference ◽  
Impact Factors ◽  
Cascade System ◽  
Cascade Reservoirs ◽  
Hydropower System

In order to analyze the year-end water level of multi-year regulating reservoir of the cascade hydropower system, this paper studied the joint operation optimization model of cascade reservoirs and its solving method based on multi-dimensional dynamic programming, and analyzed the power generation impact factors of cascade system that contains multi-year regulating reservoir. In particular, taking the seven reservoirs in the middle and lower reaches of Yalong River as an example, the optimal year-end water levels of multi-year regulating reservoir under the multi-year average situation and different inflow frequencies situation were studied. Based on the optimal calculation results of multi-dimensional dynamic programming, the inflow frequency difference considered operation rule of year-end water level of Lianghekou reservoir was extracted using the least square principle. The simulation results showed that, compared with the fixed year-end water level in multi-year, the extracted rule can improve the cascade power generation by more than 400 million kWh in an average year, representing an increase of 0.4%. This result means that the extracted rule can give full play to the regulation performance of multi-year regulating reservoir and improve the conversion efficiency of hydropower resources in cascade system. This is of great significance to the practical operation of cascade reservoirs system that contains multi-year regulating reservoir.

scholarly journals Proglacial river dataset from the Akuliarusiarsuup Kuua River northern tributary, Southwest Greenland, 2008–2010

2011 ◽  
Vol 4 (1) ◽  
pp. 71-97 ◽  
Author(s):  
A. K. Rennermalm ◽  
L. C. Smith ◽  
V. W. Chu ◽  
R. R. Forster ◽  
J. E. Box ◽  
...  
Keyword(s):  
Water Level ◽  
Statistical Tests ◽  
Ice Sheet ◽  
High Water ◽  
Stream Channels ◽  
Discharge Data ◽  
Lake Water Level ◽  
Considerable Uncertainty ◽  
Added Uncertainty ◽  
Southwest Greenland

Abstract. Pressing scientific questions concerning the Greenland ice sheet's climatic sensitivity, hydrology, and contributions to current and future sea level rise require hydrological datasets to resolve. While direct observations of ice sheet meltwater losses can be obtained in terrestrial rivers draining the ice sheet and from lake levels, few such datasets exist. We present a new dataset of meltwater river discharge for the vicinity of Kangerlussuaq, Southwest Greenland. The dataset contains measurements of river water level and discharge for three sites along the Akuliarusiarsuup Kuua (Watson) River's northern tributary, with 30 min temporal resolution between June 2008 and August 2010. Additional data of water temperature, air pressure, and lake water level and temperature are also provided. Discharge data were measured at sites with near-ideal properties for such data collection. Regardless, high water bedload and turbulent flow introduce considerable uncertainty. These were constrained and quantified using statistical techniques, which revealed that the greatest discharge data uncertainties are associated with streambed elevation change and measurements. Large portions of stream channels deepened according to statistical tests, but poor precision of streambed depth measurements also added uncertainty. Data will periodically be extended, and are available in Open Access at doi:10.1594/PANGAEA.762818.

scholarly journals Assessment of the Water Quality of Jatiluhur Reservoir, the Downstream of Citarum Cascade River, Using Selected Physico-Chemical Parameters

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Lieza Corsita ◽  
Arwin Arwin ◽  
Barti Setiani Muntalif ◽  
Indah Rachmatiah Salami
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Water Level ◽  
Hydrological Regime ◽  
Quality Parameters ◽  
Biological Data ◽  
Chemical Parameters ◽  
Stream Flows ◽  
Physico Chemical

Physico-chemistry and biological data were investigated  from  October 2010 until April 2011 of Jatiluhur reservoir. A total of six sampling stations were selected for this study. The discharge and hidrological data were obtained from Perum Jasa Tirta II Jatiluhur. The results showed that the hydrological regime in the reservoir Jatiluhur was affected by global phenomenon La Nina events in 2010 and early in 2011. Stream flows were determined during sampling to range from 78  to 482.5 m3/s. The water quality findings were as follows: pH (6.93-8.81), temperature (26.37-30.6°C), dissolved oxygen (0.733-5.2 mg/l), conductivity (2.45-233µmhos/cm), COD (7.36-96.9 mg/l), turbidity (4.063-65.6 NTU), total phosphate (0.002-0.324 mg/l), total nitrogen (0.99-5.96 mg/l), chlorophyl (2.237-43.37 mg/m3), visibility (30-160 cm). The eutrophication was pronounced at Jatiluhur reservoir. Canonical Correspendence Analysis found that some water quality parameters correlated positively with the discharge and the water level.

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