Journal articles: 'River level fluctuation'

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Muhadi, N. A., A. F. Abdullah, S. K. Bejo, M. R. Mahadi, and A. Mijic. "WATER LEVEL FLUCTUATION USING SURVEILLANCE CAMERA." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVI-4/W3-2021 (January 11, 2022): 257–60. http://dx.doi.org/10.5194/isprs-archives-xlvi-4-w3-2021-257-2022.

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Abstract. Floods are the most frequent type of natural disaster that cause loss of life and damages to personal property and eventually affect the economic state of the country. Researchers around the world have been made significant efforts in dealing with the flood issue. Computer vision is one of the common approaches being employed which include the use of image segmentation techniques for image understanding and image analysis. The technique has been used in various fields including in flood disaster applications. This paper explores the use of a hybrid segmentation technique in detecting water regions from surveillance images and introduces a flood index calculation to study water level fluctuations. The flood index was evaluated by comparing the result with water level measured by sensor on-site. The experimental results demonstrated that the flood index reflects the trend of water levels of the river. Thus, the proposed technique can be used in detecting water regions and monitoring the water level fluctuation of the river.

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Bhandari, Sushmita, Kabita Karki, Surendra Maharjan, and Suresh Das Shrestha. "Groundwater flow pattern and water level fluctuation in western parts of Chitwan valley." Journal of Nepal Geological Society 50, no. 1 (December 21, 2016): 51–54. http://dx.doi.org/10.3126/jngs.v50i1.22863.

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Study of flow pattern and water level fluctuation in the western part of the Chitwan Valley was carried out in the area of 274.48 km2. The study area consists of alluvial deposits of the Narayani and the Rapti River of Pleistocene to Recent age. Aquifers in the study area are unconfined and semi confined to confined types. Based on the static water level, Jagatpur, Sukranagar and Gunjanagar are deep tube well zone and Shivanagar, Parbatipur, Patihani, Gitanagar are shallow tube well zone. The western half area discharges groundwater to the Narayani River and southern half discharges to the Rapti River rather than getting recharged throughout the year. Average water level fluctuation is 2.34 m with high fluctuation of 4.88 m at Sukranagar and low 0.49 m at Dibyanagar VDC. This fluctuation is directly related to rainfall.

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Zhang, Zong Pu, Fu Lin Cai, Yu Long Hua, and Huan Cheng. "Study on the Influence of Tailrace Tunnel Outlet Bottom Slope on Water Level Fluctuation in the Tailrace Surge Tank." Advanced Materials Research 1065-1069 (December 2014): 644–49. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.644.

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Combining with hydraulic model experiment of water diversion and power generation system of one hydropower station, the effects of different connection patterns between the tailrace tunnel outlet and downstream river bed and flow states in the transient process on the water level fluctuation in tailrace surge tank have been investigated. The results show that: there is not remarkable influence on water level fluctuation when tailrace water level in downstream river is higher or close to the ceiling height. On the opposite side , it has notable influence on water level fluctuation in the tailrace surge tank when tailrace water level in downstream is lower than the ceiling height, and the water level fluctuation in tailrace surge tank presents some regularity under the same connection pattern when the tailrace water level in downstream river is lower than the ceiling height.

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Ji, Qianfeng, Shudan Xue, Quan Yuan, Yuan Yuan, Yuanming Wang, Ruifeng Liang, Jingjie Feng, Kefeng Li, and Ran Li. "The Tolerance Characteristics of Resident Fish in the Upper Yangtze River under Varying Gas Supersaturation." International Journal of Environmental Research and Public Health 16, no. 11 (June 6, 2019): 2021. http://dx.doi.org/10.3390/ijerph16112021.

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In circumstances where total dissolved gas (TDG) levels are variable, the peak TDG and duration are expected to be the dominant drivers of fish survival. Focusing on the peak TDG and duration in natural rivers, a laboratory experiment and field experiments in the upper Yangtze River were conducted with Prenant’s Schizothoracin (Schizothorax prenanti), a rare species inhabiting the upper Yangtze River, to examine the tolerance characteristics of fish under varying gas supersaturation levels. The results of the field experiments showed that TDG supersaturation in natural rivers changed greatly during the flood period due to reservoir regulation. The survival of fish was affected by TDG levels, water depth and TDG fluctuation range. A high TDG level, and shallow compensatory water depth caused fish mortality in the field experiment to be higher in September than in July. The results of the laboratory experiment showed that fish tolerance was lower under fluctuating TDG supersaturation than under constant TDG supersaturation. The tolerance of fish to TDG supersaturation varied depending on peak TDG and duration. Under the fluctuation range of 115–125%, fish survival in the 6 h–6 h cycle was significantly different from that in the 8 h–8 h cycle. The fluctuation cycle did not affect fish survival at the fluctuation range of 110–130%. Intermittent lower TDG supersaturation does not significantly increase the tolerance of fish. This study revealed the tolerance characteristics of resident fish in the upper Yangtze River to TDG supersaturation, which provides a reference to the ecological operation of reservoirs and may contribute to the protection of aquatic organisms.

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Que, Yanfu, Jiayi Xie, Jun Xu, Weitao Li, Ezhou Wang, and Bin Zhu. "Ecological Influences of Water-Level Fluctuation on Food Web Network." Water 13, no. 17 (August 29, 2021): 2371. http://dx.doi.org/10.3390/w13172371.

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Seasonal water-level fluctuations may lead to changes in river nutrients, which causes corresponding changes in the trophic structure of an aquatic food web, and finally affects the whole ecosystem. In this study, we focused on the Ganjing River, a tributary of the Yangtze River, China. Common organisms were sampled and measured for carbon and nitrogen stable isotopes in the wet and dry seasons, respectively, and the relative contributions of different food sources were combined to construct the food web, so as to realize the influence of water-level fluctuation on aquatic food web. Our results showed that basal food sources for fish consumers were endogenous carbon sources such as POM, zooplankton and zoobenthos in the dry season, while high water level exposed fish to more diverse and abundant food sources, and the contribution proportions of exogenous carbon sources (e.g., terrestrial detritus) to consumers increased in the wet season. In parallel, the abundance and species diversity of fish were higher than those in the dry season. Most fish species had relatively higher trophic levels in the dry season compared to the wet season, because the increase in fish densities led to an increase in piscivores fish. The food web was composed of planktonic and benthic food chains in the dry season. During the wet season, the planktonic food chain was dominant, followed by the herbivorous food chain, and the benthic food chain was relatively less important. Therefore, water-level fluctuation may alter the trophic linkages within fish communities, which contributed to a more complex and interconnected food web. Moreover, as we expect, the stable isotope analysis food web was broadly in line with the gut content analysis food web.

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Shafeek, Ahmed M., Hamdy Salah, Nabila Shehata, and A. B. Saddek. "The impact of fluctuation of the Nile River level on water composition." Water Practice and Technology 12, no. 2 (June 1, 2017): 423–31. http://dx.doi.org/10.2166/wpt.2017.040.

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This paper studies the influence of fluctuation of the Nile River level on water composition. The Nile River could be classified to four periods according to level. The periods are flood, intermediate, drought and intermediate. The present study investigates the biological and chemical analysis of water at all periods of the Nile River. The results show that the algae count ranged from 221 to 2,069 organism/ml during flood and drought periods respectively. By contrast, the change in the concentration of chemical elements was very slight, whether in the period of drought or flood period. This means that the fluctuation of the Nile River level had a significant impact on its biological nature rather than chemical nature. It could be argued that this is due to the algae's ability to absorb chemical elements.

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Matsumura-Tundisi, T., JG Tundisi, F. Souza-Soares, and JEM Tundisi. "Zooplankton community structure of the lower Xingu River (PA) related to the hydrological cycle." Brazilian Journal of Biology 75, no. 3 suppl 1 (August 2015): 47–54. http://dx.doi.org/10.1590/1519-6984.03814bm.

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Abstract The zooplankton community of the lower Xingu River shows strong fluctuations in species richness and number of organisms during periods of water level fluctuation. Pulses of density and species richness are adapted to the pulses in water flows and water level. This is conected with reproductive strategies of some zooplankton groups. The spatial heterogeneity of the lower Xingu River consisting of braided channels, bedrocks, macrophyte stands, is probably a relevant factor for the species richness of the zooplankton communities, and may be a fundamental factor for the overall aquatic biodiversity of the lower Xingu River.

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Dahlstedt, Kajsa, and Henrik Jeldtoft Jensen. "Fluctuation spectrum and size scaling of river flow and level." Physica A: Statistical Mechanics and its Applications 348 (March 2005): 596–610. http://dx.doi.org/10.1016/j.physa.2004.09.039.

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Yu, Hui, Qiang Li, Li Xin Wei, Zhong Kai Xiao, Shuang Cao, and Wei Guo Zhang. "The Pattern and Cause Analysis of Tidal Level Fluctuation of the Yangtze River in Nanjing Section." Applied Mechanics and Materials 641-642 (September 2014): 101–7. http://dx.doi.org/10.4028/www.scientific.net/amm.641-642.101.

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This paper used the Mann-Kendall test, Spearman rank correlation test, Pettitt-Mann-Whitney change-point statistics, and complex Morlet wavelet analysis method to analyze the trend, change-point, and period of the tidal level at Nanjing Station from 1950 to 2012. The results demonstrated that there was a significant increase of annual highest and lowest tidal levels, while the trend of annual average tidal level change was not obvious. Significant mutations existed not only in the term of annual highest tidal level but also in the lowest one: the annual highest tidal level increased by 0.49m after 1972, while the annual lowest one increased by 0.29m after 1982. The period of annual average tidal level, highest one, and lowest one were 10 years, 15 years, and 14 years respectively. The scale of fluctuations in the annual highest tidal level was close to the annual lowest tidal level. The cause analysis of fluctuation indicated that runoff variation was the dominant factor of tidal level change.

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Kong, Bo, Huan Yu, and He Ping Tao. "Responses Analysis on Groundwater Level Fluctuations in Coastal Wetland." Advanced Materials Research 518-523 (May 2012): 4222–26. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.4222.

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We analyzed the relationship of groundwater level of wetlands at the Yellow River mouth to the ocean tide responses, as well as its impact on the spatial distribution of wetland types by field positioning observations of coastal wetland groundwater levels. The results showed that, the groundwater level is significantly affected by the tides. Its fluctuation has a negative polynomial relationship with its distance to the coast. Their correlation reached maximum during spring tide (R2=0.79); the closer to the coast, the greater the groundwater level fluctuation is, the greater the interaction between the seawater and the groundwater, the smaller the groundwater depth; In contrast, the further from the coast, the smaller the level fluctuation is, the greater the groundwater depth level. The spatial distribution of coastal wetlands is greatly affected by groundwater level and ocean tide. Thus reasonable protection of the region is of importance for protection of both the seawater and groundwater qualities.

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Xin, Yawen, Zhifang Zhou, Mingwei Li, and Chao Zhuang. "Analytical Solutions for Unsteady Groundwater Flow in an Unconfined Aquifer under Complex Boundary Conditions." Water 12, no. 1 (December 24, 2019): 75. http://dx.doi.org/10.3390/w12010075.

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The response laws of groundwater dynamics on the riverbank to river level variations are highly dependent on the river level fluctuation process. Analytical solutions are widely used to infer the groundwater flow behavior. In analytical calculations, the river level variation is usually generalized as instantaneous uplift or stepped, and then the analytical solution of the unsteady groundwater flow in the aquifer is derived. However, the river level generally presents a complex, non-linear, continuous change, which is different from the commonly used assumptions in groundwater theoretical calculations. In this article, we propose a piecewise-linear approximation to describe the river level fluctuation. Based on the conceptual model of the riverbank aquifer system, an analytical solution of unsteady groundwater flow in an unconfined aquifer under complex boundary conditions is derived. Taking the Xiluodu Hydropower Station as an example, firstly, the monitoring data of the river level during the period of non-impoundment in the study area are used to predict the groundwater dynamics with piecewise-linear and piecewise-constant step approximations, respectively, and the long-term observation data are used to verify the calculation accuracy for the different mathematical models mentioned above. During the reservoir impoundment period, the piecewise-linear approximation is applied to represent the reservoir water level variation, and to predict the groundwater dynamics of the reservoir bank.

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Yaitskaya, Natalia A., and Igor V. Sheverdyaev. "Digital Elevation Model Development Of The Volga And Don River’s Delta And Application In Hydrological Modeling." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 15, no. 4 (January 18, 2023): 181–87. http://dx.doi.org/10.24057/2071-9388-2022-035.

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The article describes the methodology for constructing digital elevation models for the vast delta areas of the Don and Volga rivers for further use in mathematical models of flooding from surges. The initial cartographic data and features of the delta regions are described. The methods of information processing are considered in detail. An algorithm for constructing a DEM has been developed to obtain highly detailed digital elevation models. The algorithm is based on combining the DEM of individual key features - land, the depths of the hydrographic network and the bathymetry of the receiving reservoir for the river. The topographic maps, maps of the navigable route depths, hydrographic maps, and satellite images Landsat-8 and Sentinel-2 were used to create the DEM of the Don and Volga river. To build individual DEMs, a raster of the absolute depth of the channels, a hydrography DEM, a land DEM, and a shelf DEM were created using geoinformation systems. To assess the possibility of using obtained DEMs in hydrological models based on HEC-RAS, we conducted training and verification calculations of water level during wind surge phenomena in Don Delta using different surface roughness coefficients. The calculation results show good reproducibility of observed water level fluctuation in the Don Delta using obtained DEM with a roughness coefficient of 0.0125. Also, we carried out similar calculations of storm surge phenomena in the Volga Delta using obtained DEM and combinations of various riverbed and not riverbed roughness coefficients. The combination of 0.007 for riverbed and 0.02 for not riverbed surfaces reproduces the observed water level fluctuation during storm surge phenomena in Volga Delta. The constructed DEMs for the Volga and Don deltas made it possible to reproduce the observed dynamics of river discharges and water level fluctuations during surge events. Such detailed DEMs, taking into account all the complexity of the coastal and delta relief, were created for the first time for the Volga and Don.

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Ning, Lixin, Yunkai Zhou, Jing Yang, Changxiu Cheng, Changqing Song, and Shi Shen. "Spatial-temporal variability of the fluctuation of water level in Poyang Lake basin, China." Open Geosciences 10, no. 1 (December 31, 2018): 940–53. http://dx.doi.org/10.1515/geo-2018-0075.

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Abstract Poyang Lake basin is one of the most biodiversity areas in China. Fluctuation of water level is an important factor of hydrological process which is a guarantee of ecosystem health and biodiversity conservation. To measure its spatial-temporal variation, classical statistical methods and permutation entropy were employed: 1) Variation of water level downstream of Poyang Lake during one year follows a periodical pattern, while it is random in upper reaches. That is, the range of water level in upper reaches is much less than that in downstream. 2) Fluctuation of water level in winter and spring is more complicated, more irregular and more random than that in other seasons. This is because in winter and spring, precipitation directly causes rising in water level rather than generating surface runoff, while it is reversed in summer. 3) The ranges, standard deviation, coefficient of variation and fluctuation of water level decrease with rising in elevation. 4) In sub-basin scale, fluctuation of water level in upper reaches is more complicated than that in downstream, e specially along one river. Mechanically, catchment size and confluence process may be the main factors influencing fluctuation of water level over Poyang Lake basin.

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Santos, Anderson Medeiros dos, and Sidinei Magela Thomaz. "Short term fluctuations and succession trends in tropical floodplain vegetation measured by correspondence analysis." Brazilian Archives of Biology and Technology 51, no. 4 (August 2008): 581–91. http://dx.doi.org/10.1590/s1516-89132008000400016.

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The aim of this work was to study the aquatic macrophytes community development to distinguish the fluctuations from succession trends at different temporal and spatial scales in the Upper Paraná River floodplain. The samples were collected quarterly from May 2000 to March 2002 in seven lakes with different degrees of connectivity from the main river channel and analyzed by between-class correspondence analysis. It was difficult to establish any pattern of community development at local scale but at a higher level of organization, disconnected lakes were characterized by fluctuation of the floristic composition. Connected lakes showed a straight trajectory, indicating that succession was occurring at these sites. Probably the income of propagules and diaspores from the river into connected lakes was the driving force of the observed change in community composition.

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DOĞAN, Uğur, Serdar YEŞİLYURT, Gönül MUTLU, and Ali KOÇYİĞİT. "Base-level poljes in the Sivas gypsum karst, Türkiye." Jeomorfolojik Araştırmalar Dergisi, no. 9 (November 15, 2022): 19–37. http://dx.doi.org/10.46453/jader.1125343.

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The Sivas Basin, Central Anatolia, includes one of the most outstanding gypsum karst terrains in the world, covering an area of 2140 km2. The karst landscapes are developed on late Eocene gypsum deposits. The fact that the polje shapes that are commonly seen in the limestone karst terrain also seen in the Sivas gypsum karst area further increases the importance of this area in terms of geomorphology. This study is focused on the explanation of the morphometric properties and formation mechanism of poljes around the Kızılırmak River in the Sivas gypsum karst area. The geomorphological evolution of the Sivas gypsum karst area was controlled by the Kızılırmak River drainage system formed in the Early Pliocene. Polygonal doline karst is common on the High Karst Plateau (or erosional-denudational surface) formed during this evolution process, while subsidence dolines, hanging valleys, and poljes are common on the Low Karst Plateau. A total of 14 poljes, most of which are drained underground, and a corrosion plain were identified around the Kızılırmak River in the Low Karst Plateau. The boundaries of some of the poljes, the area of the largest of which is 6.3 km2, and hence their strike is controlled by faults. These poljes are base-level poljes, which bases are approximately at the river level and developed in the water table fluctuation zone. In addition to the structural lines in the formation of the poljes, the beginning of a blind valley-like karstification process, especially in the lower parts of the hanging valleys, mostly as a result of the collapse doline formation (showing the estevalle feature), changes in the water table level in the epiphreatic zone, and in addition to the precipitation, the aggressive river floodwaters that invaded the polje floor were effective. Due to the rapid dissolution of gypsum, the development of polje must have been affected by the incision and deposition periods of the river. The Tödürge Lake depression most probably has been shaped by collapse dolines.

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Musarat, Muhammad Ali, Wesam Salah Alaloul, Muhammad Babar Ali Rabbani, Mujahid Ali, Muhammad Altaf, Roman Fediuk, Nikolai Vatin, et al. "Kabul River Flow Prediction Using Automated ARIMA Forecasting: A Machine Learning Approach." Sustainability 13, no. 19 (September 27, 2021): 10720. http://dx.doi.org/10.3390/su131910720.

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The water level in a river defines the nature of flow and is fundamental to flood analysis. Extreme fluctuation in water levels in rivers, such as floods and droughts, are catastrophic in every manner; therefore, forecasting at an early stage would prevent possible disasters and relief efforts could be set up on time. This study aims to digitally model the water level in the Kabul River to prevent and alleviate the effects of any change in water level in this river downstream. This study used a machine learning tool known as the automatic autoregressive integrated moving average for statistical methodological analysis for forecasting the river flow. Based on the hydrological data collected from the water level of Kabul River in Swat, the water levels from 2011–2030 were forecasted, which were based on the lowest value of Akaike Information Criterion as 9.216. It was concluded that the water flow started to increase from the year 2011 till it reached its peak value in the year 2019–2020, and then the water level will maintain its maximum level to 250 cumecs and minimum level to 10 cumecs till 2030. The need for this research is justified as it could prove helpful in establishing guidelines for hydrological designers, the planning and management of water, hydropower engineering projects, as an indicator for weather prediction, and for the people who are greatly dependent on the Kabul River for their survival.

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Zhao, Tongzhou, Liang Wu, Dehua Li, and Yiming Ding. "Multifractal Analysis of Hydrologic Data Using Wavelet Methods and Fluctuation Analysis." Discrete Dynamics in Nature and Society 2017 (2017): 1–18. http://dx.doi.org/10.1155/2017/3148257.

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We study the multifractal properties of water level with a high-frequency and massive time series using wavelet methods (estimation of Hurst exponents, multiscale diagram, and wavelet leaders for multifractal analysis (WLMF)) and multifractal detrended fluctuation analysis (MF-DFA). The dataset contains more than two million records from 10 observation sites at a northern China river. The multiscale behaviour is observed in this time series, which indicates the multifractality. This multifractality is detected via multiscale diagram. Then we focus on the multifractal analysis using MF-DFA and WLMF. The two methods give the same conclusion that at most sites the records satisfy the generalized binomial multifractal model, which is robust for different times (morning, afternoon, and evening). The variation in the detailed characteristic parameters of the multifractal model indicates that both human activities and tributaries influence the multifractality. Our work is useful for building simulation models of the water level of local rivers with many observation sites.

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Duong Thi, Toan, and Duc Do Minh. "Riverbank Stability Assessment under River Water Level Changes and Hydraulic Erosion." Water 11, no. 12 (December 10, 2019): 2598. http://dx.doi.org/10.3390/w11122598.

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The dominant mechanism of riverbank cantilever failure is soil erosion of the bank toe and near bank zone. This paper demonstrates that the shape of the riverbank cantilever failure depends on the properties of the soil and the fluctuation of the river water level (RWL). With a stable RWL, a riverbank with higher resistance force leads to failure with larger and deeper overhang erosion width. When RWL rises, a less cohesive soil bank will be eroded over a larger width and riverbank failure will occur earlier. With a low rate of rising RWL, riverbank failure may happen in a type of mass failure. With a high rate of rising RWL, a riverbank will fail in a type of overhang riverbank failure, with the soil erosion rate being the main affected factor.

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TANAKA, Hitoshi, and Hyun-seok LEE. "STUDY ON WATER LEVEL FLUCTUATION DUE TO WAVE SET-UP IN A RIVER MOUTH." Doboku Gakkai Ronbunshuu B 62, no. 2 (2006): 210–23. http://dx.doi.org/10.2208/jscejb.62.210.

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TSUCHIYA, Mitsukuni, and Kiyoshi IZUMI. "Relationship between Fluctuation of Unconfined Groundwater Level and Base Flow in Urban River Basing." PROCEEDINGS OF HYDRAULIC ENGINEERING 36 (1992): 641–46. http://dx.doi.org/10.2208/prohe.36.641.

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Awang Shariee, A. M. S., I. N. Mohamad, and W. K. Lee. "Backwater Effect of Tidal Water Level Fluctuation and Riverine Discharge in An Idealized River." IOP Conference Series: Earth and Environmental Science 498 (June 16, 2020): 012055. http://dx.doi.org/10.1088/1755-1315/498/1/012055.

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Li, Xiang, Chenyang Zhao, Raoul Hölter, Maria Datcheva, and Arash Alimardani Lavasan. "Modelling of a Large Landslide Problem under Water Level Fluctuation—Model Calibration and Verification." Geosciences 9, no. 2 (February 14, 2019): 89. http://dx.doi.org/10.3390/geosciences9020089.

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In past centuries, reservoir landslides have been always a threat that brought a big loss in lives and properties. The phenomena that have decisive influence on the landslide instability are quite complex and the importance of each of them for the stability of a particular landslide differs. Therefore, it is extremely important to distinguish between the effects that different phenomena have and to identify those that dominate the behaviour of the studied landslide. The aim of the present study is to investigate the behaviour under the river level fluctuation of a large landslide in China, namely the Huangtupo landslide. A 2D numerical model of a selected part of the Huangtupo landslide is created and a series of fully coupled hydro-mechanical simulations have been conducted to investigate the landslide behaviour under different influencing factors (e.g., mechanical incidents, water head, soil water permeability, etc.). Furthermore, both local and global sensitivity analyses are performed to assess the importance of these influencing factors and to select the most influential model parameters. Thereafter, back analysis is employed to calibrate the model against real field data. Finally, the capability of the calibrated model is evaluated and the results show that it can simulate appropriately the long-term behaviour of the landslide after the river level reaches its maximal level.

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Jin, Juxiang, Scott A. Wells, Defu Liu, Guolu Yang, Senlin Zhu, Jun Ma, and Zhengjian Yang. "Effects of water level fluctuation on thermal stratification in a typical tributary bay of Three Gorges Reservoir, China." PeerJ 7 (May 15, 2019): e6925. http://dx.doi.org/10.7717/peerj.6925.

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Xiangxi River is a typical tributary of Three Gorges Reservoir (TGR) in China. Based on field observations in 2010, thermal stratification was significant in most months of the year. Through field data analysis and numerical simulations, the seasonal and spatial variation of thermal stratification as related to the impact of the operation of TGR were investigated. Thermal stratification was most pronounced from April to September in the Xiangxi River tributary. Air temperature (AT) and water level (WL) were the two dominant variables impacting thermal stratification. AT affected the surface water temperature promoting the formation of thermal stratification, and high WLs in TGR deepened the thermocline depth and thermocline bottom depth. These results provide a preliminary description of the seasonal variation and spatial distribution of thermal stratification, which is important for better understanding how thermal stratification affects algae blooms in Xiangxi River.

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SAWAMURA, Naoki, and Kenichi MAEDA. "INFLUENCE OF WATER LEVEL FLUCTUATION AND FOUNDATION GROUND STRUCTURE ON PIPING OF RIVER LEVEE FOCUS ON WATER LEAKAGE." Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 78, no. 2 (2022): I_661—I_666. http://dx.doi.org/10.2208/jscejhe.78.2_i_661.

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Yang, Na, Yehui Zhang, and Kai Duan. "Effect of Hydrologic Alteration on the Community Succession of Macrophytes at Xiangyang Site, Hanjiang River, China." Scientifica 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/4083696.

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With the intensification of human activities over the past three decades in China, adverse effects on river ecosystem become more serious especially in the Hanjiang River. Xiangyang site is an important spawn ground for four domestic fishes in the downstream region of Hanjiang River. Based on the field survey results of macrophytes during 1997–2000 and 2013-2014, community succession of aquatic macrophytes at Xiangyang site was evaluated and discussed. Two-key ecologic-related hydrologic characteristics, flow regime and water level, were identified as the main influence factors. The EFC (environmental flow components) parameters were adopted to evaluate the alteration of flow regimes at Xiangyang site during 1941–2013. Evaluation results demonstrate a highly altered flow process after being regulated by reservoir. The flow patterns tend to be an attenuation process with no large floods occurring but a higher monthly low flow. Furthermore, the water level decreased and fluctuation reduced after the dam was built, which caused the decrease of biomass but favored the submerged macrophytes during 1995–2009. However, with the water level increasing after 2010 and gently fluctuating, due to uplift by the hydraulic projects downstream as well as the flow attenuation, the dominant position of submerged macrophytes will be weakened.

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Dai, Xue, Rongrong Wan, and Guishan Yang. "Non-stationary water-level fluctuation in China’s Poyang Lake and its interactions with Yangtze River." Journal of Geographical Sciences 25, no. 3 (January 11, 2015): 274–88. http://dx.doi.org/10.1007/s11442-015-1167-x.

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Jin, Qiu, Huazu Liu, Xiaoguang Xu, Li Zhao, Liangang Chen, Liming Chen, Ruijie Shi, and Wei Li. "Emission dynamics of greenhouse gases regulated by fluctuation of water level in river-connected wetland." Journal of Environmental Management 329 (March 2023): 117091. http://dx.doi.org/10.1016/j.jenvman.2022.117091.

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Otsuka, K., N. Ogawa, S. Iio, T. Kitahora, Y. D. Choi, and M. Inagaki. "Characteristics and suppression of vibration in cross-flow turbine with a cavity." Journal of Physics: Conference Series 2217, no. 1 (April 1, 2022): 012063. http://dx.doi.org/10.1088/1742-6596/2217/1/012063.

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Abstract Cross-flow turbine is widely used for small hydropower in run-of-river type stations because of its excellent partial load characteristics, easy manufacturing, and low cost. The Banki-Michell turbine is the origin, and various studies have focused on improving the turbine performance. The authors have developed a new cross-flow turbine with a cavity and a guide wall from the outer nozzle wall tip to suppress flow separation on the guide wall and make the casing smaller. However, little researches are focusing on vibration, and it is also essential to get knowledge for suppressing vibration and noise from the turbine aiming to install at higher head sites. Our previous studies showed that high-pressure fluctuation occurs near the outer nozzle tip, and the cavity suppresses the pressure fluctuations, but the suppression mechanism is not fully understood. Therefore, this study experimentally investigates the pressure fluctuation generation mechanism and the cavity’s effect on suppressing the vibration. Furthermore, it aims to suppress the vibration by modifying the nozzle tip shape. The vibration level was measured on a lab-scale turbine and CFD analysis to reveal the generation of pressure fluctuation. As a result, the predominant frequency of the vibration corresponds to the blade passing frequency and the pressure fluctuation at the nozzle tip. The cavity and nozzle tip shape show a significant influence on pressure and vibration characteristics and turbine performance.

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Afzaal, Hassan, Aitazaz A. Farooque, Farhat Abbas, Bishnu Acharya, and Travis Esau. "Groundwater Estimation from Major Physical Hydrology Components Using Artificial Neural Networks and Deep Learning." Water 12, no. 1 (December 18, 2019): 5. http://dx.doi.org/10.3390/w12010005.

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Precise estimation of physical hydrology components including groundwater levels (GWLs) is a challenging task, especially in relatively non-contiguous watersheds. This study estimates GWLs with deep learning and artificial neural networks (ANNs), namely a multilayer perceptron (MLP), long short term memory (LSTM), and a convolutional neural network (CNN) with four different input variable combinations for two watersheds (Baltic River and Long Creek) in Prince Edward Island, Canada. Variables including stream level, stream flow, precipitation, relative humidity, mean temperature, evapotranspiration, heat degree days, dew point temperature, and evapotranspiration for the 2011–2017 period were used as input variables. Using a hit and trial approach and various hyperparameters, all ANNs were trained from scratched (2011–2015) and validated (2016–2017). The stream level was the major contributor to GWL fluctuation for the Baltic River and Long Creek watersheds (R2 = 50.8 and 49.1%, respectively). The MLP performed better in validation for Baltic River and Long Creek watersheds (RMSE = 0.471 and 1.15, respectively). Increased number of variables from 1 to 4 improved the RMSE for the Baltic River watershed by 11% and for the Long Creek watershed by 1.6%. The deep learning techniques introduced in this study to estimate GWL fluctuations are convenient and accurate as compared to collection of periodic dips based on the groundwater monitoring wells for groundwater inventory control and management.

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Ivkina, N. I., and A. V. Galayeva. "ASSESSMENT OF FLUCTUATIONS IN THE CASPIAN SEA LEVEL UNDER THE INFLUENCE OF CLIMATE CHANGE FOR THE FUTURE UNTIL 2050." Hydrometeorology and ecology 100, no. 1 (2021): 70–77. http://dx.doi.org/10.54668/2789-6323-2021-100-1-70-77.

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The article considers the possible fluctuation of the Caspian Sea level in the future until 2050, taking into an account the climate changes. For this purpose, possible changes in the river inflow to the sea and meteorological parameters (precipitation, air temperature and evaporation from the water surface) were predicted. Changes in the meteorological parameters were estimated according to two climate scenarios RCP4. 5 and RCP8.5.

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LI, CHUNLIN, YANG YANG, ZHEN WANG, LING YANG, DONGMEI ZHANG, and LIZHI ZHOU. "The relationship between seasonal water level fluctuation and habitat availability for wintering waterbirds at Shengjin Lake, China." Bird Conservation International 29, no. 1 (April 2, 2018): 100–114. http://dx.doi.org/10.1017/s0959270918000035.

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SummaryConservation plans for waterbirds in periodically flooded wetlands should be based on a deep understanding of the relationship between habitat availability and the hydrological regime. Using waterbird surveys and remotely sensed images, we investigated how habitat availability for wintering waterbirds was regulated by seasonal water level fluctuation at Shengjin Lake in the lower Yangtze River floodplain, which is an important wintering area along the East Asian-Australasian Flyway. We recorded 52 waterbird species during three field surveys, and categorised them into four groups based on their foraging preferences: grassland, mudflats, shallow water, or deep water. Habitat availability for the four groups was significantly influenced by fluctuations in water level. Habitat for deep-water feeders dominated the lake throughout the year, despite contracting during the wintering season. Water recession during winter exposed more diverse riparian habitats that showed high spatial heterogeneity at the landscape level, with the Upper Lake providing the most suitable habitats for the most diverse and abundant waterbirds. It is worth noting that the water level was regulated highly for aquaculture during the early wintering period, impeding access to suitable habitats for the early-arriving waterbirds that foraged in the riparian mudflats and grassland. Furthermore, rapid water recession from the opening of a sluice gate allowed the exposed moist mudflats to dry up quickly, reducing its suitability for shorebirds and cranes. For effective wintering waterbird conservation in the ephemeral lacustrine wetlands in the Yangtze River floodplain, we suggest stepwise water recession plans, together with the recovery of the aquatic vegetation community and reduction in high-density aquaculture, to synchronise the exposure of foraging habitats with the migration phenology of different waterbird species.

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Liu, Yanmin, Hao Wang, Yungang Wu, Yuan Zhao, and Xingwei Ren. "Aquifer Response to Stream-Stage Fluctuations: Field Tests and Analytical Solution for a Case Study of the Yangtze River in Wuhan, China." Water 13, no. 17 (August 30, 2021): 2388. http://dx.doi.org/10.3390/w13172388.

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In this paper, field hydrological monitoring tests and an analytical solution for the aquifer response (i.e., the groundwater head) to stream-stage fluctuations are presented through a case study of the Yangtze River in Wuhan, China. A sinusoidal equation for the stream water level over time is proposed and is verified by the monitoring results. Based on the classical 1-D solution of ground water flow equations, a new flow model was proposed to analyze the confined aquifer response to stream-stage fluctuations. The groundwater head of the confined aquifer can then be calculated by embedding the proposed sinusoidal equation of the stream-stage fluctuation into the new flow model. Field monitoring data of the three hydrological years from 2017 to 2019 were compiled to evaluate the proposed model. The results show that the predicted groundwater head of the confined aquifer matches well with the monitoring data. The prediction error of the proposed model (about 8%) is much lower than that of the previous model (about 26%). This paper presents an improved analytical model with a satisfying capability to predict the response of the groundwater head of the confined aquifer to stream-stage fluctuation. This model can be applied into groundwater flow models (such as MODFLOW, FEFLOW, etc.). The results of this study provide a valuable hydrological resource for underground practical engineering in the riverside area, especially in the first terrace of the Yangtze River, and for the dewatering design of a foundation pit in a riverside area.

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Moon, J. W., Y. Song, H. S. Moon, and G. H. Lee. "Clay minerals from tidal flat sediments at Youngjong Island, Korea, as a potential indicator of sea-level change." Clay Minerals 35, no. 5 (December 2000): 841–55. http://dx.doi.org/10.1180/000985500547278.

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AbstractClay minerals from the tidal flat sediments along the coast of Youngjong Island, west of mainland Korea, were studied to ascertain their potential as an indicator of sea-level fluctuation. Semi-quantitative analysis of their clay-size fractions by XRD shows that the vertical distribution of clay minerals can be separated into four clay mineral assemblage units. Based on the relative contents of chlorite, four sedimentary units are distinguishable, and the abundance of chlorite is inversely related to that of smectite. The kaolinite content is constant, and so it is clear that chlorite originating from the Han River was transformed to smectite by pedogenesis during regression periods. Therefore, the relative contents of clay minerals from the unconsolidated materials in the tidal flat of Youngjong Island canbe used as indicators of transgression and regression in accordance with the sea-level fluctuation.

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Cai, Wei, Yi Li, Peifang Wang, Lihua Niu, Wenlong Zhang, and Chao Wang. "Revealing the relationship between microbial community structure in natural biofilms and the pollution level in urban rivers: a case study in the Qinhuai River basin, Yangtze River Delta." Water Science and Technology 74, no. 5 (June 21, 2016): 1163–76. http://dx.doi.org/10.2166/wst.2016.224.

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River pollution is one of the most challenging environmental issues, but the effect of river pollution levels on the biofilm communities has not been well-studied. Spatial and temporal distribution characteristics of environmental parameters and the biofilm communities were investigated in the Qinhuai River basin, Nanjing, China. Water samples were grouped into three clusters reflecting their varying pollution levels of relatively slight pollution, moderated pollution, and high pollution by hierarchical cluster analysis. In different clusters, the biofilm communities mainly differed in the proportion of Actinobacteria, Firmicutes, and Proteobacteria. As the dominant classes of Proteobacteria, Alpha-, Beta- and Gammaproteobacteria seemed to show an upward trend followed by a small fluctuation in the abundance with the escalation of water pollution level. Results of redundancy analysis demonstrated that temperature, total nitrogen to total phosphorus ratios (TN/TP) and concentrations of ammonia nitrogen (NH3-N) and TN were mainly responsible for the variation in bacterial community structure. The occurrences of Alpha-, Beta- and Gammaproteobacteria were closely associated with higher temperature, higher concentrations of NH3-N and TN and a lower TN/TP ratio. This study may provide a theoretical basis for the water pollution control and ecological restoration in urban rivers under different pollution levels.

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Wu, Ray-Shyan, Fiaz Hussain, Yuan-Chien Lin, Tzu-Yu Yeh, and Kai-Chun Yu. "Characterization of Regional Groundwater System Based on Aquifer Response to Recharge–Discharge Phenomenon and Hierarchical Clustering Analysis." Water 13, no. 18 (September 15, 2021): 2535. http://dx.doi.org/10.3390/w13182535.

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The investigations of groundwater hydrograph reasonably reflect the aquifer response to recharge–discharge phenomenon and its characteristics. A better understanding of aquifer characteristics such as regional aquifer classification, recharge and discharge patterns, aquifer geology and flow patterns are the surface indicators that may be more effective and less costly for interpreting basic regional hydrogeological conditions and assessments. This study deals with the application of Hierarchical Clustering Analysis to understand the groundwater spatio-temporal patterns and to visualize/classify the nature of the aquifer in the regional area of Kaohsiung City, Taiwan. Groundwater level fluctuation patterns and slopes of rising and recession limbs are used to identify the pumping effects and classify aquifers. The results of clustering analysis show that the groundwater observation wells in the study area can be divided into five major characteristics along with the upstream to downstream of Kaoping River. The clusters are consistent with basic lithology distribution and age of sedimentary, which represents the characteristics of groundwater level fluctuation. The identified groundwater hydrographs patterns provide newer insights related to aquifer response to recharge–discharge phenomenon, types of aquifers and their behaviors. The knowledge of water level fluctuations in the observation wells provides a piece of prior information about the abstraction of groundwater. The proposed aquifer classification and pumping effect have great potential for applied use in groundwater management e.g., save drilling cost.

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Yan, Shao-feng, Shuang-en Yu, Yu-bai Wu, De-feng Pan, Dong-li She, and Jianzhong Ji. "Seasonal Variations in Groundwater Level and Salinity in Coastal Plain of Eastern China Influenced by Climate." Journal of Chemistry 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/905190.

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The coastline of China is approximately 18,000 km long. In most coastal cities, seawater intrusion is a serious threat to groundwater resources. Nine shallow monitoring wells were constructed to study the dynamics of shallow groundwater level and salinity in the coastal plain region of Jiangsu province, China. Results showed that precipitation, evaporation, and river stage affected the groundwater level in our study area. Positive correlations were observed among the groundwater level, precipitation, and river stage; then negative correlation existed between the groundwater level and evaporation. The influencing factors on the groundwater level were in the order precipitation > river stage > evaporation. Sufficient precipitation during the wet season diluted the groundwater salinity. After the dilution, between two continuous precipitation events, the groundwater salinity increased as the groundwater level decreased. During the dry season, the groundwater salinity rapidly increased and reached its peak in December. The groundwater salinity in December was 23 times higher than that in July. The groundwater level and salinity in this study were generally associated with the season. Climate factors led to fluctuation of groundwater levels and salinity during the wet season, and seawater intrusion increased the groundwater salinity during the dry season.

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Liang, Huidi, and Xudong Zhou. "Impact of Tides and Surges on Fluvial Floods in Coastal Regions." Remote Sensing 14, no. 22 (November 16, 2022): 5779. http://dx.doi.org/10.3390/rs14225779.

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Fluvial floods in coastal areas are affected by tides and storm surges, while the impact is seldom quantified because the dynamics of seawater levels are often not represented in river routing models. This study established a model framework by coupling a surge model with a global hydrodynamic model at a higher spatiotemporal resolution than previous studies so that flood processes affected by seawater level fluctuation in small river basins can be investigated. Model implementation in Zhejiang Province, China, shows that the integration of dynamic seawater levels increases the stress of flooding along the Zhejiang coasts. The ocean effect varies in space, as it is much stronger in northern Zhejiang because of the lower landform and strong tidal amplification, while the mountainous rivers in southern Zhejiang are dominated by river flow regimes. Typhoon Lekima resulted in compound flood events (i.e., rainfall-induced riverine flood, tides, and surges), during which the maximum water level at the outlet of Qiantang River was 0.80 m in the default model settings with a constant downstream seawater level (i.e., 0 m), while it increased to 2.34 m (or 2.48 m) when tides (or tides and surges) were considered. The maximum increase due to tides and surges was 2.09 m and 1.45 m, respectively, while the maximum increase did not match the time of the flood peak. This mismatching indicates the need to consider different processes in physical models rather than linearly summing up different extreme water levels (i.e., river flood, tide, and surge) found in previous studies. The model framework integrating various flow processes will help to prevent risks of compound events in coastal cities in practical and future projections under different scenarios.

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Uddin, Gazi Tamiz, Mahbuba Akther Mishu, Md Tuhinul Hasan, and Debarshi Choudhury. "Crop production amid climate change and river water level fluctuation at northeastern region of Bangladesh: A time series analysis." International Journal of Agricultural Research, Innovation and Technology 12, no. 2 (January 24, 2023): 18–26. http://dx.doi.org/10.3329/ijarit.v12i2.64023.

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The overall goal of this study was to examine the effects of climate change on the yield of four distinct crops (Aus, Aman, Boro and Wheat) in Sylhet by using secondary climate data from 1970 to 2020. The study's other goal is to assess the impact of river water levels on crop productivity in Sylhet over time. Data on crop productivity, weather variability and river water levels were gathered from the various fields. Yield vs. climatic correlation was discovered in the study, and this correlation varied according to season. To estimate the impact of climate change on rice yield, a multiple regression model is used. Climate variables in the model were found to account for 11% of the overall variation in Aus rice yield. The relationship between relative humidity and maximum temperature is positive and statistically significant. Other variables had no effect on yield because they were not significant. Furthermore, Regression results indicated that climate variables account for 60.6 percent of the overall variation in Aman rice output. Relative humidity, on the other hand, can undermine the yield. Climate variables account for 53.5 percent of the overall variation in Boro rice output, according to the findings. As a result, an increase in rainfall may have a negative impact on Boro rice yield. Maximum and minimum temperatures might have a favorable impact on Boro rice yield. Increases in maximum temperature, on the other hand, can considerably boost Wheat yield while decreases in minimum temperature can diminish Wheat yield. On the other side, the results of the regression analysis suggest that river water level has a minor impact on Aus, Aman, and Boro yield. However, as the model demonstrates, the river water level can have an impact on wheat yield. The impact of temperature and rainfall on water level was also investigated in this study because the regression model failed to produce positive results. Surprisingly, the model performs well, despite the fact that maximum temperatures have a negative impact on water levels in the Aus and Aman seasons. This shows that if warmer temperatures aid raises Aus and Aman yields, then the water level cannot sabotage the yield rise. Rainfall has a favorable impact on the water levels in the Aus, Aman, and Boro seasons, but has a negative impact on the water levels in the Wheat season. Int. J. Agril. Res. Innov. Tech. 12(2): 18-26, December 2022

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Nan, Tian, and Wengeng Cao. "Effect of Ecological Water Supplement on Groundwater Restoration in the Yongding River Based on Multi-Model Linkage." Water 15, no. 2 (January 16, 2023): 374. http://dx.doi.org/10.3390/w15020374.

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Evaluating the effect of ecological water supplement on groundwater restoration quantitatively could produce positive contributions to both water cycle theory and surface–groundwater conjunctive management. Therefore, in this paper, a groundwater flow numerical model has been established after calculating the river section seepage rate using a fuzzy mathematical method in the Yongding River channel. The simulated results show that the model could accurately reflect the real groundwater dynamic features. Then, a data-driven random forest(RF) model has been established to quantitatively evaluate the contributions of the factors which influence the groundwater level variation. The Nash-Sutcliffe efficiency coefficient(NSE) of the RF model is 0.93. It shows excellent ability to identify the rising zone of groundwater level. The study shows that the infiltration capacity is strong in the upstream area of the Yongding River, and the seepage rate is over 0.7. The lowest seepage rate is 0.19 at the downstream end, while the seepage rate in the middle area is basically between 0.4 and 0.7. From 2018 to 2019, the ecological water supplement of the Yongding River has played a significant role in raising the groundwater level along the river channel. Additionally, its contribution analyzed by the RF model to the change of groundwater level is 25%. Groundwater exploitation is the most important variable affecting the groundwater level variation. The impact depth of groundwater level fluctuation reaches about 10 m. The impact range where the groundwater level average uplifts 1.86 m is 502.13 km2. The influence direction gradually changes from around the ecological water supplement section to along the Yongding River channel. The groundwater level variation along the tangential direction of the Yongding River is slowing down. The groundwater level would entirely uplift with 170 × 106 m3/year ecological water supplement of the Yongding River and 35.77 × 106 m3/year groundwater mining reduction in the downstream area until 2035.

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Mishra, Ashrut. "Ground Water Level Prediction using Adaptive Neuro-Fuzzy Inference Systems and Simulated Annealing." International Journal for Research in Applied Science and Engineering Technology 10, no. 6 (June 30, 2022): 3366–71. http://dx.doi.org/10.22214/ijraset.2022.44609.

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Abstract: In Indian subcontinent the source of ground water is mainly from rainfall and partially due to the river flow, lakes, and reservoirs, which is highly nonlinear and dynamic. In this paper, the seasonal ground water levels will be predicted using the simulated Annealing (SA) based on previous seasonal rainfall and ground water levels. The study will be carried out in Lucknow district, India. The main objective of this paper is to develop a reliable groundwater level fluctuation forecasting system to generate trend forecasts. The forecasts, based on SA techniques, are then compared to actual measurements recorded during a subsequent monitoring period, for this MATLAB platform will be used for generating the SA codes.

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TANAKA, Hitoshi, Hyun-seok LEE, and Kazuya FURUMICHI. "CHANGE IN TOPOGRAPHY AND WATER LEVEL FLUCTUATION CAUSED BY CONSTRUCTION OF JETTY AT THE SHIRIBETSU RIVER MOUTH." PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN 18 (2002): 461–66. http://dx.doi.org/10.2208/prooe.18.461.

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Zhang, Yang, Long-wei Qiu, Bao-liang Yang, Ji Li, and Ye-lei Wang. "Effects of water level fluctuation on sedimentary characteristics and reservoir architecture of a lake, river dominated delta." Journal of Central South University 23, no. 11 (November 2016): 2958–71. http://dx.doi.org/10.1007/s11771-016-3360-1.

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Rajmohan, N., and L. Elango. "Hydrogeochemistry and its relation to groundwater level fluctuation in the Palar and Cheyyar river basins, southern India." Hydrological Processes 20, no. 11 (2006): 2415–27. http://dx.doi.org/10.1002/hyp.6052.

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Xuan, Weihao, Feng Zhang, Hongye Zhou, Zhenhong Du, and Renyi Liu. "Improving Geographically Weighted Regression Considering Directional Nonstationary for Ground-Level PM2.5 Estimation." ISPRS International Journal of Geo-Information 10, no. 6 (June 15, 2021): 413. http://dx.doi.org/10.3390/ijgi10060413.

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The increase in atmospheric pollution dominated by particles with an aerodynamic diameter smaller than 2.5 μm (PM2.5) has become one of the most serious environmental hazards worldwide. The geographically weighted regression (GWR) model is a vital method to estimate the spatial distribution of the ground-level PM2.5 concentration. Wind information reflects the directional dependence of the spatial distribution, which can be abstracted as a combination of spatial and directional non-stationarity components. In this paper, a GWR model considering directional non-stationarity (GDWR) is proposed. To assess the efficacy of our method, monthly PM2.5 concentration estimation was carried out as a case study from March 2015 to February 2016 in the Yangtze River Delta region. The results indicate that the GDWR model attained the best fitting effect (0.79) and the smallest error fluctuation, the ordinary least squares (OLS) (0.589) fitting effect was the worst, and the GWR (0.72) and directionally weighted regression (DWR) (0.74) fitting effects were moderate. A non-stationarity hypothesis test was performed to confirm directional non-stationarity. The distribution of the PM2.5 concentration in the Yangtze River Delta is also discussed here.

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Zhou, Jian Jun, Zhi Peng Gong, Lei Chen, and Ke Ke Xie. "Mechanism of Muzhuping Landslide to Water Fluctuation and Rainfall in Shuibuya Reservoir." Applied Mechanics and Materials 90-93 (September 2011): 302–6. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.302.

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On May 10, 2007, the Muzhuping landslide moved into Modao-he River caused by impoundment and early rainfall, which is a first landslide hazard in the Shuibuya Reservoir. Using ABAQUS software to analysis the mechanism of deformation with considering the coupling Seepage-stress, and by according to residual thrust method, some predictions of the slope stability were performed with considering to fluctuation of the reservoir water. The numerical results show that the initial impoundment and rapid declining of reservoir water level are most dangerous for a reservoir.

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Hu, Sheng, Jun Xia, Xia Wu, Yingcai Wang, and Fan Xia. "Water Environment Variation in the Three Gorges Tributary and Its Influencing Factors on Different Scales." Water 10, no. 12 (December 12, 2018): 1831. http://dx.doi.org/10.3390/w10121831.

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Long River is a small tributary typical of the Three Gorges Reservoir. In order to clarify the influence of hydro-meteorological factors and human regulation of the reservoir water level on the water environment, we monitored water environment parameters at six sites along Long River for three years, and were able to assess the degree to which variation in the water environment was affected from the micro-scale to macro-scale processes. We found that the water environment parameters have obvious seasonal variation and spatial distribution patterns. From upstream to the estuary, the influence of the backwater was gradually enhanced, whereas the influence of inflow gradually weakened. The distance coefficient between the samples in the backwater area and control sites in the upstream and the Yangtze River had a significant longitudinal gradient pattern (ANOVA, p < 0.05). Through redundancy analysis (RDA) forward selection, we found that cumulative precipitation, water level, cumulative net radiation, daily average temperature, daily net radiation, and daily precipitation all had significant influences on the water environment of the Long River (global permutation test, p < 0.05). The perennial backwater area was mostly affected by water level fluctuations (explaining 39.9% of data variation), whereas the fluctuation backwater area and the upstream inflow area were most affected by cumulative precipitation (explaining 42.9% and 44.0% of data variation, respectively). On the macroscale, the contribution rate of monthly change to the variation of water environment variables reached 54.9%, and the contribution rate of geographical change to the variation of water environment variables was only 7.2%, indicating that the water environment of Long River was mainly affected by exogenous input factors driven by the monsoon climate. Furthermore, we showed that the spatial interpolation method combined with the distance coefficient can easily and efficiently describe the complicated dynamic influences of the upstream inflow and the Yangtze River backwater on the water environment in the Long River bay. The conclusions are helpful in explaining the driving mechanisms of the water environment in the tributaries of the Three Gorges Reservoir, which can provide reference for water environmental protection and management in the Three Gorges Reservoir.

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Xia, Haibin, Hui Wang, and Guangxing Ji. "Regional Inequality and Influencing Factors of Primary PM Emissions in the Yangtze River Delta, China." Sustainability 11, no. 8 (April 15, 2019): 2269. http://dx.doi.org/10.3390/su11082269.

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In recent years, haze pollution has become more and more serious in the Yangtze River Delta (YRD). However, the impact mechanism of socio-economic factors on primary particulate matter (PM) emissions remains unclear. Based on the provincial primary PM emission data in the YRD from 1995 to 2014, this paper used Slope, Theil index, and Stochastic Impacts by Regression on Population, Affluence, and Technology (STIAPAT) models to quantitatively identify the regional differences of primary PM emissions and explore the key influencing factors. The results showed that primary fine particulate matter (PM2.5), inhalable particulate (PM10), and total suspended particulate (TSP) emissions all featured an upward trend of fluctuation over the study period. The regional differences in primary TSP emissions in the YRD region was gradually shrinking and the regional differences of primary PM2.5 and PM10 emissions presented a rising trend of fluctuation. The estimated coefficient of population size, energy structure, and fixed assets investment (FAI) were all significantly positive at the level of 1%. The negative effect of economic growth on energy PM emissions was significant under the level of 1%. The increase of foreign direct investment (FDI) had different effects on primary PM2.5, PM10, and TSP emissions. In addition, the influence of energy intensity on primary PM emission from energy consumption are mainly negative but not significant even under the level of 10%. These conclusions have guiding significance for the formulation of PM emission reduction policy without affecting YRD’s economic development.

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Špoljar, Maria, Tvrtko Dražina, Jasna Lajtner, Goran Kovačević, Ana Pestić, Dora Matijašec, and Tea Tomljanović. "Impact of water level fluctuation in the shaping of zooplankton assemblage in a shallow lake." Croatian Journal of Fisheries 76, no. 1 (March 1, 2018): 27–34. http://dx.doi.org/10.2478/cjf-2018-0003.

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AbstractShallow lakes are strongly affected by global climate changes reflected in significant parameters of ecosystem deterioration, i.e. biodiversity decrease, and water turbidity. Zooplankton research in Škrčev kut oxbow lake (Krapina River watershed, NW Croatia, Europe) was conducted during the summer of 2012 and 2013 with the aim to determine the effect of inter-annual, short-timescale changes of hydrological regime on environmental conditions, macrophytes, zooplankton and fish assemblage within an oxbow lake in the temperate region. Within one-year period the water level increased by 2 meters. This caused a significant reduction of floating-leaved macrophytes (i.e.Nuphar lutea), while turbidity, ortho-phosphate and chlorophyllaconcentrations increased. These altered ecological conditions were reflected in the shift from floating-leaved macrophytes at the lower water level to phytoplankton-dominated lake at the higher water level. Zooplankton underwent significant alteration in assemblage. The results suggest that fish preference suppressed cladocerans and enhanced the rotifer and copepod abundance. Our results indicate that even in a short-timescale zooplankton assemblage mediates in the modification of ecosystem functioning.

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Zeng, Yujin, Zhenghui Xie, Yan Yu, Shuang Liu, Linying Wang, Binghao Jia, Peihua Qin, and Yaning Chen. "Ecohydrological effects of stream–aquifer water interaction: a case study of the Heihe River basin, northwestern China." Hydrology and Earth System Sciences 20, no. 6 (June 16, 2016): 2333–52. http://dx.doi.org/10.5194/hess-20-2333-2016.

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Abstract. A scheme describing the process of stream–aquifer interaction was combined with the land model CLM4.5 to investigate the effects of stream water conveyance over riparian banks on ecological and hydrological processes. Two groups of simulations for five typical river cross sections in the middle reaches of the arid-zone Heihe River basin were conducted. The comparisons between the simulated results and the measurements from water wells, the FLUXNET station, and remote sensing data showed good performance of the coupled model. The simulated riparian groundwater table at a propagation distance of less than 1 km followed the intra-annual fluctuation of the river water level, and the correlation was excellent (R2 = 0.9) between the river water level and the groundwater table at the distance 60 m from the river. The correlation rapidly decreased as distance increased. In response to the variability of the water table, soil moisture at deep layers also followed the variation of river water level all year, while soil moisture at the surface layer was more sensitive to the river water level in the drought season than in the wet season. With increased soil moisture, the average gross primary productivity and respiration of riparian vegetation within 300 m from the river in a typical section of the river increased by approximately 0.03 and 0.02 mg C m−2 s−1, respectively, in the growing season. Consequently, the net ecosystem exchange increased by approximately 0.01 mg C m−2 s−1, and the evapotranspiration increased by approximately 3 mm day−1. Furthermore, the length of the growing season of riparian vegetation also increased by 2–3 months due to the sustaining water recharge from the river. Overall, the stream–aquifer water interaction plays an essential role in the controlling of riparian hydrological and ecological processes.

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Paradava, D. M., and H. D. Rank. "Groundwater Resources as Influenced by Climatic Change in Shetrunji basin of Gujarat State, India." Current World Environment 10, no. 3 (December 25, 2015): 994–1003. http://dx.doi.org/10.12944/cwe.10.3.31.

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The estimation of climatic alteration influencing on groundwater recharge will help to prepare a future plan for groundwater development and management planning for the basin. It will also be helpful for agriculture as well as other resource planning. The required shift in cropping pattern can also be judged. The study was undertaken for Shetrunji river basin having an area of 5646.98 km2. The entire area was found consisting of 17 watersheds. The climate change impact on Rainfall, Runoff and estimated groundwater recharge by 3 different methods were assessed. The groundwater recharge varied from 3.11% to 49.28%, 0% to 15.34% and 0.72% to 14.62% of rainfall by water balance, Krishna Rao (1970) and water table variation respectively. The climate change impacts favors to increase the rainfall significantly in 6 out of 17 watersheds while the runoff is found increasing in 5 out of 17 watersheds of the basin. The rainfall and runoff was influenced by the climate change in Northern part of upper reach and southernmost part of middle reach of basin. The area weighted rainfall of the Shetrunji river basin was found increasing significantly. The areal mean depth of monsoon runoff for entire Shetrunji basin was increasing significantly at the rate of 17.7 mm per decade. The groundwater recharge assessed by water balance method was found higher as compared to Krishna Rao (1970) and water level fluctuation method. The groundwater recharge expected by water balance, Krishna Rao (1970) and water level fluctuation methods is found to be enlarged in 13, 9 and 6 watersheds out of 17 watershed of the basin. The areal mean depth of groundwater recharge in Shetrunji basin during monsoon season in water level fluctuation method was found increasing significantly at the rate of 13.01 mm per decade due to climate change impacts.

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Journal articles on the topic 'River level fluctuation'

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