scholarly journals A Model Study of the Discharges Effects of Kaidu River on the Salinity Structure of Bosten Lake

Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 8 ◽  
Author(s):  
Ying Liu ◽  
Anming Bao ◽  
Xi Chen ◽  
Ruisen Zhong

The salinization of Bosten Lake, which is the largest lake in the arid or semi-arid region of Xinjiang, has increased. To study the effects of the inflow change of Kaidu River, the main recharge, on the salinity structure of Bosten Lake, the Estuarine, Coastal, and Ocean Modeling System with Sediments (ECOMSED), a basic three-dimensional numerical model, was used. The model is forced by realistic atmospheric forcing and river inflows, and verified by observational data. The model simulations can map the lake water movement processes and offer an understanding of the likely role of river runoff on the Bosten Lake salinity structure. The water mainly flows eastward at the surface and westward at the bottom. The river runoff of Kaidu River significantly affects the salinity structure of the southwestern part of the lake. The Kaidu River discharge mostly flowed northeastward along the west bank of the lake, so with decreasing Kaidu River discharge, the salinity of the region from the inlet of the river to its right (looking in the direction of the flow) subsequently increased. This study helps to the mastering of the dynamic change of salinity and provides some quantity information for controlling the salinization of Bosten Lake.

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 40 ◽  
Author(s):  
Ying Liu ◽  
Anming Bao

Lake water salinization in arid areas is a common problem and should be controlled for the better use of freshwater of lakes and for the protection of the environment around lakes. It is well known that the increasing of hydraulic connectivity improves water quality, but for a lake, understanding how hydraulic connectivity changes its water quality in terms of spatial aspects is of great significance for the protection and utilization of different regions of the lake water body. In this paper, the impacts of three connectivity scenarios on the spatial-temporal salinity changes in Bosten Lake were modeled through the three-dimensional (3D) hydrodynamic model, Environmental Fluid Dynamics Code (EFDC). The constructed Bosten Lake EFDC model was calibrated for water level, temperature, and salinity with acceptable results. As for the Bosten Lake, three connectivity scenarios were selected: (1) the increasing of the discharge water amount into the lake from the Kaidu River, (2) the transferring of 1 million cubic meter freshwater to the southwestern part of the lake (the Huangshuigou region of the lake), and (3) the changing of the outflow position from the southwestern part of the lake (the Kongque river) to the southeastern of the lake (the Caohu region). Through the simulations, we found that the region of the lake mainly influenced by the three scenarios presented here were different, and of the three scenarios, scenario 3 was the best means of controlling the overall lake salinity. On the basis of the salinity distribution results gained from the simulations, decision-makers can choose the ways to mitigate the salinity of the lake according to which region they want to improve the most in terms of economic efficiency and preserve in terms of ecological balance.


2014 ◽  
Vol 69 (6) ◽  
pp. 1334-1343 ◽  
Author(s):  
Shasha Lu ◽  
Ruijie Li ◽  
Xiaoming Xia ◽  
Jun Zheng

Measuring pollutant concentrations in major tributaries is the standard method for establishing pollutant fluxes to the sea. However, this method is costly and difficult, and may be subject to a great deal of uncertainty due to the presence of unknown sources. This uncertainty presents challenges to managers and scientists in reducing contaminant discharges to water bodies. As one less costly method, a three-dimensional model was developed and used to predict pollutant fluxes to the sea. The sorptive contaminant model was incorporated into hydrodynamic and sediment models. Adsorption–desorption of copper by sediments in the Oujiang estuary were described using Henry's law. The model was validated using measured data for water surface elevations, flow velocity/direction, suspended sediment concentrations, and the proportion of copper sorbed to sediment. The validated model was then applied to predict fluxes of copper. Combined with the measured data, the copper concentration in the Oujiang River discharge was calculated as 13.0 μg/L and copper fluxes were calculated as 52 t in 2010. This copper flux prediction was verified using measured dissolved copper concentrations. Comparisons between the modeled and measured results showed good agreement at most stations, demonstrating that copper flux prediction in the Oujiang estuary was reasonably accurate.


2021 ◽  
Author(s):  
Genjiu Wang ◽  
Dandan Hu ◽  
Qianyao Li

Abstract It is generally believed that Cretaceous bioclastic limestone in Mesopotamia basin in central and southern Iraq is a typical porous reservoir with weak fracture development. Therefore, previous studies on the fracture of this kind of reservoir are rare. As a common seepage channel in carbonate rock, fracture has an important influence on single well productivity and waterflooding development of carbonate reservoir. Based on seismic, core and production data, this study analyzes the development characteristics of fractures from various aspects, and discusses the influence of fractures on water injection development of reservoirs. Through special processing of seismic data, it is found that there are a lot of micro fractures in Cretaceous bioclastic limestone reservoir. Most of these micro fractures are filled fractures without conductivity under the original reservoir conditions. However, with the further development of the reservoir, the reservoir pressure, oil-water movement, water injection and other conditions have changed, resulting in the original reservoir conditions of micro fractures with conductivity. The water cut of many production wells in the high part of reservoir rises sharply. In order to describe the three-dimensional spatial distribution of fractures, the core data is used to verify the seismic fracture distribution data volume. After the verification effect is satisfied, the three-dimensional fracture data volume is transformed into the geological model to establish the permeability field including fracture characteristics. The results of numerical simulation show that water mainly flows into the reservoir through high angle micro fractures. Fractures are identified by seismic and fracture model is established to effectively recognize the influence of micro fractures on water injection development in reservoir development process, which provides important guidance for oilfield development of Cretaceous bioclastic limestone reservoir in the central and southern Iraq fields.


2015 ◽  
Vol 12 (16) ◽  
pp. 13793-13817 ◽  
Author(s):  
Z. T. Yu ◽  
X. J. Wang ◽  
E. L. Zhang ◽  
C. Y. Zhao ◽  
H. Y. Lan

Abstract. Lake sediment is an important carbon reservoir. However, little is known on the dynamics and sources of sediment organic carbon in the Bosten Lake. We collected 13 surface (0–2 cm) sediment samples in the Bosten Lake and analyzed total organic carbon (TOC), total nitrogen (TN), stable carbon isotopic composition in TOC (δ13Corg) and grain size. We found a large spatial variability in TOC content (1.8–4.4 %) and δ13Corg value (−26.77 to −23.98 ‰). Using a three end member mixing model with measured TOC : TN ratio and δ13Corg, we estimated that 54–90 % of TOC was from autochthonous sources. Higher TOC content (> 3.7 %) was found in the east and central-north sections and near the mouth of the Kaidu River, which was attributable to allochthonous, autochthonous plus allochthonous, and autochthonous sources, respectively. The lowest TOC content was found in the mid-west section, which might be a result of high kinetic energy levels. Our study indicated that the spatial distribution of sediment TOC in the Bosten Lake was influenced by multiple and complex processes.


2016 ◽  
Vol 46 (5) ◽  
pp. 1633-1656 ◽  
Author(s):  
Qianqian Liu ◽  
Lewis M. Rothstein ◽  
Yiyong Luo

AbstractBuoyant discharge of freshwater from Long Island Sound (LIS) forms a seasonal buoyant plume outside Block Island Sound (BIS) between the coast of Long Island and the denser shelf waters. The plume’s seasonal variability and its response to tides, winds, and surface heating are investigated through a series of process-oriented experiments using the Regional Ocean Modeling System (ROMS). Results show the importance of river discharge, wind directions, and surface heating in the seasonal variation of the BIS buoyant plume. In winter and spring, the plume is intermediate with a large surface offshore extension detached from the bottom. From winter to spring, the river discharge increases; meanwhile, upwelling-favorable winds keep dominating. They compete with the increase of surface heating and generate a broader buoyant plume in spring than in winter. In summer, the plume is bottom advected with most of its width in contact with the bottom and is featured with the steepest isopycnals and narrowest plume, which is driven by a combination of strong insolation, weak buoyant discharge from LIS, and feeble winds. In fall, although the river discharge is comparable to that in winter, the upwelling-favorable wind is relatively weaker, corresponding to a narrower intermediate plume.


2012 ◽  
Vol 44 (3) ◽  
pp. 554-569 ◽  
Author(s):  
Elga Apsīte ◽  
Ilze Rudlapa ◽  
Inese Latkovska ◽  
Didzis Elferts

The study deals with turn-of-the-century changes in the total annual river runoff distribution and high and low flows in Latvia, covering river basins within four hydrological districts which vary according to size and physiographical conditions. Mathematical statistical methods were applied in the analysis of river discharge data series for two study periods of 1951–2009 and 1881–2009. The present results confirm the basic statement concerning the Baltic countries that major significant changes in river runoff during the last two decades have occurred between spring (decrease) and winter (increase) seasons. Mostly insignificant changes in summer runoff and significant/insignificant changes in autumn runoff were found. Analysis shows that a statistically significant trend of increase in low flow for the cold period and a significant trend of decrease in the high discharge and coefficient d of uneven runoff distribution were detected. Changes in river hydrological regime are mainly caused by changes in large-scale atmospheric circulation processes following climate warming, which has taken place. Latvian river hydrography has therefore changed and become more similar to Western European rivers.


2000 ◽  
Vol 4 (1) ◽  
pp. 65-78 ◽  
Author(s):  
H. Koivusalo ◽  
T. Karvonen ◽  
A. Lepistö

Abstract. Runoff generation in a forested catchment (0.18 km2) was simulated using a quasi-three-dimensional rainfall-runoff model. The model was formulated over a finite grid where water movement was assumed to be dominantly vertical in the unsaturated soil zone and horizontal in the saturated soil. The vertical soil moisture distribution at each grid cell was calculated using a conceptual approximation to the one-dimensional Richards equation. The approximation allowed the use of a simple soil surface boundary condition and an efficient solution to the water table elevation over the finite grid. The approximation was coupled with a two-dimensional ground water model to calculate lateral soil water movement between the grid cells and exfiltration over saturated areas, where runoff was produced by the saturation-excess mechanism. Runoff was an input to a channel network, which was modelled as a nonlinear reservoir. The proposed approximation for the vertical soil moisture distribution in unsaturated soil compared well to a numerical solution of the Richards equation during shallow water table conditions, but was less satisfactory during prolonged dry periods. The simulation of daily catchment outflow was successful with the exception of underprediction of extremely high peak flows. The calculated water table depth compared satisfactorily with the measurements. An overall comparison with the earlier results of tracer studies indicated that the modelled contribution of direct rainfall/snowmelt in streamflow was higher than the isotopically traced fraction of event-water in runoff. The seasonal variation in the modelled runoff-contributing areas was similar to that in the event-water-contributing areas from the tracer analysis.


2020 ◽  
Vol 24 (3) ◽  
pp. 1447-1465 ◽  
Author(s):  
Johannes Riegger

Abstract. The knowledge of water storage volumes in catchments and in river networks leading to river discharge is essential for the description of river ecology, the prediction of floods and specifically for a sustainable management of water resources in the context of climate change. Measurements of mass variations by the GRACE gravity satellite or by ground-based observations of river or groundwater level variations do not permit the determination of the respective storage volumes, which could be considerably bigger than the mass variations themselves. For fully humid tropical conditions like the Amazon the relationship between GRACE and river discharge is linear with a phase shift. This permits the hydraulic time constant to be determined and thus the total drainable storage directly from observed runoff can be quantified, if the phase shift can be interpreted as the river time lag. As a time lag can be described by a storage cascade, a lumped conceptual model with cascaded storages for the catchment and river network is set up here with individual hydraulic time constants and mathematically solved by piecewise analytical solutions. Tests of the scheme with synthetic recharge time series show that a parameter optimization either versus mass anomalies or runoff reproduces the time constants for both the catchment and the river network τC and τR in a unique way, and this then permits an individual quantification of the respective storage volumes. The application to the full Amazon basin leads to a very good fitting performance for total mass, river runoff and their phasing (Nash–Sutcliffe for signals 0.96, for monthly residuals 0.72). The calculated river network mass highly correlates (0.96 for signals, 0.76 for monthly residuals) with the observed flood area from GIEMS and corresponds to observed flood volumes. The fitting performance versus GRACE permits river runoff and drainable storage volumes to be determined from recharge and GRACE exclusively, i.e. even for ungauged catchments. An adjustment of the hydraulic time constants (τC, τR) on a training period facilitates a simple determination of drainable storage volumes for other times directly from measured river discharge and/or GRACE and thus a closure of data gaps without the necessity of further model runs.


2015 ◽  
Vol 12 (22) ◽  
pp. 6605-6615 ◽  
Author(s):  
Z. T. Yu ◽  
X. J. Wang ◽  
E. L. Zhang ◽  
C. Y. Zhao ◽  
X. Q. Liu

Abstract. Lake sediment is an important carbon reservoir. However, little is known on the dynamics and sources of sediment organic carbon in Bosten Lake. We collected 13 surface (0–2 cm) sediment samples in Bosten Lake and analyzed total organic carbon (TOC), total nitrogen (TN), stable carbon isotopic composition in TOC (δ13Corg), and grain size. We found a large spatial variability in TOC content (1.8–4.4 %) and δ 13Corg value (−26.77 to −23.98 ‰). Using a three-end-member mixing model with measured TOC : TN ratio and δ13Corg, we estimated that 54–90 % of TOC was from autochthonous sources. Higher TOC content (> 3.7 %) was found in the east and central-north sections and near the mouth of the Kaidu River, which was attributable to allochthonous, autochthonous plus allochthonous, and autochthonous sources, respectively. The lowest TOC content was found in the mid-west section, which might be a result of high kinetic energy levels. Our study indicated that the spatial distribution of sediment TOC in the Bosten Lake was influenced by multiple and complex processes.


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