scholarly journals Spatiotemporal Dynamics of Nitrogen Transport in the Qiandao Lake Basin, a Large Hilly Monsoon Basin of Southeastern China

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1075 ◽  
Author(s):  
Dongqiang Chen ◽  
Hengpeng Li ◽  
Wangshou Zhang ◽  
Steven G. Pueppke ◽  
Jiaping Pang ◽  
...  
Keyword(s):  
Assessment Tool ◽  
Spatiotemporal Dynamics ◽  
Transport Processes ◽  
Vegetation Coverage ◽  
Lake Basin ◽  
Spatial Effects ◽  
Source Attribution ◽  
Transport Pathway ◽  
Southeastern China ◽  
Credible Information

The Qiandao Lake Basin (QLB), which occupies low hilly terrain in the monsoon region of southeastern China, is facing serious environmental challenges due to human activities and climate change. Here, we investigated source attribution, transport processes, and the spatiotemporal dynamics of nitrogen (N) movement in the QLB using the Soil and Water Assessment Tool (SWAT), a physical-based model. The goal was to generate key localized vegetative parameters and agronomic variables to serve as credible information on N sources and as a reference for basin management. The simulation indicated that the basin’s annual average total nitrogen (TN) load between 2007 and 2016 was 11,474 tons. Steep slopes with low vegetation coverage significantly influenced the spatiotemporal distribution of N and its transport process. Monthly average TN loads peaked in June due to intensive fertilization of tea plantations and other agricultural areas and then dropped rapidly in July. Subsurface flow is the key transport pathway, with approximately 70% of N loads originating within Anhui Province, which occupies just 58% of the basin area. The TN yields of sub-basins vary considerably and have strong spatial effects on incremental loads entering the basin’ major stream, the Xin’anjiang River. The largest contributor to N loads was domestic sewage (21.8%), followed by livestock production (20.8%), cropland (18.6%), tea land (15.5%), forest land (10.9%), atmospheric deposition (5.6%), orchards (4.6%), industry (1.4%), and other land (0.8%). Our simulation underscores the urgency of increasing the efficiency of the wastewater treatment, conserving slope land, and optimizing agricultural management as components of a comprehensive policy to control N pollution in the basin.

scholarly journals Hydrologic evaluation and effects of climate change on the Nong Han Lake Basin, northeastern Thailand

2019 ◽  
Vol 11 (4) ◽  
pp. 992-1000
Author(s):  
Jirawat Supakosol ◽  
Kowit Boonrawd
Keyword(s):  
Climate Change ◽  
Assessment Tool ◽  
Swat Model ◽  
Climate Projections ◽  
Lake Basin ◽  
Model Soil ◽  
Regional Climates ◽  
Water Assessment ◽  
Effective Water ◽  
Northeastern Thailand

Abstract The purpose of this study is to investigate the future runoff into the Nong Han Lake under the effects of climate change. The hydrological model Soil and Water Assessment Tool (SWAT) has been selected for this study. The calibration and validation were performed by comparing the simulated and observed runoff from gauging station KH90 for the period 2001–2003 and 2004–2005, respectively. Future climate projections were generated by Providing Regional Climates for Impacts Studies (PRECIS) under the A2 and B2 scenarios. The SWAT model yielded good results in comparison to the baseline; moreover, the results of the PRECIS model showed that both precipitations and temperatures increased. Consequently, the amount of runoff calculated by SWAT under the A2 and B2 scenarios was higher than that for the baseline. In addition, the amount of runoff calculated considering the A2 scenario was higher than that considering the B2 scenario, due to higher average annual precipitations in the former case. The methodology and results of this study constitute key information for stakeholders, especially for the development of effective water management systems in the lake, such as designing a rule curve to cope with any future incidents.

scholarly journals Assessment of soil erosion in the Dongting Lake Basin, China: Patterns, drivers, and implications

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261842
Author(s):  
Jianyong Xiao ◽  
Binggeng Xie ◽  
Kaichun Zhou ◽  
Shana Shi ◽  
Junhan Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Soil Erosion ◽  
Human Activities ◽  
Dongting Lake ◽  
Vegetation Coverage ◽  
Lake Basin ◽  
Driving Mechanism ◽  
Land Use Types ◽  
Key Factor

Soil loss caused by erosion is a global problem. Therefore, the assessment of soil erosion and the its driving mechanism are of great significance to soil conservation. However, soil erosion is affected by both climate change and human activities, which have not been quantified, and few researchers studied the differences in the driving mechanisms of soil erosion depending on the land use type. Therefore, the spatiotemporal characteristics and changing trends of soil erosion in the Dongting Lake Basin were analyzed in this study. Geographic detectors were used to identify the dominant factors affecting soil erosion in different land use types. In this study, a sensitivity experiment was conducted to clarify the relative contributions of climate change and human activities to soil erosion changes. In addition, we studied the effects of different land use types and vegetation cover restoration on soil erosion. The results show that soil erosion in the Dongting Lake Basin decreased from 2000 to 2018. Human activities represented by land use types and vegetation coverage significantly contributed to the alleviation of soil erosion in the Dongting Lake Basin, whereas climate change represented by rainfall slightly aggravated soil erosion in the study area. The restoration of grassland vegetation and transfer of cultivated land to woodlands in the study area improved the soil erosion. The slope steepness is the key factor affecting the intensity of soil erosion in dry land, paddy fields, and unused land, whereas the vegetation coverage is the key factor affecting the intensity of soil erosion in woodland, garden land, and grassland. Detailed spatiotemporally mapping of soil erosion was used to determine the connections between soil erosion and potential drivers, which have important implications for vegetation restoration and the optimization of land use planning.

scholarly journals Runoff sensitivity to climate and land-use changes: A case study in the Longtan basin, Southwestern China

2020 ◽  
Author(s):  
Guiyan Mo ◽  
Ya Huang ◽  
Qing Yang ◽  
Dayang Wang ◽  
Chongxun Mo
Keyword(s):  
Land Use ◽  
Water Conservation ◽  
Assessment Tool ◽  
Land Use Changes ◽  
Annual Runoff ◽  
Vegetation Coverage ◽  
Average Annual Runoff ◽  
Annual Evaporation ◽  
Water Assessment

Abstract Based on the scenario hypothesis method, this paper applied a Soil and Water Assessment Tool (SWAT) to analyze the sensitivity of runoff to climate and land-use changes in the Longtan basin, China. Results indicated that (1) for every 1 °C increase in temperature, the average annual runoff decreased by 9.9 mm, and the average annual evaporation increased by 9.3 mm. However, for every 10% increase in rainfall, the average annual runoff and evapotranspiration increased by 96.3 mm and 11.53 mm, respectively. Obviously, runoff was more sensitive to the change in rainfall than temperature in the Longtan basin. Meanwhile, (2) forestland could conserve water resources, but its water consumption was larger. Although grassland played a relatively small role in water conservation, it consumed less water. At the same time, increasing the area of forestland and grassland could weaken peak floods, and the water retention function of vegetation could prevent runoff from increasing and decreasing steeply. Therefore, it is worth improving vegetation coverage.

EFFECTIVNESS OF SOIL AND WATER ASSESSMENT TOOL MODEL TO SIMULATE WATER FLOW IN A LARGE AGRICULTURAL COMPLEX WATERSHED: CASE OF BUYO LAKE BASIN, WEST OF COTE D'IVOIRE

2014 ◽  
Vol 13 (7) ◽  
pp. 1735-1742 ◽  
Author(s):  
Gabriel Lazar ◽  
Tanoh Jean-Jacques Koua ◽  
Jean Patrice Jourda ◽  
Kan Jean Kouame ◽  
Kouao Armand Anoh ◽  
...  
Keyword(s):  
Water Flow ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Assessment Tool ◽  
Lake Basin ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Water Assessment ◽  
Soil And Water

scholarly journals Stream flow simulation and verification in ungauged zones by coupling hydrological and hydrodynamic models: a case study of the Poyang Lake ungauged zone

2017 ◽  
Vol 21 (11) ◽  
pp. 5847-5861 ◽  
Author(s):  
Ling Zhang ◽  
Jianzhong Lu ◽  
Xiaoling Chen ◽  
Dong Liang ◽  
Xiaokang Fu ◽  
...  
Keyword(s):  
Water Resource ◽  
Stream Flow ◽  
Assessment Tool ◽  
Poyang Lake ◽  
Swat Model ◽  
Water Yield ◽  
Lake Basin ◽  
Observation Data ◽  
Wet Season ◽  
Annual Water

Abstract. To solve the problem of estimating and verifying stream flow without direct observation data, we estimated stream flow in ungauged zones by coupling a hydrological model with a hydrodynamic model, using the Poyang Lake basin as a test case. To simulate the stream flow of the ungauged zone, we built a soil and water assessment tool (SWAT) model for the entire catchment area covering the upstream gauged area and ungauged zone, and then calibrated the SWAT model using the data in the gauged area. To verify the results, we built two hydrodynamic scenarios (the original and adjusted scenarios) for Poyang Lake using the Delft3D model. In the original scenario, the upstream boundary condition is the observed stream flow from the upstream gauged area, while, in the adjusted scenario, it is the sum of the observed stream flow from the gauged area and the simulated stream flow from the ungauged zone. The experimental results showed that there is a stronger correlation and lower bias (R2 = 0.81, PBIAS  =  10.00 %) between the observed and simulated stream flow in the adjusted scenario compared to that (R2 = 0.77, PBIAS  =  20.10 %) in the original scenario, suggesting the simulated stream flow of the ungauged zone is reasonable. Using this method, we estimated the stream flow of the Poyang Lake ungauged zone as 16.4 ± 6.2 billion m3 a−1, representing ∼ 11.24 % of the annual total water yield of the entire watershed. Of the annual water yield, 70 % (11.48 billion m3 a−1) is concentrated in the wet season, while 30 % (4.92 billion m3 a−1) comes from the dry season. The ungauged stream flow significantly improves the water balance with the closing error decreased by 13.48 billion m3 a−1 (10.10 % of the total annual water resource) from 30.20 ± 9.1 billion m3 a−1 (20.10 % of the total annual water resource) to 16.72 ± 8.53 billion m3 a−1 (10.00 % of the total annual water resource). The method can be extended to other lake, river, or ocean basins where observation data is unavailable.

scholarly journals Mechanisms and functional features of polarized membrane traffic in epithelial and hepatic cells

1998 ◽  
Vol 336 (2) ◽  
pp. 257-269 ◽  
Author(s):  
Mirjam M. P. ZEGERS ◽  
Dick HOEKSTRA
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Transport Processes ◽  
Protein Kinase Activity ◽  
Transport Pathway ◽  
Hepatic Cells ◽  
Functional Features ◽  
Specific Lipid

Epithelial cells express plasma-membrane polarity in order to meet functional requirements that are imposed by their interaction with different extracellular environments. Thus apical and basolateral membrane domains are distinguished that are separated by tight junctions in order to maintain the specific lipid and protein composition of each domain. In hepatic cells, the plasma membrane is also polarized, containing a sinusoidal (basolateral) and a bile canalicular (apical)-membrane domain. Relevant to the biogenesis of these domains are issues concerning sorting, (co-)transport and regulation of transport of domain-specific membrane components. In epithelial cells, specific proteins and lipids, destined for the apical membrane, are sorted in the trans-Golgi network (TGN), which involves their sequestration into cholesterol/sphingolipid ‘rafts ’, followed by ‘direct ’ transport to the apical membrane. In hepatic cells, a direct apical transport pathway also exists, as revealed by transport of sphingolipids from TGN to the apical membrane. This is remarkable, since in these cells numerous apical membrane proteins are ‘indirectly ’ sorted, i.e. they are first transferred to the basolateral membrane prior to their subsequent transcytosis to the apical membrane. This raises intriguing questions as to the existence of specific lipid rafts in hepatocytes. As demonstrated in studies with HepG2 cells, it has become evident that, in hepatic cells, apical transport pathways can be regulated by protein kinase activity, which in turn modulates cell polarity. Finally, an important physiological function of hepatic cells is their involvement in intracellular transport and secretion of bile-specific lipids. Mechanisms of these transport processes, including the role of multidrug-resistant proteins in lipid translocation, will be discussed in the context of intracellular vesicular transport. Taken together, hepatic cell systems provide an important asset to studies aimed at elucidating mechanisms of sorting and trafficking of lipids (and proteins) in polarized cells in general.

scholarly journals Theoretical Hydrokinetic Power Potential Assessment of the U-Tapao River Basin Using GIS

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1749
Author(s):  
Fida Ali ◽  
Chatchawin Srisuwan ◽  
Kuaanan Techato ◽  
Adul Bennui ◽  
Tanita Suepa ◽  
...  
Keyword(s):  
River Basin ◽  
New Technologies ◽  
Assessment Tool ◽  
Model Performance ◽  
Coefficient Of Determination ◽  
Lake Basin ◽  
Discharge Data ◽  
Flow Estimation ◽  
Southern Thailand ◽  
Water Assessment

Conventional hydropower technologies such as dams have been criticized due to their negative environmental effects which have necessitated the development of new technologies for sustainable development of hydropower energy. Hydrokinetic (HK) energy is one such emerging renewable energy technology and, in this study, a theoretical potential assessment was done using a Geographic Information System (GIS) and Soil and Water Assessment Tool (SWAT) hydrological model, for the U-Tapao river basin (URB), a major tributary of the Songkhla lake basin (SLB) in southern Thailand. The SWAT was calibrated and validated with SWAT calibration and uncertainty (SWAT-CUP)-SUFI 2 programs using the observed discharge data from the gauging stations within the watershed. The model performance was evaluated based on the Nash–Sutcliffe efficiency (NSE) and the coefficient of determination (R2) values, achieving 0.62 and 0.60, respectively, for calibration, and 0.65 and 0.68 for validation which is considered acceptable and can be used to represent flow estimation. The theoretical HK potential was estimated to be 71.9 MW along the 77.18 km U-Tapao river, which could be developed as a renewable and reliable energy source for the communities living around the river. The method developed could also be applied to river systems around the world for resource and time efficient HK potential assessments.

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