Spatiotemporal distribution of nitrous oxide ( N 2 O ) emissions from cascade reservoirs in Lancang‐Mekong River Yunnan section, Southwestern China

2020 ◽  
Author(s):  
Wei Wu ◽  
Jiawei Wang ◽  
Xiaode Zhou ◽  
Bo Yuan ◽  
Mengjing Guo ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Spatiotemporal Distribution ◽  
Mekong River ◽  
Southwestern China ◽  
Cascade Reservoirs

Nitrate leaching, direct and indirect nitrous oxide fluxes from sloping cropland in the purple soil area, southwestern China

2012 ◽  
Vol 162 ◽  
pp. 361-368 ◽  
Author(s):  
Minghua Zhou ◽  
Bo Zhu ◽  
Klaus Butterbach-Bahl ◽  
Tao Wang ◽  
Jessica Bergmann ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrate Leaching ◽  
Southwestern China ◽  
Purple Soil ◽  
Soil Area

Nitrous oxide emissions from cascade hydropower reservoirs in the upper Mekong River

2020 ◽  
Vol 173 ◽  
pp. 115582 ◽  
Author(s):  
Wenqing Shi ◽  
Qiuwen Chen ◽  
Jianyun Zhang ◽  
Dongsheng Liu ◽  
Qitao Yi ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Mekong River ◽  
Nitrous Oxide Emissions ◽  
Hydropower Reservoirs

scholarly journals Response of phytoplankton to banana cultivation: A case study of Lancang-Mekong River, southwestern China

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Juan Dai ◽  
Yinjun Zhou ◽  
Haipeng Wu ◽  
Yunchao Zhang ◽  
Kongxian Zhu
Keyword(s):  
Mekong River ◽  
Southwestern China

Control of the Hydraulic Load on Nitrous Oxide Emissions from Cascade Reservoirs

2019 ◽  
Vol 53 (20) ◽  
pp. 11745-11754 ◽  
Author(s):  
Xia Liang ◽  
Tao Xing ◽  
Junxiong Li ◽  
Baoli Wang ◽  
Fushun Wang ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrous Oxide Emissions ◽  
Cascade Reservoirs ◽  
Hydraulic Load

scholarly journals Spatiotemporal Variability of the Nitrous Oxide Concentrations and Fluxes From a Cascaded Dammed River

2021 ◽  
Vol 9 ◽  
Author(s):  
Shengnan Wu ◽  
Xiaofeng Wang ◽  
Tingting Liu ◽  
Yixin He ◽  
Ziyi Que ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Residence Time ◽  
Energy Demand ◽  
Local Variation ◽  
Spatiotemporal Patterns ◽  
Spatiotemporal Variability ◽  
Hydraulic Residence Time ◽  
Cascade Reservoirs ◽  
Chl A ◽  
River Reservoir

Rivers have been largely considered as the source of nitrous oxide (N2O) to the atmosphere. N2O emissions from rivers could be seriously influenced by damming and exhibit unique spatiotemporal patterns in river-reservoir systems. Multiple research studies report N2O emissions from rivers with single reservoirs, but the spatiotemporal patterns and controls of N2O emissions from cascaded river-reservoir system remain unclear. In this study, we investigated the spatiotemporal variations of N2O concentrations and fluxes along a cascade damming river (Wubu River) in Southwest China. Our results showed that N2O concentrations in the Wubu River ranged from 2.5 to 283.2 nmol L−1 with a mean of 50.7 ± 52.3 nmol L−1 and were generally supersaturated with gas fluxes ranging from 11.8 to 805.6 μmol m−2 d−1. N2O concentrations and fluxes showed a significant longitudinal variation with increasing fluxes from upstream to downstream. Meanwhile, for each river-reservoir-released water continuum, local variation of N2O concentrations was also prominent. Reservoir sections and released water sections had 2.7 (1.2–7.9) and 3.4 (1.3–12.2) times higher N2O concentrations than the corresponding upstream river reaches and acted as hotpots for N2O emission. The N2O concentrations had significant correlations with organic carbon, phosphorus, and Chl-a in surface water. Furthermore, the N2O concentrations and fluxes in reservoirs had a significant correlation with hydraulic residence time and hydraulic load, suggesting that fragmentation of hydrologic conditions was an important driver for the spatial variations of N2O concentrations in the Wubu River cascade reservoirs. Our results suggested that hydraulic residence time could predict the variation pattern of N2O fluxes in this small river basin. Seasonal variations of N2O concentrations and fluxes were the highest in autumn and lowest in winter and were mainly attributed to temperature and rainfall. N2O fluxes were much higher in the Wubu River than the average levels of China’s reservoirs and global reservoirs, acting as enhanced N2O emitter. Our study highlighted that the cascade reservoirs not only act as exciters for N2O production and emissions but also form cumulative effects and local hotpots along the longitudinal dimension, which could significantly increase the complexity of the spatiotemporal variability in riverine N2O emissions. Given the increasing construction of new river dams due to growing energy demand, more research should be done to quantify the contribution of cascaded damming to riverine N2O budgets.

scholarly journals Seasonal regulation of river discharge by the cascade reservoirs in the Lancang River and its effect on downstream freshwater and estuarine saltwater intrusion

2021 ◽  
Vol 4 (1) ◽  
pp. 233-250
Author(s):  
Jianrong Zhu ◽  
Wei Qiu ◽  
Chuanmin Tang ◽  
Xinyue Cheng
Keyword(s):  
River Discharge ◽  
Saltwater Intrusion ◽  
Three Dimensional ◽  
Dry Season ◽  
Mekong River ◽  
Cascade Reservoirs ◽  
Lancang River ◽  
Seasonal Regulation ◽  
Sand Bar ◽  
Hydrological Station

This study assesses the seasonal regulation of river discharge by hydropower dam-induced cascade reservoirs in the Lancang River and its effect on downstream freshwater and estuarine saltwater intrusion. There are eight main reservoirs in the Lancang River, with a total regulation capacity of 25.67 billion m3, which regulates river discharge by conserving water in the flood season and releasing water in the dry season. River discharge during the dry season from 1960 to 2009 accounted for 21% of the annual discharge before the cascade reservoirs were constructed and increased to 33% from 2010 to 2015 after the cascade reservoirs were constructed at the Jinghong hydrological station, which is the lowermost station in the Lancang River. During the 2016 extreme drought in the lower Mekong River basin, the river discharge increased by 550, 367, 1283, 969, and 524 m3/s in January, February, March, April, and May, respectively, regulated by the cascade reservoirs at the Jinghong hydrological station. Considering runoff, tides, wind, and continental shelf currents, a high-resolution three-dimensional numerical model was used to simulate the effect of regulation of river discharge by the cascade reservoirs in the Lancang River on the saltwater intrusion in the Mekong River Delta (MRD). The simulation results show that the seasonal regulation of river discharge by the cascade reservoirs in the Lancang River weakens estuarine saltwater intrusion during the dry season, especially in the sand bar areas, which is much more significant in the extreme dry season of 2016. The seasonal regulation of river discharge by the reservoirs in the Lancang River makes the seasonal distribution of downstream river discharge more uniform, favoring downstream freshwater utilization and alleviating flood disasters and saltwater intrusion in the MRD.

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