Shallow Groundwater Movement in the Skagit River Delta Area, Skagit County, Washington

2009 ◽  
Author(s):  
Mark E. Savoca ◽  
Kenneth H. Johnson ◽  
Elisabeth T. Fasser
Keyword(s):  
Shallow Groundwater ◽  
River Delta ◽  
Delta Area ◽  
Groundwater Movement ◽  
Skagit River

Toxaphene levels in retail food from the Pearl River Delta area of South China and an assessment of dietary intake

Chemosphere ◽  
2016 ◽  
Vol 152 ◽  
pp. 318-327 ◽  
Author(s):  
YouSheng Jiang ◽  
ZhiBin Liu ◽  
DongTing Wu ◽  
JianQing Zhang ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Dietary Intake ◽  
South China ◽  
Pearl River Delta ◽  
River Delta ◽  
Pearl River ◽  
Delta Area ◽  
The Pearl River Delta ◽  
The Pearl River ◽  
Retail Food

Long-term observations of tropospheric NO2, SO2 and HCHO by MAX-DOAS in Yangtze River Delta area, China

2018 ◽  
Vol 71 ◽  
pp. 207-221 ◽  
Author(s):  
Xin Tian ◽  
Pinhua Xie ◽  
Jin Xu ◽  
Ang Li ◽  
Yang Wang ◽  
...  
Keyword(s):  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Delta Area ◽  
Tropospheric No2

Evolutionary process of saline groundwater influenced by palaeo-seawater trapped in coastal deltas: A case study in Luanhe River Delta, China

2020 ◽  
Author(s):  
Xianzhang Dang ◽  
Maosheng Gao ◽  
Zhang Wen ◽  
Guohua Hou
Keyword(s):  
Conceptual Model ◽  
Fresh Water ◽  
Late Pleistocene ◽  
Saline Water ◽  
Shallow Groundwater ◽  
Evolutionary Process ◽  
Mineral Weathering ◽  
River Delta ◽  
Shallow Aquifer ◽  
Lagoon Environment

<p>Coastal aquifers provide fresh drinking water to over 20% of the world’s population. In recent times, they have come under immense pressure due to salinization. This study aims to investigate the origin of groundwater salinity and elucidate the major processes controlling shallow groundwater (depth of 0~50m) evolution in the Luanhe River Delta since the Holocene. Rapid increase in Electric Conductivity (EC) profile was observed in the area, as such, based on the vertical distribution of EC and sedimentary history, shallow groundwater was generalized into two zones for analysis: the groundwater in Holocene stratum (HSG) and groundwater in Late Pleistocene stratum (PSG). The isotopic (δ<sup>18</sup>O, δ<sup>2</sup>H and <sup>14</sup>C) analyses showed that the HSG is recharged by modern surface water, while the PSG having enriched isotopic values could have been recharged during a warmer Holocene transgression period. The hydrochemistry analyses demonstrated that seawater is the major source of salinity in groundwater and overtime a series of geochemical processes (mineral weathering and/or cation exchange) modified the chemistry of the groundwater. The combined use of Cl<sup>-</sup><sup> </sup>and δ<sup>18</sup>O yielded four classes of groundwater (fresh water, brackish water, saline water and brine), while the mixing phenomena between fresh water and seawater was identified to be the main evolutionary process of the shallow groundwater. To improve understanding of evolution of multiple groundwater types in a spatial context, a conceptual model was developed integrating the results derived from the presented study in a vertical cross-section. The conceptual model shows that the residual seawater mixes with freshwater from surface recharge at the shallow aquifer of the delta plain where the lagoon environment provides salinity concentration conditions for the formation of hyper-saline water. Due to the precipitation and accumulation of the salinity from hyper-saline water, some brine might form formed in late Pleistocene continental stratum.</p>

Sedimentation at different time scales in Yellow River delta in response to course shift and water-sediment regulation

2020 ◽  
Author(s):  
Qiao Shuqing ◽  
Shi Xuefa ◽  
Yonggui Yu ◽  
Limin Hu ◽  
Lin Zhou ◽  
...  
Keyword(s):  
Sediment Load ◽  
Yellow River ◽  
Yellow River Delta ◽  
River Channel ◽  
River Delta ◽  
The Yellow River ◽  
Hydrodynamic Conditions ◽  
Delta Area ◽  
Fluvial Sediment ◽  
High Sediment

<p>The fluvial sediment to the sea is the base of coastal geomorphology and biogeochemical processes, and its transport is an important pathway to the global biogeochemical cycle. The Yellow River is one of globally well-known large rivers because of high sediment load and Chinese Mother River. Its channel shifts frequently because of high sediment load and steep river-channel gradient in the lower reaches . The terminal channel has shifted more than 50 times since 1855 and the last two changes in 1976 and 1996. Furthermore, Yellow River Conservancy Commission has began to implement Water-Sediment Regulation Scheme (WSRS) since 2002, to increase the main channel discharge capacity and to reduce deposition in the reservoirs and river channel. Surface sediment, multi-core and gravity sediment cores, remote sensing images and bathymetric data near the Yellow River delta were collected to study the impact of WSRS and river terminal change together with the water and sediment discharge at the gauging station. Especially, <sup>7</sup>Be, <sup>210</sup>Pb and <sup>137</sup>Cs, grain size, sediment color and TOC/TN was measured to show sedimentary record of WSRS and channel shift on inter-and intra-annual time scale. The results show that the fresh sediment from Yellow River  during 2014 WSRS period can be transported eastward more than 80 km off the rivermouth, while cannot pass 38° easily. Meanwhile the sediment can penetrate as deep as 12 cm. The subaerial delta area is mostly stable after 2002, and its balance is mainly controlled by the surrounding artificial coastline. The subaqueous delta changed from trapping about 4.6×10<sup>8</sup> t to being eroded ~ 3.1×10<sup>8</sup> t and 1.1×10<sup>8</sup> t each year during the three stages of 1976-1996, 1996-2002 and 2002-2014. It is proposed that the subaerial delta area will change little except for the Q8 outlet area, while the subaqueous delta evolution mostly depend on the Huanghe material besides the hydrodynamic conditions. In addition, the aim of WSRS to scour the lower riverbed will recede in future. This study deepens our understanding of the fluvial sediment disperse pattern and sedimentation under the influence of human activities and hydrodynamic conditions.</p><div>Acknowledgements</div><div> <div>This study was supported by National Programme on Global Change and Air-Sea Interaction (GASI-GEOGE-03) and the Natural Science Foundation of China (U1606401).</div> </div>

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