Impacts of future sea level rise on salt water intrusion in the Changjiang River Estuary

Abstract. Future sea level rise as a consequence of global warming will affect the world's coastal regions. Even though the pace of sea level rise is not clear, the consequences will be severe and global. Commonly the effects of future sea level rise are investigated for relatively vulnerable development countries; however, a whole range of varying regions need to be considered in order to improve the understanding of global consequences. In this paper we investigate consequences of future sea level rise along the coast of the Baltic Sea island of Gotland, Sweden, with the aim to fill knowledge gaps regarding comparatively well-suited areas in non-development countries. We study both the quantity of loss of infrastructure, cultural and natural values for the case of a two metre sea level rise of the Baltic Sea, and the effects of climate change on seawater intrusion in coastal aquifers, causing the indirect effect of salt water intrusion in wells. We conduct a multi-criteria risk analysis by using Lidar data on land elevation and GIS-vulnerability mapping, which gives formerly unimaginable precision in the application of distance and elevation parameters. We find that in case of a 2 m sea level rise, 3 % of the land area of Gotland, corresponding to 99 km2, will be inundated. The features most strongly affected are items of touristic or nature values, including camping places, shore meadows, sea stack areas, and endangered plants and species habitats. In total, 231 out of 7354 wells will be directly inundated, and the number of wells in the high-risk zone for saltwater intrusion in wells will increase considerably. Some values will be irreversibly lost due to e.g. inundation of sea stacks and the passing of tipping points for sea water intrusion into coastal aquifers; others might simply be moved further inland, but this requires considerable economic means and prioritization. With nature tourism being one of the main income sources of Gotland, monitoring and planning is required to meet the changes. Seeing Gotland in a global perspective, this island shows that holistic multi-feature studies of future consequences of sea level rise are required, to identify overall consequences for individual regions.

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Simulation to Investigate the Reasons for the Sediment Deposition in the Upper Reach of the Deepwater Navigation Channel in the Changjiang River Estuary

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.610-613.1237 ◽

2012 ◽

Vol 610-613 ◽

pp. 1237-1241

Author(s):

Jie Gu ◽

Wei Chen ◽

Xin Qin ◽

Dan Qing Ma ◽

Xiao Li Wang ◽

...

Keyword(s):

River Estuary ◽

Sediment Deposition ◽

Changjiang River ◽

Changjiang River Estuary ◽

The Changjiang River ◽

The North ◽

Velocity Magnitude ◽

Navigation Channel ◽

The Changjiang River Estuary ◽

Set Up

At present, the upper reach of the Deepwater Navigation Channel is silted heavily, which brings negative influences on navigation. A two-dimensional numerical model is set up to simulate the hydrodynamics of the Changjiang River Estuary with Delft3D-FLOW in this paper. This model has been validated with the observed tidal level, flow velocity magnitude and direction, and the computed results agree well with the observed data, which also shows the model can well simulate the hydrodynamics of the Changjiang River Estuary caused by the Deepwater Navigation Channel Project. Based on the analysis of computed results, especially the velocity along the South Passage and North Passage, the flood and ebb flow in the Hengsha Passage, and the flow spilt ratio of South Passage and North Passage, it presents that one fundamental reason for the sediment deposition in the upper reach of the Deepwater Navigation Channel is that the velocity along the North Passage is far less than that along South Passage, above all, the velocity in North Passage upstream of the Hengsha Passage is even smaller; another reason is that the flood and ebb flow of Hengsha Passage are large, which weakens the water exchange between the North Passage and South Channel.

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Assessment of Extreme Storm Surges over the Changjiang River Estuary from a Wave–Current Coupled Model

Journal of Marine Science and Engineering ◽

10.3390/jmse9111222 ◽

2021 ◽

Vol 9 (11) ◽

pp. 1222

Author(s):

Yutao Chi ◽

Zengrui Rong

Keyword(s):

Return Period ◽

River Estuary ◽

Coupled Model ◽

Storm Surges ◽

Distribution Model ◽

Changjiang River ◽

Changjiang River Estuary ◽

The Changjiang River ◽

The Changjiang River Estuary ◽

The Impact

Disastrous storm surges and waves caused by typhoons are major marine dynamic disasters affecting the east China coast and the Changjiang River Estuary, especially when they occur coincidentally. In this study, a high-resolution wave–current coupled model consisting of ADCIRC (Advanced Circulation) and SWAN (Simulating Waves Nearshore) was established and validated. The model shows reasonable skills in reproducing the surge levels and waves. The storm surges and associated waves are then simulated for 98 typhoons affecting the Changjiang River Estuary over the past 32 years (1987–2018). Two different wind fields, the ERA reanalysis and the ERA-based synthetic wind with a theoretical typhoon model, were adopted to discern the potential uncertainties associated with winds. Model results forced by the ERA reanalysis show comparative skills with the synthetic winds, but differences may be relatively large in specific stations. The extreme surge levels with a 50-year return period are then presented based on the coupled model results and the Gumbel distribution model. Higher risk is presented in Hangzhou Bay and the nearshore region along the coast of Zhejiang. Comparative runs with and without wave effects were conducted to discern the impact of waves on the extreme surge levels. The wave setup contributes to 2–12.5% of the 50-year extreme surge level. Furthermore, the joint exceedance probabilities of high surge levels and high wave height were evaluated with the Gumbel–logistic statistic model. Given the same joint return period, the nearshore region along the coast of Zhejiang is more vulnerable with high surges and large waves than the Changjiang River Estuary with large waves and moderate surges.

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Review of Jian et al. BG. Effets of the interaction of ocean acidification, solar radiation, and warming on biogenic dimethylated sulphur compounds cycling in the Changjiang River Estuary

10.5194/bg-2017-453-rc1 ◽

2017 ◽

Author(s):

Anonymous

Keyword(s):

Solar Radiation ◽

Ocean Acidification ◽

River Estuary ◽

Changjiang River ◽

Changjiang River Estuary ◽

Sulphur Compounds ◽

The Changjiang River ◽

The Changjiang River Estuary

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Effects of the interaction of ocean acidification, solar radiation, and warming on biogenic dimethylated sulfur compounds cycling in the Changjiang River Estuary

10.5194/bg-2017-453 ◽

2017 ◽

Author(s):

Shan Jian ◽

Jing Zhang ◽

Hong-Hai Zhang ◽

Gui-Peng Yang

Keyword(s):

Solar Radiation ◽

Ocean Acidification ◽

River Estuary ◽

Sulfur Compounds ◽

Changjiang River ◽

Changjiang River Estuary ◽

Chl A ◽

The Changjiang River ◽

Temperature Conditions ◽

The Changjiang River Estuary

Abstract. Ocean acidification (OA) affects marine primary productivity and community structure, and therefore may influence the biogeochemical cycles of volatile biogenic dimethyl sulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) and photochemical oxidation product dimethyl sulfoxide (DMSO). A 23-day incubation experiment on board was conducted to investigate the short-term response of biogenic sulfur compounds production and cycling to OA in the Changjiang River Estuary and further understand its effects on biogenic sulfur compounds. Result showed that phytoplankton abundance and species presented remarkable differences under three different pH levels in the late stage of the experiment. A significant reduction in chlorophyll a (Chl-a), DMS, particulate DMSP (DMSPp), and dissolved DMSO (DMSOd) concentrations was identified under high CO2 levels. Moreover, minimal change was observed in the production of dissolved DMSP (DMSPd) and particulate DMSO (DMSOp) among treatments. The ratios of DMS, total DMSP (DMSPt), and total DMSO (DMSOt) to Chl-a were also not affected by a change in pH. In addition, DMS and DMSOd were highly related to mean bacterial abundance under three pH levels. Additional incubation experiments on light and temperature showed that the influence of pH on productions of dimethylated sulfur compounds also depended on solar radiation and temperature conditions. DMS photodegradation rate increased with decreasing pH under full-spectrum natural light and UVB light. Thus, OA may lead to decreasing DMS concentrations in the surface seawater. Light and temperature conditions also play an important role in the production and cycling of biogenic sulfur compounds.

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