Numerical study of hydrodynamic and salinity transport processes in the Pink Beach wetlands of the Liao River estuary, China

Abstract

Interaction studies of vegetation within flow environments are essential for the determination of bank protection, morphological characteristics and ecological conditions for wetlands. This paper uses the MIKE 21 hydrodynamic and salinity model to simulate the hydrodynamic characteristics and salinity transport processes in the Pink Beach wetlands of the Liao River estuary. The effect of wetland plants on tidal flow in wetland areas is represented by a varying Manning coefficient in the bottom friction term. Acquisition of the vegetation distribution is based on Landsat TM satellites by remote sensing techniques. Detailed comparisons between field observation and simulated results of water depth, salinity and tidal currents are presented in the vegetated domain of the Pink Beach wetlands. Satisfactory results were obtained from simulations of both flow characteristics and salinity concentration, with or without vegetation. A numerical experiment was conducted based on variations in vegetation density, and compared with the tidal currents in nonvegetated areas; the computed current speed decreased remarkably with an increase in vegetation density. The impact of vegetation on water depth and salinity was simulated, and the findings revealed that wetland vegetation has an insignificant effect on the water depth and salinity in this wetland domain. Several stations (from upstream to downstream) in the Pink Beach wetlands were selected to estimate the longitudinal variation of salinity under different river runoff conditions; the results showed that salinity concentration decreases with an increase in river runoff. This study can consequently help increase the understanding of favourable salinity conditions for particular vegetation growth in the Pink Beach wetlands of the Liao River estuary. The results also provide crucial guidance for related interaction studies of vegetation, flow and salinity in other wetland systems.

Mapping Impact of Tidal Flooding on Solar Salt Farming in Northern Java using a Hydrodynamic Model

“…HDMs originated through resolving Laplace Tidal Equations and using bathymetry data as boundary conditions [48]. The module of MIKE 21 package was used, as one of the most widely used hydrodynamic model in computation by Danish Hydraulic Institute (DHI), including the assessment of hydrographical sequences in non-stratified waters, coastal flooding and storm surge, inland flooding, and overflow [49][50][51]. The MIKE package also represents user-friendly GIS interfaces and provides better possibilities to simulate the flooding using elevation data and bathymetry [52].…”

The impacts of runoff decrease and shoreline change on the salinity distribution in the wetlands of Liao River estuary, China

“…Estuarine salinity has a significant effect on the growth of coastal wetland plants and plays an important role in maintaining the ecological health of estuarine wetlands (Song et al, 2009). Despite this, studies on the spatial and temporal distribution of salinity in estuarine wetlands are limited, with most work generally focusing on salinity transport and saltwater intrusion mechanisms along the estuaries (Ralston et al, 2008;Haralambidou et al, 2010;Veerapaga et al 2019;Wang et al, 2019).…”

“…Due to the recent rapid urban sprawl and growth in population, water consumption has increased dramatically in the Liao River basin. In addition, the upstream closure projects have directly led to a sharp decrease in the downstream runoff of Liao River into Liaodong Bay, which may further affect the exchange and mixing of salt water and freshwater in the estuary (Ralston et al, 2008;Gong and Shen, 2011). Panjin Port is located on the southeast of the LRE, adjacent to the Daliao River (Fig.…”

“…The upstream river network of the LRE is relatively simple, mainly dominated by the Liao River, and is also affected by the river discharge from the Daliao River. The multi-year average river discharge of the Liao River ranges from 101 m 3 s −1 in the dry season to 285 m 3 s −1 in wet season (Qiao et al, 2018), barely reaching 450 m 3 s −1 under extreme precipitation conditions.…”

Assessing Tidal Flood Upon Solar Salt Farming Area in North Part of Java Using Hydrodynamic Model

“…Generally, we exploit hydrodynamic model to evaluate the afterevent flooding in 2016, which has been recorded widely in local media and mentioned by the local farmer during the fieldwork. We utilize DHI MIKE application as one of the most recognizable for hydrodynamic simulation including coastal flooding, storm surge, inland flooding and overflow (Nguyen, 2017;Qiao et al, 2018;Thambas, 2016). The simulation involves MIKE 21 Flexible Mesh (FM) to investigate the water dynamic condition in selected event.…”