Abstract
A tidal lagoon system has multiple environmental, societal, and economic implications. To investigate the mechanism of influence of the geomorphological evolution of a tidal lagoon, the effect of critical erosion shear stress, critical deposition shear stress, sediment settling velocity, and initial bed elevation were assessed by applying the MIKE hydro- and morpho-dynamic model to a typical tidal lagoon, Qilihai Lagoon. According to the simulation results, without sediment supply, an increase of critical erosion, deposition shear stress, or sediment settling velocity gives rise to tidal networks with a stable terrain. Such an equilibrium state can be defined as when the change of net erosion has little variation, which can be achieved due to counter actions between the erosion and deposition effect. Moreover, the influence of the initial bed elevation depends on the lowest tidal level. When the initial bed elevation is below the lowest tidal level, the tidal networks tend to be fully developed. A Spearman correlation analysis indicated that the geomorphological evolution is more sensitive to critical erosion or deposition shear stress than sediment settling velocity and initial bed elevation. Exponential sea level rise contributes to more intensive erosion than the linear or the parabolic sea level rise in the long-term evolution of a tidal lagoon.
Highlights
As a unique landform on the coast, lagoons can be divided into three categories, i.e., tidal lagoons [1], reef lagoons [2,3], and coral atoll lagoons [4]
The objective of this study was to determine the impacts of internal factors on the geomorphological evolution and to provide guidance for the subsequent restoration of tidal lagoons based on the variable importance analysis
The water depth was embedded in the initial bed elevation (IBE) in this study, and unlike the previous study, we revealed that the relationship between the lowest tidal level and the IBE had a dominant effect on the evolution, and that the increase of water level led to more deposition, by either weakening the erosion effect or intensifying the deposition effect
Summary
As a unique landform on the coast, lagoons can be divided into three categories, i.e., tidal lagoons [1], reef lagoons [2,3], and coral atoll lagoons [4]. The number of lagoons is declining at an alarming rate. There were 251 lagoons in China in 1979, but 19 lagoons disappeared in 31 years, due to human activities or changes of natural conditions [5]. Lagoons provides many ecosystem services, such as habitats for fish and shell fish [6]. It is vital to prevent the disappearance of lagoons, due to their ecological and economic benefits [7]. The mechanism of the influence of geomorphological evolution in lagoons has been widely investigated [8,9,10,11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
