Many of the world’s coastlines are vulnerable to erosion and at risk from tidal flooding.Addressing and managing these risks presents major challenges especially when seeking to sustainably balance the requirements f...Many of the world’s coastlines are vulnerable to erosion and at risk from tidal flooding.Addressing and managing these risks presents major challenges especially when seeking to sustainably balance the requirements for coastal protection with other economic,environmental,and societal objectives.The nature and scale of these challenges varies greatly from site to site and can often be magnified on dynamic shorelines that are subject to a high degree of physical and ecological change.Applying an ongoing process of adaptive management is widely agreed to be a key mechanism for dealing with such dynamic conditions and issues of uncertainty.However,under this process it can be difficult for different stakeholders to reach a consensus about the most suitable intervention actions.In part,this can arise because there is an incomplete understanding about past,present,and,especially,future environmental processes.It can also occur due to differences in the perceptions and priorities of the relevant stakeholders.This paper reviews some of these complexities using,as a case study,recent developments of a shingle spit and tidal inlet at Pagham Harbour,on the south coast of the UK.This example provides lessons in the application of adaptive management and working with nature concepts in a particularly complex coastal setting.This paper considers these lessons in the context of the site’s history,the legal and policy framework,and established understanding about the natural environment.展开更多
Future sediment transport from the North Sea coasts to the Dutch Wadden Sea for various future sea level scenarios has been studied because it influences the future sand nourishment demand for the maintenance of the c...Future sediment transport from the North Sea coasts to the Dutch Wadden Sea for various future sea level scenarios has been studied because it influences the future sand nourishment demand for the maintenance of the coastline and because it determines bio-geomorphological development of the Wadden Sea.The present study focuses on two questions which have not yet been considered in the previous modelling studies using ASMITA:How will the transport develop around drowning of the intertidal flats in the Wadden Sea?How will tidal range change influ-ence the future sediment exchange?By using SLR scenarios with faster acceleration and running the simulations for longer periods of time some inlets exhibited drowning,i.e.,where the tidal flat volume vanishes.When drowning occurs,the sediment import rate approaches a maximum or a minimum,depending on the initial morphological state of the tidal inlet system.This maximum or minimum rate for a certain tidal inlet system depends on the SLR scenario.Theoretical analysis as well as modelling results show that tidal range change will influence the sediment import to the Wadden Sea.A tidal range increase will cause a decrease of the sediment demand in the Wadden Sea resulting into less sediment import to the Wadden Sea.It is thus important to study the tidal range development in the Wadden Sea by considering the interaction between SLR,tidal range change and morphological development in the system.It is further concluded that the empirical relation used in the previous studies is not representative of conditions in a tidal basin with fixed basin area,even though this relation has been derived from field observations in many tidal inlet systems worldwide.The equilibrium channel volume should be proportional to the tidal prism instead of to its 1.5^(th) power.展开更多
文摘Many of the world’s coastlines are vulnerable to erosion and at risk from tidal flooding.Addressing and managing these risks presents major challenges especially when seeking to sustainably balance the requirements for coastal protection with other economic,environmental,and societal objectives.The nature and scale of these challenges varies greatly from site to site and can often be magnified on dynamic shorelines that are subject to a high degree of physical and ecological change.Applying an ongoing process of adaptive management is widely agreed to be a key mechanism for dealing with such dynamic conditions and issues of uncertainty.However,under this process it can be difficult for different stakeholders to reach a consensus about the most suitable intervention actions.In part,this can arise because there is an incomplete understanding about past,present,and,especially,future environmental processes.It can also occur due to differences in the perceptions and priorities of the relevant stakeholders.This paper reviews some of these complexities using,as a case study,recent developments of a shingle spit and tidal inlet at Pagham Harbour,on the south coast of the UK.This example provides lessons in the application of adaptive management and working with nature concepts in a particularly complex coastal setting.This paper considers these lessons in the context of the site’s history,the legal and policy framework,and established understanding about the natural environment.
基金supported by the Dutch national research programme Sea level rise,theme Sandy coastsby the Dutch Ministry of Economic Affars and Climate via Programme subsidy Deltares.
文摘Future sediment transport from the North Sea coasts to the Dutch Wadden Sea for various future sea level scenarios has been studied because it influences the future sand nourishment demand for the maintenance of the coastline and because it determines bio-geomorphological development of the Wadden Sea.The present study focuses on two questions which have not yet been considered in the previous modelling studies using ASMITA:How will the transport develop around drowning of the intertidal flats in the Wadden Sea?How will tidal range change influ-ence the future sediment exchange?By using SLR scenarios with faster acceleration and running the simulations for longer periods of time some inlets exhibited drowning,i.e.,where the tidal flat volume vanishes.When drowning occurs,the sediment import rate approaches a maximum or a minimum,depending on the initial morphological state of the tidal inlet system.This maximum or minimum rate for a certain tidal inlet system depends on the SLR scenario.Theoretical analysis as well as modelling results show that tidal range change will influence the sediment import to the Wadden Sea.A tidal range increase will cause a decrease of the sediment demand in the Wadden Sea resulting into less sediment import to the Wadden Sea.It is thus important to study the tidal range development in the Wadden Sea by considering the interaction between SLR,tidal range change and morphological development in the system.It is further concluded that the empirical relation used in the previous studies is not representative of conditions in a tidal basin with fixed basin area,even though this relation has been derived from field observations in many tidal inlet systems worldwide.The equilibrium channel volume should be proportional to the tidal prism instead of to its 1.5^(th) power.
