Welcome to the Endure mapping tool
ENDURE aims to improve coastal adaptation to climate change, focusing on 110km of sand dunes with 6 partners from The Netherlands, Belgium, France and the UK. The project is receiving funding through the Interreg 2 Seas programme and will last three years, finishing in December 2020. The project aims to improve the capacity of 2 Seas stakeholders to apply ecosystem-based management approaches, reducing reliance on hard engineering solutions. We will draw from cross border expertise to inform and supply new purpose-developed solutions to answer real world dune management problems occurring now under climate change. Our Partnership has been carefully constructed to include national, regional and local partners to really drive change into clear, practical improvements in dune management across the 2 Seas area. We will collaborate to capitalise on the best knowledge and expertise available across the Member States. We will work to improve and restore the ability of dunes to act as adaptive, living sea defences for a coastline which is more naturally resilient to erosion, flooding and sea level rise.
Further information about the wider project and partners can be found on the project website here:http://www.endure.eu.com
This tool is designed to help dune managers implement solutions on their sites. It is not expected that it will enable these groups to make precise dune management decisions at specific sites, instead it is a communication tool designed to get people thinking about dune management in a new way. It will support stakeholders in learning about ecosystem-based solutions and new technology, helping to grow understanding of the impacts of a range of dune management techniques. Greater knowledge and understanding of dune management options will in turn help to influence the decision-making process and generate lasting impact. The final stage of development for this mapping tool, will be the addition of a marram health tool, to help visualise the health of a dune based on marram grass coverage and health of the plants (based on samples by our university partner). This will enable users to instantly see which areas are in good health or not. Of course, this does not show the flood resistance of the dunes but their biological and morphological health.
For the purposes of this project, hard engineering is defined as traditional methods of coastal intervention working to keep dunes and shorelines in a fixed position e.g. groynes, sea walls, sea dykes etc. Ecosystem-based solutions imply a degree of freedom for the coast e.g. space for dunes to migrate and a constant source of sediment to feed this migration. They are defined as solutions which work with nature and coastal processes rather than against them e.g. sand nourishment (both on beach and shore face), dynamic dune systems with blow outs, vegetation/reed screens to trap sand.NOTE! The viewer and its functions perform best using Google Chrome browser.
This tabpage is about the science behind this webinterface and especially the results of the tab Function as expressed on top of this information panel
The science behind Sea Level Rise Effects is based on the NATURE publication The State of the World's Beaches
Some additional background information about the terminology used:
- Return Period
The chosen option 'Return period' means the extreme event with a magnitude that has the chosen number of years as return period. It does not mean that a 100-year return period means that it is an event that only happens every 100 years. In any 100 year period it can happen once, twice or more or not at all. However, the return period gives an impression of the likelihood and magnitude of a certain event.
- Storm-Impact Scale Regimes
To assess the impact of sea level rise on coastal systems, there is looked at the storm impact scales (as proposed by the paper Sallanger 2000 ,’Storm Impact Scale for Barrier Islands’). For dune systems, 4 different types of regimes are distinguished describing the state of the system (swash/collision/overwash/inundation). In the function it is assessed what the regime of the present situation is and how this might change with 1 or 2 meters of sea level rise. This gives insight in how well the dune system might adapt to sea level rise.
To determine the storm impact regimes of Sallanger (as shown in result screen after application of the function Sea Level Rise Effects), multiple steps have been performed. These calculations are done using the values presented in tab Parameters.
At first it is calculated how much wave run-up there is for the selected return period extreme event, using the relations given by Stockdon et al. 2007. The wave length is: L0 = (g * Tp ^ 2) / (2 * pi). Therefore the runup that is exceed by 2% of the waves is then: R2% = 1.1 * (0.35 * Beach_slope * (Hs * L0) ^ 0.5 + ((Hs * L0 * (0.563 * Beach_slope * 2 + 0.004)) ^ 0.5) / 2). Hereby Beach_slope is the beach slope between the dune foot and the location of the Mean High Water (MHW) value. Hs is the offshore significant wave height from the table and Tp the Offshore peak wave period. Based on this, the supplied storm surge level and the chosen sea level rise value, the maximum runup is calculation by summing up these values. This gives the value Rhigh. Additionally the Rlow is calculated by summing storm surge level with the wave setup. For the wave setup the formula is the following: setup = 0.35 * Beach_slope * (Hs * L0) ^ 0.5. Based on these values Rhigh and Rlow it is determined in what regime the current state and chosen scenario is (see figure).
In case the regime is in the collision regime, some additional calculations are done. Using the Bruun rule there can be estimated how far the coast would retreat based on a certain sea level rise in case the dune system could fully adapt. To calculate this at first the Depth of Closure (DoC) is needed, this is the depth where it is assumed that deeper than this no significant sediment transport takes place. The formula of Hallermeijer(1981) supplies this based on the wave conditions that are only exceeded 12 hours per year (Hs,year & Tp,year): DoC = 2.28 * Hs,year - 68.5 * (Hs,year ^2 ) / (g * (Tp,year)^2). Now the distance L between the top of the dune (dune_top ) and the DoC is calculated from the transect, which is used for the Bruun rule: Bruun = SLR * L / (DoC + dune_top). This gives the retreat of the dune in meters for the given sea level rise (SLR). It can happen that the prediction is that a profile will stay in the same collision regime, but still maybe will not adapt sufficiently to sea level rise. This can happen when the dune is insufficiently wide compared to the retreat of the dune. Then the dune must retreat landwards through natural processes or sediment management.
The Swash regime describes a storm where wave runup is confined below the dune foot. During a storm the foreshore typically erodes and recovers afterwards.
The Collision regime during is describing a storm where the wave runup exceeds the dune foot, but is below the top of the dune. The front of the dune is impacted by the storm.
The Overwash regime describes a storm where wave runup overtops the top of the dune. Because of this sediment is transported landwards, the overtopping waves may lead to flooding issues in the hinterland.
The Inundation regime describes a storm where the storm surge is sufficient to completely and continuously submerge the dune system. A lot of sediment is transported landward and there if significant flooding of the hinterland.
source: All showed figures of the mentioned regimes are courtesy of Goslin, Jérôme & Clemmensen, Lars. (2017). Proxy records of Holocene storm events in coastal barrier systems: Storm-wave induced markers. Quaternary Science Reviews. 174. 80-119. 10.1016/j.quascirev.2017.08.026.