The THESEUS consortium is working towards an operational Decision Support System (a DSS) which will allow decision makers to use real data and data models to identify and solve problems regarding coastal defence.

The THESEUS-DSS is a software tool for planning defence strategies against coastal erosion and flooding, which will also address technical, social, economic and environmental aspects. It will be usable as a scoping tool to help coastal managers choose the best combination of mitigation measures for a given site from an available portfolio. As certain crucial aspects (e.g. socio-economic, environmental and mitigation) differ between sites, the underlying data of the THESEUS-DSS needs to be adapted before implementation on new sites. Already, a preliminary version has been developed for the Santander Bay study site, and other versions adapted to other study sites will be developed as well.


The end users - coastal managers and stakeholders – will be able to freely download the software from the THESEUS project website after a registration procedure.


Methodological framework

The underlying model of the THESEUS-DSS follows the Source Pathway Receptor Consequences methodology (or SPRC methodology) and was translated into 7 distinct modules:

SPRC methodology

  1. Sources and drivers module - This module contains a database of predefined functions or values based on climate scenarios and historical data. Data about waves, storms, tides, subsidence and sea level rise due to climate change is included in the database.
  2. Pathway module - This module represents flooding and erosion with and without mitigation measures. The module allows interaction with the end user, allowing him to look at the sensitivity of the outcomes to changes in the erosion forecasts. In other words, does it matter whether 10% or 50% of a feature is eroded? If not, then effort can be more effectively spent on another aspect of the problem that is more critical.
  3. Receptor module - This module contains a database of required information regarding the socio-economic and environmental aspects of the site. Users do not require direct access to the data as long as they choose to follow the predefined scenarios. However, part of this database will be editable.
  4. Consequences module – This module includes both consequences on the environment (damage to habitats, loss of species and breading sites,…) as consequences on economics and society (number of lives lost, health impacts, damaged property and infrastructure, agricultural losses,… ).
  5. Mitigation options module – The mitigation options available in the module will differ between sites. Options to be included should be selected through an open process with input from a number of experts from different backgrounds to make sure that a comprehensive list of options is selected, and not just the options that are common practise in the site.
  6. Risk assessment module - As public risk perceptions can fundamentally compel or constrain the (political, economic and social) ability to address particular risks, risk perception analysis needs to be integrated into vulnerability assessments in order to assess and to reduce negative impacts from flood hazards.
  7. Output module - This module will provide the results of calculations based on selections made in the previous modules. It contains both maps and a matrix showing receptors (rows) versus probabilities of flooding and erosion and ‘ecological and socio-economic consequences (columns).


Graphical User Interface

The end user can access the software tool through the Graphical User Interface (GUI). The GUI is divided into four functional elements which are illustrated in figure 2:

  1. Interaction between the DSS and the Operative System (OS). This element will contain several menus, including HELP on the usage of the GUI and access to relevant documents. It will also allow the end-user to launch and save different processes under different climate, socio-economic scenarios or to provide comparisons between different exploratory analysis cases.
  2. Selection element of Predefined Scenarios or User Defined Scenarios for the different systems (Climatic, Socio-economic and Environmental).
  3. Results display and interaction element.
  4. The work flow element which can be accessed through 5 tabs: “processed data”, “exploratory analysis”, “mitigation options”, “impact/consequences” and “risk analysis”.


preliminary test version of the Graphical User Interface small
Figure 2: The preliminary test version of the Graphical User Interface (GUI) adapted for the Santander Bay study site. The 4 functional elements are indicated with red rectangles.


Schematic presentation of the workflow options
Figure 3: Schematic presentation of the work flow options.


Using the GUI, the work flow is likely to consist of 4 steps as is schematically presented in figure 3. These steps are:

  1. The end user first has to define whether he wants to use the predefined climatic, socio-economical and environmental scenarios or whether he wants adjust any of them. The “exploratory analysis” tab will then visualize the chosen scenario on the map.
  2. The predicted consequences of the selected scenarios can be assessed on the map.
  3. The socio-economic and environmental consequences are integrated into a risk assessment, that can be analysed on the map (e.g. figure 4).
  4. The end user can then make a selection from the predefined mitigation options, and visualize the predicted consequences and risk assessments with the mitigation options in place. This will allow the coastal manager to select the most efficient mitigation options.


The visualisation of the risk assessment
Figure 4: The visualisation of the risk assessment according to the selected scenarios in the preliminary test version of the Graphical User Interface (GUI) adapted for the Santander Bay study site.