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Coastline intervention tool - Holland Coast (ITHC)
The Interactive Design Tool for the Holland Coast (ITHC) is a Interactive group modelling (MapTable) application aiming at assisting decision makers, project developers and stakeholders in the early development stages of coastal maintenance strategies for the Holland Coast. The Holland Coast, i.e. the coast of the provinces South-Holland and North-Holland, the Netherlands, is a sandy dune coast characterized by a wide variety of economical, ecological and recreational functions, hence a large and diverse group of (potential) stakeholders. For the successful implementation of coastal maintenance strategies, the support of these stakeholders is of vital importance. With the Interactive Design Tool users can easily and rapidly evaluate the consequences of various coastal interventions (e.g. nourishments, coastal structures) for indicators such as coastline development, dune development and habitat suitability. The tool has the ability to evaluate (mutual) interactions between new interventions and existing coastal structures in both space (small- vs. large-scale) and time (short- vs. long-term). This enables users to get insight into the consequences of their choices, to determine their position, and to provide input into the design process.
Building with Nature interest
The ITHC is a platform for interaction of knowledge from different disciplines (coastal engineering, marine & dune ecology, ecosystem services, cost-benefit analysis) and people with different roles in the development process (policy makers, stakeholders, professionals). It can be used to gain insight into the effects of human interventions and changes in environmental conditions (such as sea level rise), as well as their interactions with user functions. In this way it facilitates interaction between eco-dynamic project developers and stakeholders, which is one of the three main eco-dynamic development & design principles of Building with Nature.
In principle the Interactive Design Tool can be applied in all .In the current (2012) version, however, the limitations of the underlying model practically restrict its use to the initiation and planning & design phases, e.g. to identify and evaluate first alternative visions/designs. For more detailed design stages more detailed models could be plugged in. The Interactive Design Tool for the Holland Coast is just one example of an interactive
Although the tool now focuses on the Holland Coast, the underlying framework, consisting of an interface, pre- and post-processing software and a model, can be applied to coastal systems anywhere in the world. Any type of model can be plugged in, as long as the proper software for pre- and post-processing is available or developed. Note, however, that the current empirical relations to link coastline development to dune development, ecology and other indicators are specific for the Holland Coast and may not be applicable to other coastal systems.
How to Use
The focus of this section is on the "technical" use of the Interactive Design Tool. For more information on the setting in which these types of tools can best be used we refer to the Interactive group modelling (MapTable) tool description.
Starting point of the Interactive Design Tool is that it is easy to use, also by non-experts. Therefore, the user interface strives to facilitate intuitive use, by limiting the number of buttons, keeping the number of required user actions to a minimum and checking for erroneous input. Results are visualized in a Google Earth window, which most users are acquainted with. In its present (2012) form the tool gives a first estimate of the impact of coastal interventions. Results should be interpreted qualitatively rather than quantitatively. Although starting a simulation is relatively fast and easy, workshops in cooperation with Atelier Kustkwaliteit made clear that proper interpretation of the results requires knowledge of coastal processes, underlying model assumptions and the relations linking indicators to coastline development. Therefore, when using the tool in practice (in stakeholder workshops), it is strongly recommended to appoint a moderator with such background knowledge. This moderator can put the results into perspective and explain the possibilities and limitations of the tool.
The Interactive Design Tool for the Holland Coast is available in two versions:
Setting up a scenario for the Interactive Design Tool involves the following steps:
Tool window Interactive Design Tool for the Holland Coast
2. The Tool panel consists of two menus, i.e. 'Scenario Input' and 'Change Map'. In the 'Scenario Input' menu, the user can select whether sea-level rise needs to be taken into account and which indicators should be processed. In the 'Change Maps' menu, the background map can be chosen, as is shown in the following screenshot:
Switching background from hybrid to street map
3. The user can add measures (nourishments, groynes or revetments) by selecting them from the toolbar and clicking the location where the measure should be implemented. Automatically, a window pops up in which the user can fill out specifications for the selected measure (see screenshot for adding a nourishment). Measures can be moved by selecting the button 'Relocate', selecting the object to be relocated and dragging it to its new position. With the 'Modify' button, the user can adjust the specification of the measures.
Adding a nourishment to a scenario
4. In the 'Scenario' menu, the user can start a new scenario (all existing measures are deleted and a default empty scenario is loaded), load a previously saved scenario, or save the scenario he/she has been working on (see screenshot).
5. Once the user is satisfied with the scenario, he/she can select 'Run scenario entirely' from the 'Run' menu. This will trigger a window (see screenshot) in which the name and duration of the scenario can be selected. Upon pressing 'OK' the simulation will start.
Run a scenario
6. The results will be shown in the Google Earth Panel of the OpenEarth Viewer (see screenshot). The yellow triangle indicates the location of the nourishment, the yellow line the coastline position, and the red and green bars an exaggeration of erosion and deposition along the coast relative to the initial coastline. The icons indicate the states of the indicators. In this example, dunes (dune class, habitat richness, dynamics) and ecology (three types of benthos and nursery area for fish). Red icons indicate a worsening state, green colors an improving state and yellow/grey colors approximately equal state relative to the initial state.
Scenario output (coastline development, ecology and dunes)
The Interactive Design Tool for the Holland Coast consists of the following modules:
Potential future improvements on the ecological module
To improve the reliability of the IDTHC model outcomes, additions to the benthos and fish nursery modules would involve:
The dune module could be improved by:
To better inform stakeholders, a separate module on nourishment costs is being implemented in the ITHC (not covered in this report).
The tool is a trade-off between model accuracy and calculation time. It is based on a relatively simple but fast coastline model. Some physical processes, such as cross-shore sediment transport, are not included and the long-shore cell size is relatively large (about 250 m), whence model results need to be interpreted with care. Users (i.e. stakeholders) need to be made aware of these limitations. This model should not be used without moderation by an expert, who can clarify the results if necessary and explain model limitations. The tool is most suited in the beginning of the design process, when all possible scenarios are being explored. In later project phases (such as the final design and construction phases) a higher model accuracy may be needed.
The Interactive Design Tool for the Holland Coast has already been used in workshops, where various stakeholders made plans for the future of the Dutch coast. It is an effective tool to visualise the impact of management measures (nourishments and revetments) in both time and space. This is of great value because individual processes act as different temporal and spatial scales, and respond differently to the measures.
- Atelier Kustkwaliteit (AKK)
- Ecologically Smart Nourishments
- Other applications
Access to the Interactive Tool Coastal Intervention - Holland Coast