About COAST (Built on the Global Mapper SDK)

To enable this extension, see Extensions.

COAST DAMAGE ASSESSMENT TOOL

The COAST (COastal Adaptation to Sea level rise Tool) is a process that helps users answer questions in regards to the costs and benefits of actions and strategies to avoid damages to assets from sea level rise and/or coastal flooding. For the past five years, Blue Marble Geographics has partnered with the New England Environmental Finance Center (NEEFC) from the Edmund Muskie School of Policy Research at the University of Southern Maine to develop the software interface for COAST. The COAST software tool, a free download, is built on the Global Mapper software developer toolkit and promoted in partnership with Catalysis Adaptation Partners.

As more cities and regions are hit hard by storms, public pressure for better infrastructure planning is growing. A consensus is emerging that in many cases, 'putting it back the way it was' is not the right answer. Community leaders may be ready to take new actions to adapt to changing conditions, but may also be unsure whether such new ideas are good investments. They may well ask: 'How much should we pay to lower risks, and where is the line between a wise choice and a foolish one?' Coastal Adaptation to Sea Level Rise (COAST) is a tool that helps communities answer these questions. It predicts damages from varying numbers of storms of different intensities, and evaluates relative benefits and costs of response strategies that stakeholders select.

The COAST process uses two types of information to help communities evaluate their options when planning their response to these changing conditions.  The first is a map that contains a graphical representation of the damages caused by a specific storm scenario.  This map is useful to help people visualize the areas that will be flooded, and the monetary effects of that flooding.  Each group of stakeholders can use different criteria to define "damages" in the context of their local population.  For example, they might want to look at lost tax revenue or the costs for businesses that may have to close or relocate.  The second type of output is a chart of expected cumulative damages over time from repeated storms and rising sea level.  The chart can be customized to include multiple different scenarios for sea-level rise (including no sea-level rise) and the effects of mitigating actions taken by the community in future years.

An example of COAST graphic output is below, showing a no-adaptation-action scenario for 1.8 meters of sea level rise and a 100-year flood event in the year 2100, for a portion of downtown Portland, Maine. The z-axis polygons represent cumulative expected lost real estate and building contents value of over $500 million (maximum loss per parcel is over $54.1 million). Adaptation actions subsequently modeled in this location included installing a surge barrier and a levee, each of which could provide some protection to the vulnerable areas.

Visually, each adaptation action is then represented in maps showing reduced or eliminated polygons extruding out of the landscape. Numerically, this is an effective way of showing up front and maintenance costs of hard-structure approaches versus expected damages from particular inundation events. Soft-structure approaches may also be modeled, such as flood-proofing, rezoning over time, and others.

Importantly, the approach allows modeling of ranges of SLR and storm surge frequency and intensity. Combining multiple future scenarios provides stakeholders an opportunity to select their expectation of future conditions and then visualize damages under action versus no-action scenarios. COAST output is in the form of files compatible with Google Earth, and tables showing cumulative expected damages for the selected vulnerable asset under the adaptation scenarios stakeholders have developed, that allow cost-benefit analysis of candidate adaptation actions.

The COAST Damage Assessment tool is a stand-alone software product that can be used to produce the maps and cost estimates used in the COAST process.  It is easy to use, but the COAST process requires that a certain amount of data preparation specific to the local environment be completed before it can be used effectively. 

NOTE FOR TRANSPORTATION ASSESSMENTS:

If you are aiming to conduct benefit-cost analysis for candidate engineering designs on alternative transportation structures, please note the following. Once you have completed work with the DST portion of COAST to prioritize which roads or bridges to work with, or if you already know which road or bridge is the highest priority, you are ready to begin using COAST for benefit-cost work with that structure. It is important to note that the process described here is essentially the same for 10,000 real estate parcels as it is for a single road or bridge (A depth-damage function is customized for the asset and surge and SLR scenarios are run over time, under specified probabilities. Damages to that asset under a no-action scenario are then compared with design/build costs vs. avoided costs over time). That is, transportation users can use the Portland tutorial data sets and know that exactly the same process will be used, just for the single uploaded transportation asset vs. the large suite of real estate parcels as the vulnerable asset.