Resilient Coastal Cities Explorer

What is the Resilient Coastal Cities project?

In October 2015 the Global Disaster Preparedness Center (GDPC) of the American Red Cross started a 5-year project supported by the U.S. Agency for International Development’s Office of U.S. Foreign Disaster Assistance (USAID/OFDA) to prototype approaches for coalition-building, addressing increasing risk in a set of coastal cities in Southeast Asia and the Pacific. The goal of the Resilient Coastal Citiesproject is to enhance local collaboration and problem solving to support effective climate change adaptation. The Nature Conservancy (TNC) has joined efforts with GDPC in the project to help identify ways that nature can be a part of building social-ecological community resilience before, during, and after natural disasters.

What is the Resilient Coastal Cities Explorer?

The Resilient Coastal Cities Exploreris an online mapping decision support tool, or web-responsive mobile app, that demonstrates the critical role mangroves play in reducing social and economic vulnerability to flooding in Semarang, Indonesia.The app helpscity planners and disaster managers better understand how nature-based adaptation solutions can reduce the risk of flooding in the city.

Who developed it?

TNC developed the spatial analysis and web app in collaboration with FloodTags, Wetlands International and Esri for Pelang Merah Indonesia (Red Cross Indonesia) and the Global Disaster Preparedness Center of the American Red Cross.

Who should use it?

Central Java city planners, disaster managers, and decision makers who need to assess real-time flood risk information alongside socio-economic and ecological data to help identify viable adaptation solutions that build resilience and reduce the risk of city flooding and inundation.

How does it work?

There are three main components of the tool:

Real-time Flood Reports
FloodTagsdeveloped software to analyze Twitter content to derive real-time information on potential flood events. FloodTags worked with the TNC Indonesia team to train their algorithms to search tweets written in Bahasa for key words that help identify the location of flood events. For each event, the most probable location, quantification of uncertainty, number of tweets per class, and frequently used keywords were summarized. FloodTags filtered and validated each flood report using a mix of natural language processing, relevant rainfall data, and remote sensing. The final data product is distributed through the FloodTags dashboard which TNC accesses to map flood-prone areas and summarize impacts to people and property.

Administrative Summaries

Flood Risk
The Resilient Coastal Cities Explorerhelps identify where people, places, and livelihoods are at risk from flooding within an administrative unit (kecamatan). Key parameters were selected based on availability and scale of the data, summarized within each kecamatan, and related to real time flood reports gleaned from FloodTags. The interactive map shows summary statistics of people and assets potentially impacted within kecamatans. The user can view either a single flood event or select a date range to view cumulative flood tweets to highlight the most vulnerable areas. The user can also click on a single kecamatan to view specific statistics by unit. The allows a planner or disaster manager to quickly assess flood impacts in order to help prioritize response and adaptation actions.

Adaptation Solutions
The Resilient Coastal Cities Exploreralso helps planners and land managers visualize opportunities for nature-based adaptation solutions that can help reduce flood risk. Adaptation solutions were selected based on actions that are feasible in the region, namely mangrove restoration and open space reclamation/preservation. Key metrics (i.e., low production rice fields) were summarized by kecamatan and displayed based on solution type. The ability to view potential adaptation and flood mitigation opportunities alongside flood risk enables planners to consider multiple adaptation solutions that will help make their communities more resilient to future flooding while also providing benefits back to the community.
Table of Administrative Unit analysis

Theme	Metric per Admin Unit	Rationale
RISK: Potential Flood Impacts on People	Number of tweets related to flooding	real-time social media data on observed flooding helps to ID chronic flooding areas to help prioritize response and recovery actions
RISK: Potential Flood Impacts on People	Number of people potentially affected	the more people affected, the more potential socio-economic impacts felt across the region
RISK: Potential Flood Impacts on Places	Number of Educational buildings potentially affected	schools and research facilities often provide shelter options during natural hazards. Interruption in educational activities could also have an economic impact if parents are forced to stay home with children.
RISK: Potential Flood Impacts on Places	Number of buildings of worship potentially affected	places of worship provide shelter and community support during and after natural disasters.
RISK: Potential Flood Impacts on Places	Number of Hospitals potentially affected	could impact care and response time to emergencies
RISK: Potential Flood Impacts on Livelihoods	Length of roads potentially affected (km)	flooding of major roads can shut down key routes to economic centers and prevent people from getting to work, negatively impacting their livelihoods and the businesses
RISK: Potential Flood Impacts on Livelihoods	Area of ag land potentially affected (ha)	damage to ag land impacts farmers and consumers
RISK: Potential Flood Impacts on Livelihoods	Number of tourism and culturally important sites potentially affected	these areas provide rec/tourism benefits to the economy
RISK: Potential Flood Impacts on Livelihoods	Area of rice fields potentially affected (ha)	damage to ag land impacts farmers and consumers
ADAPTATION SOLUTION	Number of low production rice fields	Areas that have been deemed “low productivity” by the Ministry of Geospatial Agriculture (Kementrian Pertanian Geospasial) may be areas to prioritize for mangroves/wetland restoration if rice is no longer economically viable.
ADAPTATION SOLUTION	Area of convertible rice fields (ha)	Areas deemed as “ Rice Fields that can be converted” by the Ministry of Geospatial Agriculture (Kementrian Pertanian Geospasial) may be areas to prioritize for mangroves/wetland restoration if rice is no longer economically viable.
ADAPTATION SOLUTION	Area of potentially restorable mangroves (ha)	historical mangrove areas that have been identified as potentially restorable in prior analyses.

Mangrove Restoration Simulations
Based on a model built in collaboration with Esri, a video played from within the app enables stakeholders to visualize the simulated benefits of a landscape-scale mangrove restoration scenarios in 3-dimensional space. The simulation is based on a “permeable dam” mangrove restoration approach which has been implemented by Wetlands Internationalelsewhere in the region. This passive restoration style uses stick structures in the water to mimic the sediment deposition and erosion control services provided by fully grown mangroves. Once erosion has stopped and the shoreline has accreted (2-5 years), mangroves are expected to colonize naturally over time (3-5 years) and stabilize the shoreline without manual planting or regular maintenance. The objective is to influence city land use planners, disaster managers, and other decision makers to consider nature-based adaptation solutions to flood risk by allowing them to virtually observe the benefits that mangrove ecosystems can provide to their communities, built infrastructure, and way of life.

What are strengths and limitations?

This app advances the way we collect, visualize, and use flood risk information to improve the resilience of coastal cities. The accuracy and scale of the information provided is dependent on the availability of appropriate input data, and therefore the decisions that can be made using this tool. However, as better data become available, this approach can be calibrated, improved, and leveraged to other regions with similar flood risk and adaptation issues around the world.