“iCoast—Did the Coast Change?” Help Identify Coastal Hazards with USGS Aerial Photographs
The U.S. Geological Survey (USGS) has launched a new crowdsourcing application called “iCoast—Did the Coast Change?” that allows citizen scientists to identify changes to the coast by comparing aerial photographs taken before and after storms.
iCoast invites visitors to explore and classify aerial photographs that are part of an extensive collection taken by USGS researchers since 1995. The first project in iCoast focuses on aerial images taken before and after Hurricane Sandy. Viewers can witness the real-world impacts of the hurricane, they can examine places they know and places they have never been, and, perhaps most important, they can help USGS scientists identify and map coastal change after extreme storms by tagging aerial imagery with pre-defined keywords. In doing so, they will help the USGS improve predictive models of coastal change to inform evacuation, preparedness, and mitigation efforts.
Why Coastal Change Matters
Coastal areas are essential to the economic, cultural, and environmental health of our nation. More than half of the U.S. population lives within 50 miles of the coast. Current trends point to increasing numbers of hurricanes making landfall and an increasing number of people moving into coastal areas that are vulnerable to storms.
Our shorelines are constantly changing, and a storm can cause dramatic coastal changes in a matter of hours. As coastal population and development escalate, so will the potential for loss of life, property damage, and economic disruption caused along the coast by extreme storms. Barrier islands and coastal wetlands are the first line of defense for numerous coastal communities, but many of these natural protections are themselves overly urbanized, with beaches and dunes rapidly eroding and thus heightening coastal vulnerability. As a nation, we must face difficult decisions regarding coastal planning, development, and management practices to strengthen our resilience to coastal hazards.
The USGS hurricane research and response activities for the National Assessment of Coastal Change Hazards include collecting storm-surge water levels, taking pre- and post-storm aerial photographs, and conducting laser altimetry (a.k.a., lidar, for “light detecting and ranging”) surveys of pre- and post-storm beach topography to understand the underlying physical processes of coastal-change hazards. These ephemeral data are critical for developing and improving hazard assessments and situational awareness in the immediate aftermath of a storm.
Aerial Imagery of the Coast Before and After Storms
Since 1995, the USGS has acquired more than 140,000 high-resolution oblique aerial photographs of the Atlantic and Gulf coasts after 24 extreme storms (http://coastal.er.usgs.gov/hurricanes/oblique.php). For Hurricane Sandy alone, more than 9,000 aerial photographs were taken a week after the storm. These aerial photographs were taken at a low altitude (approximately 500 feet above the ground at a distance 1,000 feet offshore) to get a detailed look at a small area of the coast.
While the imagery contains valuable information, the USGS does not have the personnel or capacity to analyze all the photographs taken after every storm to ground-truth and validate prediction models. Also, computers cannot yet automatically identify damages and geomorphic changes to the coast from the oblique aerial photographs. Human intelligence is still needed. The USGS decided to launch a citizen-science project to address this need.
The Power of Crowds for Improving Coastal-Hazard Science
“iCoast—Did the Coast Change?” is an interdisciplinary research project that seeks to engage the whole community in coastal-hazard science. The iCoast team (http://coastal.er.usgs.gov/icoast/about.php; scroll down) is targeting many crowds with coastal expertise, including coastal scientists, residents, managers and planners, teachers and students, and people who use the coast or nearshore waters for recreational or commercial purposes.
iCoast asks volunteers to identify changes to the coast by comparing aerial photographs taken before and after a storm, and then selecting simple one-to-three-word tags (for example, “seawall,” “sand on road,” and “dune scarp”). When users hover the cursor over a pre-defined tag, a pop-up box appears to provide text and pictorial explanations to assist the volunteers’ selection of appropriate tags.
Analyzing aerial photographs to identify storm damage helps USGS coastal scientists evaluate and refine their predictive models of coastal erosion and damage caused by extreme storms—steps that are vital to improving the resolution and timeliness of these models. Currently, these mathematical prediction models are derived from dune elevations and predicted wave action during storms. Adding human observations, especially observations of impacts to human systems such as buildings, roads, and other infrastructure, will allow USGS scientists to ground truth their vulnerability assessments and provide better predictions of damage before storms occur.
Ground Truthing Prediction Models with Crowdsourced Data
The USGS has been a scientific leader in developing models with robust predictive capability by providing geospatial probability estimates of coastal hazards on a regional to national scale. Hurricane-induced water levels from waves and storm surge are compared to the coastal topography or elevation of beaches and dunes to determine the probabilities of four types of coastal change:
Immediately before a hurricane makes landfall, USGS scientists rapidly generate coastal-hazard maps showing the likelihood of storm-induced coastal changes in particular regions along the Atlantic and Gulf coasts. (For example, see “USGS Scientists Predict, Measure Sandy’s Impacts on the Coastal Landscape,” Sound Waves, November/December 2012.) These probabilistic assessments are immediately shared to help coastal residents and decision makers understand, prepare for, and respond to coastal hazards in their region. They can help people predict where barrier islands and evacuation routes will likely be washed over in an approaching hurricane and so facilitate better communication among groups preparing for and responding to the storm.
Benefits of iCoast
Citizen-science projects like iCoast serve the cause of open government and open data by actively sharing USGS aerial imagery with the wider public. iCoast also supports the broad objectives of the USGS Natural Hazards Science Strategy to improve communication of hazard-data collection and research knowledge. The crowd-sourced data produced through iCoast will help the USGS improve the accuracy of coastal-erosion prediction models and vulnerability assessments that can inform pre-storm evacuation planning as well as post-storm rescue and recovery efforts.
The iCoast project is also a way to engage the public’s interest in coastal hazards and boost awareness and risk-wise behavior. It is an interactive source for basic coastal-hazard education that can be used during crises as well as non-emergency times to assist the nation in preparing for extreme storms. iCoast allows users to remotely witness the conditions of bridges, roads, and properties along the coast just days after extreme storms. iCoast can also be a great tool for teachers to facilitate science, technology, engineering, and math (STEM) education.
The iCoast application was designed to be reusable for past and future storms. Its initial development was based on aerial imagery taken before and after Hurricane Sandy. The iCoast team anticipates a stronger public interest in volunteering for iCoast immediately after storms.
Now that hurricane season is underway (it started June 1), consider volunteering for iCoast!For additional ways to help the USGS as a citizen scientist, please visit http://txpub.usgs.gov/myscience/.
in this issue:
Help Identify Coastal Hazards with Aerial Photographs on "iCoast" Website