Assessing risk is an inexact science. After all, risk is unknown until something happens, and often times we’re unaware of all of the factors that lead to catastrophic change. While we can’t know every issue that leads to a calamitous occurrence, all of the inputs to these events are spatial in nature, and by amassing information and regularly measuring change, we can make significant improvements in reducing loss of property and loss of life.
Every year there’s a great deal of loss due to a lack of available measurements, and the lack of a system to track and measure thresholds of change correlated to vulnerability. A primary input to such a system is historical data that gives us a good understanding of the inherent dangers of a specific place based on what’s occurred before. What’s also necessary is a high-resolution model that incorporates details about the natural systems that act upon that place.
Perhaps the most high-profile application of geospatial technology for risk analysis is flood mapping, due in large part to the amount of damage that floods cause. Floods are by far the leading cause of natural disaster loss, leading to $50 billion in property damage in the United States in the 1990s alone. In this application, topography and water systems (hydrology) are mapped to understand the risk from flooding for individual land parcels, tied closely to past occurrences. The common floodplain maps are for 100-year flood and 500-year flood occurrences.
The process of mapping for flood takes into account the extent of potential flood inundation based on topography and statistical analyses to predict flood levels. GIS is the tool that takes in historic data, stream gauge information and other sensor inputs in order to delineat a predicted floodplain. The quality of the data that goes into this model is directly proportional to the accuracy that comes out, and subsequently data quality ties to property loss levels and risk of life.
In the United States, flood insurance is mandated, and the act of flood mapping can be highly politically charged. An unfavorable flood plain map can decrease property value or curtail a planned development. However, the costs of not getting these right, and putting too much property and life in jeopardy, far outweigh the economic concerns of cities, developers or individual citizens.
In the industrial age, factories and processing plants with harmful chemicals and unhealthy emissions have been largely sited near neighborhoods of low income residents. GIS has become a major tool for mapping risks of exposure to toxic chemicals, and their correlation to the lower socio-economic strata of our society. Here GIS is used to identify the output and reach of harmful chemicals along with their proximity to lower income neighborhoods in an effort to identify and address these impacts.
The assessment of such areas requires the mapping of social, economic and environmental actions in correlation to industrial polluters. GIS, along with Census data and other demographic inputs, maps out the proximity and is used to analyze the level of impact and benefit that populations have in order to make informed decisions. The resulting analysis can lead to large-scale efforts to mitigate or balance the negative forces on poorer communities.
Earthquakes and Landslides
Earthquakes and landslides pose a large danger in California, which also sees development pressure due to a large population. The lack of warning that comes with such events means that risk assessment and planning are the most important hazard mitigation measures, with accurate mapping and zoning regulations leading to lower loss of life in the event of an incident.
The amount of data that needs to be assessed for such large-scale hazard mapping could only be analyzed through GIS. Here the geological sub-surface data is combined with population and other infrastructure data to come up with detailed assessment of potential damage. The uncertainty about where an earthquake will strike means that there’s very little effort placed into prediction, although new sensor technology and remote sensing platforms could lead to better warning systems.
The realization that our planet is warming leads to a whole new level of risk assessment where the planetary scale of the problem will require entirely new systems and approaches. The planetary network of sensors that will make up the Global Earth Observation System of Systems (GEOSS) will go a long way toward understanding and mitigating the risks from natural disasters that will likely be heightened by global warming.
But the risks are too widespread to really count – taking in agriculture, environment, coastal zones, environmental refugees, water scarcity, energy issues, economic disruption, etc. We face unprecedented change in the period that humans have been on the planet. Yet, if you look back at the history of the planet as a whole, we can begin to understand the level of change that is coming.
Geospatial technologies are uniquely suited to assess and mitigate risk, and this capability is in its infancy. There’s great opportunity to apply these tools to more in-depth analysis and innovative application in order to get a better handle on the pressures that are yet to come.
Note: This column alternates weekly between Vector1 Media editors. Matt Ball is editor Americas/Asia Pacific for V1 Magazine and V1 Energy magazine.
GIS and Risk Assessment: A Fruitful Combination, William W. Hargrove, Daniel A. Levine, Michael R. Miller, Phil R. Coleman, Daniel L. Pack, and Richard C. Durfee
GIS and Risk Assessment, Ajay Lavakare, GIS Development
GIS Methods for Screening Potential Environmental Justice Areas in New England, Chitra M. Kumar, MIT, June 2002
GIS for Earthquakes, ESRI Library, Best Practices
Environmental Justice: Visualization and Analyses with GIS to Facilitate Informed Decisions, Javier Aguilar and Joanne Haracz, 2001 ESRI User Conference paper
Utilizing GIS to Assess Geologic Hazards Focusing on Earthquakes and Landslides by Eric Cyr