GIS Technology Now A Critical Tool In Flood Zone Determination


BLOG VIEW: We know that flooding is a major natural disaster that affects many parts of the world, including developed countries such as the U.S. It causes billions of dollars in infrastructure and property damage, as well as loss of life for hundreds each year.

According to Consumer Compliance Outlook, Hurricane Irene alone was estimated to have caused between $7 billion and $10 billion in losses. Hurricane Katrina resulted in claim payments of $16.2 billion from the National Flood Insurance Program (NFIP), ranking it the most expensive flood since the NFIP’s inception in 1968.

Using technology can help predict flooding and potentially save lives and money. The key is to actually use it.

Despite the overwhelming effects flooding has on people and resources around the world, the process of determining if an area is at risk of flooding is manual in many areas. Currently, flood studies are available only as paper documents for several areas around the country.

To respond to a request to determine if a property is located in an area prone to flooding – and if it meets the Federal Emergency Management Agency (FEMA) floodplain management requirements – legal descriptions are used to locate the parcel on an appropriate study, and pertinent information is collected. This process is tedious, lengthy and, not to mention, wastes staff time. It has all of the limitations of paper-based media in terms of archiving, organizing and searching flood studies.

Sometimes, flood studies are divided into parts and represented in several drawings. That’s right – drawings. It is inconvenient to combine these paper drawings so that the whole picture can be seen. It is also challenging to view these studies in conjunction with other data.

This is a long, painstaking, manual process. To use these studies more effectively, FEMA decided to convert them from paper to a digital format so the flood industry could find the information more quickly and to make flood studies accessible to a wider audience. They can now be seamlessly analyzed and explored in the context of other relevant data.

Geographic information systems (GIS) were an obvious answer. GIS technology is successfully used to visualize the extent of flooding and also to analyze the flood maps to produce flood damage estimation maps and flood risk maps. Flood inundation maps are essential for municipal planning, emergency action plans, flood insurance rates and ecological studies.

Converting these flood studies into GIS layers would allow users to take advantage of sophisticated analysis tools to explore them in conjunction with other relevant GIS data. Departments could store these studies in a relational database management system, thus making it possible to do the flood zone determination faster.

Using GIS software, geoprocessing technologies and tools in the industry streamlines workflow and can allow companies to load the digital flood data into an enterprise-level flood database. With more efficient processes in place and using a comprehensive set of GIS spatial layers, a company can maintain a high flood zone automation rate.

This, coupled with business rules and logics, helps achieve higher accuracy on flood zone determinations. In an ideal world, the business rules can be customized to meet the needs of lenders/servicers anywhere and everywhere.

Priscilla Anand is GIS technical manager for LERETA, a provider of flood and tax services.

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6 years ago

Hi Priscilla,

Very interesting article! We have recently done something similar on how our tool could be of great assistance to natural disasters.

Check it out if you’re interested.


Priscilla Anand
Priscilla Anand
6 years ago
Reply to  Siobhan

Hello Siobhan,

Thank you. I really like the features of Mappt, very well done!!!