by Angela Parker, AICP, CFM / Western Planner Board President-Elect

On June 29, 2020, First Street Foundation released what USA Today calls, “A new, nationwide flood modeling tool (Bagenstose, et al, 2020)." What is First Street Foundation, and what does their new flood modeling tool do?

According to their website, First Street Foundation is a non-profit organization with a large team of talented individuals (firststreet.org/team). Part of First Street Foundation’s mission states,

…FEMA maps were not created to define risk for individual properties. This leaves millions of households and property owners unaware of their true risk. There has long been an urgent need for accurate, property-level, publicly available flood risk information in the United States. In a mission to fill that need, First Street Foundation has built a team of leading modelers, researchers, and data scientists to develop the first comprehensive, publicly available flood risk model in the United States (https://firststreet.org/mission/).

As a Certified Floodplain Manager (CFM), I was curious about this new tool, so I went to floodfactor.com to check it out. I entered my home address to see what I could find. The results were very easy to read and the information was helpful. The sections included are:

Summary
Flood Depth Explained
Flood Risk Explorer
Environmental Changes
Personal Solutions
Area Risk Overview.

Most important is the Flood Factor, which is shown at the top left of the page and is one of the main purposes of the tool. I did notice that even for properties with a Flood Factor of 1, flood insurance is still recommended (see below).

The Flood Depth Explained section provides a visualization that helps you understand the damage that small amounts of water can cause to a home. The Flood Risk Explorer section includes an interactive map where you can view other properties to see the potential risk that others in your area may face. You can view the current risk, as well as potential risk in the future. I was disappointed to find that you can’t click on the map to look at detailed information for another property—instead, you have to enter the address up at the top of the page and start over. It was also difficult to determine property lines, since a parcel layer is not included and the map cannot be further customized. The maps do not provide a scale or a legend, and they are not printer-friendly, either.

To see how well the tool worked, I entered several addresses of family and friends. Out of 20 addresses, I was able to see results on 12 of them. The ones that were not found either showed me the nearest location or just stated “unable to find…please try another location”. These were not new addresses, and were not necessarily rural locations. For large properties, the pin drops in the middle of the property, not necessarily where the structures are located.

One property that I looked up is irrigated, and the map has it listed as “protected by ditch” as if the irrigation canal is actually flood protection, which it is not (see below). If you live in Hawaii or Alaska, don’t even try to enter your address—only the contiguous 48 states are searchable in this tool. Having lived in Alaska for six years, I found this very frustrating.

I entered one business address, which turned up the statement “unable to find, showing the nearest location”. It was pretty accurate, because the pin was across the street from the actual location of the business. However, the aerial photography was over seven years old, noted because a shop building constructed in 2013 was non-existent in the aerial photography.

I also entered City, State information to see what came up. When addresses are entered, the FEMA flood zone layer is visible; however, when City, State is entered, the FEMA flood zone layer is not visible. City boundaries are not included on the map, and no customization is available. There are different colored dots that show properties’ Flood Factors as determined by the Flood Factor tool. Once you have entered a city/state, you can zoom in, but the tool does not allow you to select a specific property. You have to start over by entering an exact address. Entering a state name results in no action—the program simply doesn’t respond, which is understandable since most people want more detailed information that can’t be found at the state level.

I noticed that the Flood Depth Explained and Personal Solutions sections were generalized because they provided the same information for each address I looked up. The Area Risk Overview section provides information on future problems for the address entered, as well as the applicable county and state; every address I viewed included information in this section that indicated flooding would increase in the future.

I searched the website to find metadata for the information provided, such as the year of the aerial photography used and where it came from, but it was difficult to find. The website includes an article regarding the methodology, which states in part,

The sources utilized in each region may vary, but are generally a mosaic of individual county digital elevation model (DEM) projects, post-hurricane LiDAR collection runs by the National Oceanic and Atmospheric Administration (NOAA), and any mapping project that has contributed to the National Elevation Dataset (NED) managed by the United States Geological Survey (USGS). Wherever possible, digital elevation models with a 1-meter horizontal resolution are preferred.
After acquiring the best available data for each region, the data is unified into the same geographic coordinate system (NAD 1983) and vertical datum (NAVD88 in centimeters). Elevation projects are then mosaicked together giving priority to the most recent, highest resolution, and accurate projects (Porter, et al, 2019).

The website includes a methodology overview, which provides some detail about the creation of the Flood Factor tool and states that the model hazard layers are validated through thorough review of the output, and compared to FEMA flood maps. Building data comes from Mapbox, which sources its information from Microsoft and OpenStreetMap. (June 29, 2020, First Street Foundation). More details can be found throughout the pages of First Street Foundation’s website, firststreet.org.

In my role as a CFM, I have used FEMA’s Map Service Center (MSC) many times to create “FIRMettes” for flood zone determination reports. I have found that the MSC is very easy to use, shows property boundaries, and can be printed out. The MSC printout includes a legend that helps the reader understand what they are looking at on the map (See example FIRMette below).

The Association of State Floodplain Managers (ASFPM) sent an email to its members regarding the new tool. It states, in part:

Knowledge is power and ASFPM certainly supports any scientifically sound initiative that helps consumers make more informed decisions when it comes to flood risk. However, a tool like Flood Factor cannot replace the FEMA floodplain maps, which result in $2.45 billion/year in losses avoided from the implementation of NFIP standards alone (and these are inherently tied to the boundaries and data on the FEMA flood maps). As an association, we are concerned that consumers may rely on this new tool exclusively, causing them to make important financial decisions based on generalized data. In fact, the First Street Foundation states that "Federal Emergency Management Agency (FEMA) flood maps are the gold standard for understanding flood risk in the U.S." (Association, 2020).

ASFPM further suggests coordination between floodplain managers and lenders, determination companies, insurance companies and realtors to inform them they may have clients wanting to leverage this new tool if they think it may provide a more favorable outcome in regards to flood insurance requirements (Association).

As with any new software program, the usefulness of the Flood Factor tool will likely improve with time. Overall, the tool is useful for generalized information to help the public understand the risk of flooding, and to get an idea if their property may be at risk. Ultimately, however, federal, state and local regulations will determine the flood risk and related restrictions for each individual property. If in doubt, visit your local floodplain manager at the city or county offices near you!

References

Association of State Floodplain Managers (ASFPM). “Important Talking Points on the First Street Foundation Flood Risk Model.” Received by Angela Parker 26 June, 2020.
Bagenstose, K; Pulver, D; Crowe, K. (June 29, 2020). Millions of Americans think they’re safe from flood waters. They aren’t. USA Today. Accessed at https://www.usatoday.com/in-depth/news/investigations/2020/06/29/realHYPERLINK "https://www.usatoday.com/in-depth/news/investigations/2020/06/29/real-estate-millions-more-homes-risk-flood-might-need-insurance/3217450001/"-HYPERLINK "https://www.usatoday.com/in-depth/news/investigations/2020/06/29/real-estate-millions-more-homes-risk-flood-might-need-insurance/3217450001/"estate-millions-more-homes-risk-flood-might-need-insurance/3217450001/.
First Street Foundation, Defining America’s Flood Risk. First Street Foundation, 2019. Firststreet.org. Accessed July 2020.
First Street Foundation Flood Model 2020 Methodology Overview. June 29, 2020. Accessed from firststreet.org/flood-lab/research/flood-model-methodology_overview/.
Porter, J. Lewis-Gruss, S. Freeman, N. Chu, Z. (March 28, 2019). First Street Foundation 2018 Coastal Tidal and Surge Flood Model Technical Methodology. Accessed from firststreet.org/flood-lab/research/methodology/.

Angela Parker, AICP, CFM is the president elect of the Western Planner Resources board. She is a Certified Floodplain Manager and previously worked as the Platting Officer with Fairbanks North Star Borough Community Planning in Alaska. She also serves on the Wyoming Planning Association Board.

Flood Factor: Review of a New Online Modeling Tool