Principle 3: Flood hazards within the state must be identified and the flood risks assessed.
Flood hazard areas change over time through deliberate modification or as a result of natural changes in the watershed or the body of water itself. Flood hazards are varied and widespread, from riverine to coastal to dam/levee failures to tsunami inundation to alluvial fan flooding. An effective state floodplain management program ensures that the flood risks are known and that changing conditions are accounted for. Flood hazard areas need to be identified and delineated in order to:
- Avoid future flood damage and disaster costs
- Apply regulatory criteria
- Inform property owners and the public of possible risks
- Craft mitigation measures for existing at-risk development
Note: The table and figure numbers found below follow the order of those in the full 2025 FPM Assessment report [.pdf] and may not be sequential. Tables can be sorted by clicking on column headings. If tables and/or charts do not load, try refreshing the page.
Principle 3 Highlights
Question 29. Rating FEMA flood data
- Respondents overall positively rated FEMA, indicating coordination with FEMA (91% "good or better") and quality of flood data (81% "good or better") as strengths (Question 29, Table P3.3).
- The primary concern is the length of time to complete a flood study, which scored lowest with 67% rating it "poor or fair" and 0% "excellent," indicating widespread dissatisfaction with project timelines.
- There is also a desire to expand the extent of floodplains mapped, with 24% rating coverage "poor or fair."
Table P3.3. Results for Question 29 – FEMA flood data ratings.
Question 30. Prioritizing state mapping needs & Question 31. Other priority mapping needs
- Updating old flood engineering studies was identified as the most urgent flood mapping need (Question 30, Table P3.4). Overall, 82% rated this as "quite a bit or a great deal" of a priority, emphasizing a widespread agreement on the need for modernization, consistent with its high priority status in 2017.
- In follow up, (Question 31) when asked to list any other priority mapping needs – many states mentioned the need to transition or move toward 2D Base Level Engineering (BLE) mapping or include future conditions and sea level rise. For example, New York highlighted the need to use the Climate-Informed Science Approach (CISA) for future conditions mapping and to inform freeboard.
Table P3.4. Results for Question 30 – How much of a priority for your state are the following mapping needs?
Questions 32-33. U.S. Geological Survey stream-gaging program
- From 2003 to 2025, there is a continuing trend of declining contributions to the U.S. Geological Survey stream-gaging program (Question 32, Table P3.5).
- 56% of respondents in 2025 indicated that their state does contribute funds for this purpose. In 2003, 76% of states contributed funds; by 2010, participation dropped to 69%; and in 2017, it fell further to 65%.
Table P3.5. 2017 and 2025 results for Questions 32 and 33 – Percentage responding “yes” to questions related to stream gaging programs.
Questions 43-45. High Water Marks collection, documentation & use
- Only half the respondents (51%) indicated that their state does collect and document High Water Marks (HWMs) in addition to any USGS post-flood activities to document and map peak flood conditions (Question 43, Figure P3.3); this is similar to the result in 2017 (49%), but significantly down from 2010 (72%).
Figure P3.3. 2010, 2017 and 2025 results for Question 43 – Does your state collect and document high water marks or HWMs in addition to any U.S. Geological Survey or USGS post-flood activities to document and map peak flood conditions?
Questions 63-67. FEMA Cooperating Technical Partner states
- The number of states and territories indicating they are a FEMA Cooperating Technical Partner (CTP) has remained steady since 2010 (82%) and 2017 (87%) with only a slight decrease for 2025 (78%), which could be explained by different states or territories responding (Question 63).
- Among the eight responding states that are not CTPs, responses to Question 67 indicate that staffing and funding limitations are the most significant barriers to CTP participation (Table P3.16).
Table P3.16. Results for Question 67 – Have the following issues prevented your state from becoming a CTP?
Questions 68-69. Status of Base Level Engineering
- When asked which one of the following best describes the status of Base Level Engineering (BLE) in their state (Question 68, Figure P3.4), over half of responding states (56%) reported that BLE data is already available for their state, 31% indicated that they plan to develop BLE data, and 14% reported that they do not have plans to implement BLE in their state.
Figure P3.4. Results for Question 68 – Which one of the following best describes the status of BLE in your state?
Continue to Principle 4 Highlights
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Principle 6 | Principle 7 | Principle 8 | Principle 9 | Principle 10