A floodplain is a normally dry area of land that is susceptible to flooding. These areas are typically adjacent to a stream, lake or river; however, they can also be other low areas that can’t drain as quickly as the rain falls.

• One percent annual chance of flooding zones 
  • Zone A floodplain – No base flood elevations determined by FEMA 
  • Zone AE floodplain – Special Flood Hazard Area (SFHA) has 1 percent annual chance of flooding. Statistically, this area has a 26 percent chance of flooding over the life of a 30-year mortgage, even though the annual chance of flooding is 1 percent.

  Floodway area in zone AE is the channel of a stream, i.e., Minnehaha Creek, plus any adjacent floodplain areas that must be kept free of encroachment so that the 1 percent chance flood can be carried without substantial increases in flood heights. 

• 500-year floodplain (Zone X) – 0.2 percent chance of flooding. Structures in this zone are not required to purchase flood insurance.
• There are additional FEMA-identified flood zones, but they may not be applicable to St. Louis Park.

Common acronyms

The following acronyms are commonly used in flood-related documents and discussions:

• FEMA – Federal Emergency Management Agency
• NFIP – National Flood Insurance Program
• SFHA – Special Flood Hazard Area, also known as the 100-year floodplain
• FIRM – Flood Insurance Rate Map
• CRS – Community Rating System

Natural and beneficial functions of a floodplain

Floodplains with natural and beneficial functions provide an erosion control buffer and open space so further flood damage does not occur. Native plants are best suited for floodplains with deep root systems to resist erosion and stabilize the shoreline. Turf grass has a shallow root system and commonly erodes.

Base flood elevation (BFE) is synonymous with the 100-year flood stage. Determining base flood elevations can be done in different ways depending on the source of the floodplain map and the zone of the site.

• Elevation of surface water from a flood that has a 1 percent chance of equaling or exceeding that level in any given year
• BFE is shown on the FIRM

The City of St. Louis Park participates in the National Flood Insurance Program (NFIP), making federally backed flood insurance available to property owners. Lenders are prohibited from issuing mortgages for properties in the Special Flood Hazard Area (SFHA), unless the property is covered by flood insurance.

Learn more about flood insurance.

The City of St. Louis Park regulates construction, earth work, improvements, repairs and development within the SFHA. Properties that touch the SFHA must comply with floodplain development standards developed by the city.

• Anywhere it can rain, it can flood!
• Rainfall events are and will continue to be more frequent and extreme. 
  • Since 2000, widespread rains of more than six inches are four times more frequent than in the previous three decades in Minnesota. 
  • Rainfall events of more than three inches have increased 65% since 2000 in Minnesota. 
• More than 30% of flood insurance claims in Minnesota are for damage outside of FEMA mapped high risk zones. 
• Close to 50% of flood damage is outside of FEMA mapped high risk zones. 

• Floodplain management (DNR)
• Floodplain description, definitions, management and requirements (DNR)
• What can (and should) I do about fluctuating water levels on my property? (DNR)
• Floodplain management quick guide (DNR)