530 Flood Protection
400 Mapping and Regulations

530
Flood Protection

When buildings cannot be acquired or moved out of high-hazard areas, an alternative can be to protect them from flood damage with flood control structures or by retrofitting them.

532.a
Flood protection project technique used (TU)

Level of effort = moderate

Overview

The 530 activity elements address the work that you do to protect individual buildings in your community through retrofitting or small flood control projects. Element 532.a specifically focuses on retrofitting techniques. The range of measures covered under this umbrella include elevating buildings, dry floodproofing, wet floodproofing, protecting basements from sewer backup, and physical barriers. Because elevation is, by far, the most effective mitigation technique, it is awarded more credits.

530 is a bit tricky because credits are determined at the activity level using values that are defined at the element level. This element defines Techniques Used (TU) using the following acronyms:

Acronym Technique
TUE Elevation
TUD Dry floodproofing
TUW Wet floodproofing
TUS Sewer backup
TUB Barrier, levee, or floodwall
TUC Channel modification, storm sewer improvements, diversions
TUF Storage facilities

To determine the value for each of these techniques, refer to your CRS Coordinator's Manual. The values calculated in this element are combined with those calculated in the next element (532.b) in the calculation for a PB value in 532.c.

Considerations

Credits are calculated for each protected building and there are a few restrictions on which buildings in your community qualify:

  • Buildings are not counted, even though they are protected, if they exist outside of the regulatory floodplain unless they are repetitive loss properties.
  • Buildings must be insurable and completed after the initial FIRM date.
  • Protection projects must protect against a 25 year flood at a minimum
  • Accessory structures are not counted as buildings for this activity.
  • Projects that are unmaintained or in disrepair will not be counted.

Documentation

For this activity overall, you must provide:

  • Copies of the elevation certificates (for elevations)
  • A list of the buildings with a signed CC-530EHP Flood Protection form (other retrofits)
  • For flood control projects, the level of flood protection before and after the project (ex: 25 year storm) and a letter from the state dam safety office (for reservoirs, detention or retention)
  • A map of all of the protected buildings
  • Documentation of the implementation date of each project, including Certification of Compliance with Environmental and Historic Preservation Requirements for Acquisition and Relocation Projects (CC-520EHP)
  • The total number of buildings in the Special Flood Hazard Area (SFHA) (if using Option 2 in the credit calculation)
  • A copy of the request for Conditional Letter of Map Revision (CLOMR), if applicable

Credit Calculation

At the 530 activity level, there are two options for calculating credits:

Option 1: Max: 160, this option is the simplest but the cap is relatively low. You should use this calculation if a small percentage of buildings in the Special Flood Hazard Area (SFHA) have been protected. It can be calculated as follows:

2.4 x (the number of buildings that qualify for Activity 530 credit x the TU credit determined through 532.a)

Option 2: Max: 1,600, This option is based on the percentage of buildings left in the Special Flood Hazard Area (SFHA). You should use this calculation if a large percentage of buildings in the Special Flood Hazard Area (SFHA) have been acquired or relocated (more than 30%). IT can be calculated as follows:

16 x ((the sum of all PB calculated in 532.c x 100) / the number of buildings in the SFHA)

Credits can be modified if properties are repetitive loss, severe repetitive loss, or critical facilities.

For more information on calculating 530 credit, contact us.

532.b
Flood protection improvement (FPI)

In addition to retrofits, Activity 530 also takes into account additional flood protection measures.

Level of effort = low

Overview

For buildings that were protected using enhanced flood protection measures, an adjustment is made to incorporate the difference in protection.

Again, for 530, credits are determined at the activity level using element values. Flood Protection Improvement for a given building (FPI#i) is calculated as follows:

flood protection provided by the project (FPP) - flood protection level before project construction (FPB)

To determine values for FPP and FPB, use the following table:

Flood Protection Level FPP or FPB Value
< 10-year flood 0.0
10-year flood - 25-year flood 0.3
25-year flood - 50-year flood 0.5
50-year flood - 100-year flood 0.7
100-year flood 0.8
100-year flood + 1 ft. freeboard 0.9
100-year flood + 2 or more ft. of freeboard 1.0
500-year flood 1.0

Note that for FPP, the minimum value is 0.5 as you cannot receive credit for flood protection measures that address flooding conditions less than the 25-year flood level. The values calculated in this element are combined with those calculated in the previous element (532.a) in the calculation for a PB value in 532.c.

Considerations

Credits are calculated for each protected building and there are a few restrictions on which buildings in your community qualify:

  • Buildings are not counted, even though they are protected, if they exist outside of the regulatory floodplain unless they are repetitive loss properties.
  • Buildings must be insurable and completed after the initial FIRM date.
  • Protection projects must protect against a 25 year flood at a minimum
  • Accessory structures are not counted as buildings for this activity.
  • Projects that are unmaintained or in disrepair will not be counted.

Documentation

For this activity overall, you must provide:

  • Copies of the elevation certificates (for elevations)
  • A list of the buildings with a signed CC-530EHP Flood Protection form (other retrofits)
  • For flood control projects, the level of flood protection before and after the project (ex: 25 year storm) and a letter from the state dam safety office (for reservoirs, detention or retention)
  • A map of all of the protected buildings
  • Documentation of the implementation date of each project, including Certification of Compliance with Environmental and Historic Preservation Requirements for Acquisition and Relocation Projects (CC-520EHP)
  • The total number of buildings in the Special Flood Hazard Area (SFHA) (if using Option 2 in the credit calculation)
  • A copy of the request for Conditional Letter of Map Revision (CLOMR), if applicable

Credit Calculation

At the 530 activity level, there are two options for calculating credits:

Option 1: Max: 160, this option is the simplest but the cap is relatively low. You should use this calculation if a small percentage of buildings in the Special Flood Hazard Area (SFHA) have been protected. It can be calculated as follows:

2.4 x (the number of buildings that qualify for Activity 530 credit x the TU credit determined through 532.a)

Option 2: Max: 1,600, This option is based on the percentage of buildings left in the Special Flood Hazard Area (SFHA). You should use this calculation if a large percentage of buildings in the Special Flood Hazard Area (SFHA) have been acquired or relocated (more than 30%). IT can be calculated as follows:

16 x ((the sum of all PB calculated in 532.c x 100) / the number of buildings in the SFHA)

Credits can be modified if properties are repetitive loss, severe repetitive loss, or critical facilities.

For more information on calculating 530 credit, contact us.

532.c
Protected buildings (PB)

Level of effort = moderate

Overview

The values determined in 532.a and 532.b are combined in this element to produce a Protected buildings value (PB). PB is then utilized for the calculation detailed in "Credit Calculations" below. To calculate PB, use the following formula:

TU x FPI#i

Multipliers for repetitive loss properties and severe repetitive loss properties can be applied.

Considerations

Credits are calculated for each protected building and there are a few restrictions on which buildings in your community qualify:

  • Buildings are not counted, even though they are protected, if they exist outside of the regulatory floodplain unless they are repetitive loss properties.
  • Buildings must be insurable and completed after the initial FIRM date.
  • Protection projects must protect against a 25 year flood at a minimum
  • Accessory structures are not counted as buildings for this activity.
  • Projects that are unmaintained or in disrepair will not be counted.

Documentation

For this activity overall, you must provide:

  • Copies of the elevation certificates (for elevations)
  • A list of the buildings with a signed CC-530EHP Flood Protection form (other retrofits)
  • For flood control projects, the level of flood protection before and after the project (ex: 25 year storm) and a letter from the state dam safety office (for reservoirs, detention or retention)
  • A map of all of the protected buildings
  • Documentation of the implementation date of each project, including Certification of Compliance with Environmental and Historic Preservation Requirements for Acquisition and Relocation Projects (CC-520EHP)
  • The total number of buildings in the Special Flood Hazard Area (SFHA) (if using Option 2 in the credit calculation)
  • A copy of the request for Conditional Letter of Map Revision (CLOMR), if applicable

Credit Calculation

At the 530 activity level, there are two options for calculating credits:

Option 1: Max: 160, this option is the simplest but the cap is relatively low. You should use this calculation if a small percentage of buildings in the Special Flood Hazard Area (SFHA) have been protected. It can be calculated as follows:

2.4 x (the number of buildings that qualify for Activity 530 credit x the TU credit determined through 532.a)

Option 2: Max: 1,600, This option is based on the percentage of buildings left in the Special Flood Hazard Area (SFHA). You should use this calculation if a large percentage of buildings in the Special Flood Hazard Area (SFHA) have been acquired or relocated (more than 30%). IT can be calculated as follows:

16 x ((the sum of all PB calculated in 532.c x 100) / the number of buildings in the SFHA)

Credits can be modified if properties are repetitive loss, severe repetitive loss, or critical facilities.

For more information on calculating 530 credit, contact us.

This CRS guide was produced by CRS professionals and Certified Floodplain Managers to help you navigate the Community Rating System. It is not meant to replace FEMA's official CRS Coordinator's Manual, nor should it supersede the instructions given by your ISO/CRS Specialist.

For additional resources, visit https://crsresources.org/ .