Quick2 DOS software version 1.0

Quick2 DOS software version 1.0
Quick2 published by Federal Emergency Management Agency (FEMA)

Sunday, September 22, 2024

FEMA Out-by-LiDAR

 

Using LiDAR For Map Amendments  
LiDAR data can replace the requirement to submit elevation information  
certified by a licensed land surveyor or professional engineer, which can create  
a cost savings for property owners. However, LiDAR data may be less accurate  
than certified elevations and may not capture the full risk for the building or  
lot.  
For more information on the standard LOMA process and requirements,  
DOES MY COMMUNITY HAVE LIDAR?  
Not all communities have LiDAR data available. Talk to your floodplain administrator to find out if your  
community has LiDAR data.  
To be used in a LOMA request, LiDAR data must meet or exceed the U.S. Geological Survey (USGS)  
Quality Level 3 accuracy requirement. To learn more about this requirement, please use the USGS  
LiDAR Base Specification Guide.  
The USGS plans to collect high quality LiDAR data across the United States using a 3D Elevation  
Program (3DEP). For more information on the 3DEP program and current USGS LiDAR availability,  
please visit their 3DEP webpage.  
WHEN LIDAR CANNOT BE USED  
There are situations when LiDAR cannot be used in a LOMA request. These include applications involving  
the following:  
Buildings or lots elevated using fill  
Buildings or lots in the regulatory floodway  
Buildings or lots in Coastal High Hazard Areas (Zone V, VE, or V1-V30)  
Buildings or lots in Zone AO, AR, or A99  
Buildings under construction. LiDAR would need to show that the lot or portion of the lot on which  
building will be located is above the Base Flood Elevation (BFE)  
Conditional determinations  
Electronic LOMAs (eLOMAs)  
Potential violations identified through the LOMA process  
Physical changes to the flooding source/Special Flood Hazard Area that require revisions to the  
Flood Insurance Rate Map  
Requests to supersede previously issued LOMAs based on certified elevation data  
Additional information about LiDAR requirements for LOMAs is available in the  
WHAT NEEDS TO BE SUBMITTED WITH MY APPLICATION?  
When requesting a LOMA using LiDAR data, you must submit a paper map or digital PDF that displays:  
(1) an overlay of the LiDAR contours (lines of equal elevation), or  
(2) an overlay of the LiDAR points (points with specific elevations).  
Either overlay must include an aerial image of the building or lot with at least one street intersection  
shown on the map.  
The map must also have:  
Scale and North arrow  
Source of the LiDAR, including public website  
address. LiDAR must be provided by a Federal,  
State, or local government agency.  
Address or Assessor’s Parcel Number (APN)  
for the building/lot  
LiDAR accuracy information  
Clearly identified building and/or lot boundaries  
Name, organization, and contact information  
for the map overlay creator  
(Does it meet Quality Level 3 standards?)  
Vertical Datum of elevation data (e.g., NAVD 88)  
Location of the data archive or metadata file  
(must be available for independent verification  
through a publicly available website or metadata)  
Aerial imagery that correctly represents the  
footprint of the building  
Date the LiDAR was collected  
Your floodplain administrator or a mapping professional can help you develop the map for your  
application. For other requirements, please use the How to Request a Map Amendment Guide.  
|
DECEMBER 2018  
USING LIDAR FOR MAP AMENDMENTS  
2
CALCULATING ELEVATIONS USING LIDAR  
The lowest adjacent grade (LAG) for a building, or the lowest lot elevation (LLE) for a lot, will be compared  
to the effective Base Flood Elevation (BFE) to determine the flood zone. If LAG/LLE is at or above the BFE  
on the current flood map, FEMA can issue a removal determination. For buildings or lots that cannot be  
removed from the high-risk zone using LiDAR, certified elevation data will be required for a standard LOMA  
determination.  
Using LiDAR Contours  
For LOMA submittals that include LiDAR data contours, FEMA will subtract half the contour interval or  
1 foot, whichever is greater, from the lowest contour closest to (but not going through) the building (to  
determine the LAG) or the lot (to determine the LLE).  
CALCULATING THE LOWEST GRADE (LAG)  
1. Determine the closest contour lower than the building footprint.  
2. Subtract 1/2 the contour interval or 1 ft., whichever is greater to determine the applicable LAG or Lowest Lot Elevation (LLE).  
Elevation 802’  
This structure is Out as Shown (OAS)  
Requests where the FIRM data clearly  
LAG would be 797’  
(closest lower contour  
shows the property/structure to be Out as  
Shown are not eligible for LiDAR review.  
of 798’ - 1’)  
Elevation 800’  
LAG would be 797’  
(closest lower contour  
of 798’ - 1’)  
Elevation 798’  
LAG would be 795’  
(Will Need Field Survey) (closest  
lower contour of 796’ - 1’)  
Elevation 796’  
Zone AE  
Lake BFE = 796.2  
|
DECEMBER 2018  
USING LIDAR FOR MAP AMENDMENTS  
3
Using LiDAR Point Data  
For submittals that include LiDAR point data, FEMA will subtract 2 feet from the lowest point closest to the  
building (to determine the LAG) or the lowest point on the lot (to determine the LLE). Multiple points must  
cover the building/lot for this method.  
365.53  
Zone AE  
Lake BFE = 360.0  
369.09  
369.05  
369.31  
LAG would be 360.77’  
(lowest adjacent  
point -2')  
362.85  
366.38  
367.99  
369.49  
371.34  
370.68  
363.62•  
364.94•  
362.77•  
371.8  
373.18  
367.68•  
374.35  
374.58  
374.56  
374.58  
371.57  
372.24  
370.11  
WHERE DO I GO IF I NEED HELP?  
To speak with a Map Specialist about the amendment process, contact the FEMA Map Information  
eXchange (FMIX) at 877-FEMA-MAP (877-336-2627) or FEMAMapSpecialist@riskmapcds.com  
|
DECEMBER 2018  
USING LIDAR FOR MAP AMENDMENTS  
4

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