Flatirons, Inc.
- Surveying, Engineering & Geomatics
A Full Service Land Surveying Company Serving Boulder County And The Colorado Front Range
 |
 |
 |
  |
|
 |
|
 |
|
|
|
 |
|
 |
 |
|
 |
|
 |
|
Flood Zone DeterminationThe FEMA (Federal Emergency Management Agency) prepares Flood Insurance Rate Maps (FIRMs) that depict the extent of Special Flood Hazard Areas (SFHAs) and other thematic features related to flood risk assessment. SFHAs are areas subject to inundation by a flood having a one- percent or greater probability of being equaled or exceeded during any given year (this is also known as a 100-year flood event). This flood, which is referred to as the base flood, is the national standard on which the floodplain management and insurance requirements of the NFIP (National Flood Insurance Program) are based. The mandatory flood insurance purchase requirements of the 1973 National Flood Insurance Act apply only when a structure is located in an SFHA in a community that is participating in the NFIP. Such a structure is required to be insurable by the NFIP under their rules. Even though a portion of the land parcel upon which the structure is planned or built may be within an SFHA, the mandatory purchase of flood insurance is triggered only if the structure itself is within an SFHA. The FIRMs delineate areas of low flood risk (outside the the 500-year floodplain) and areas of higher risk. Areas of higher risk are further delineated into areas of different risk levels. These different areas of risk may be known by different designations, but the descriptions of the SFHA's include the following: FLOOD HAZARD DESIGNATIONSSpecial Flood Hazard Areas
Special Flood Hazard Areas in coastal areas
Flood Insurance Rate Maps continually undergo revisions and updates. When conditions in an area have been changed, either by natural or artificial causes, an new map may be issued. Another source of revision is by letter (Letter of Map Amendment or Letter of Map Revision). Due to this ongoing process of revision, the determination of a flood risk factor from a FIRM should be accompanied by source information including a Community-Panel number and effective date of the mapping. Determining whether a structure is located in an area of special flood hazard requires the examination of the location of the structure in relationship to the areas of special flood hazard as shown on the applicable FIRM. FIRMs do not include all roads within communities, nor do they depict address, property boundary, or structure location information. Additionally, the FIRMs are usually drawn at a large scale covering great areas of land, making precise determinations of flood risk difficult. As a result of these factors, determinations frequently can be made only by using an ancillary source of data, such as a land parcel map, to determine the location of a particular property on the FIRM. These are records that are often contained in a land surveyors records. It is recognized that despite FEMA's best efforts to make the FIRMs as useful as possible, the descriptions of SFHA areas, as depicted by some maps, may, in some instances, not be clear enough to permit lenders to decide with certainty and precision whether or not a subject property is located in such an SFHA area. When flood risk factor determinations are being made by lenders, firms, or individuals (often a surveyor) retained by lenders to assist in these endeavors, collateral data in addition to the FIRM, such as that provided in an elevation certificate, is frequently required. New Elevation Certificate Requirements , The Professional Surveyor magazine archivesPutting Your Mark on the Map , The Professional Surveyor magazine archivesNational Map Accuracy Standards from the U.S Geological Survey |