Floodplain Mitigation: Elevation or By Map



If you’re wondering, what is floodplain mitigation? Let’s discuss it.


In environmental engineering, the flood mitigation involves the management and control of flood water movement, such as redirecting flood run-off through the use of floodwalls and flood gates, rather than trying to prevent floods altogether. It also involves the management of people, through measures such as evacuation and dry/wet proofing properties. 


The prevention and mitigation of flooding can be studied on three levels: on individual properties, small communities, and whole towns or cities.


Floodplain Mitigation can be determined in two different ways, by elevation or by map. That can seem confusing as elevations are provided on both a survey and a FEMA map, but there is a distinction. 


FEMA provides the base flood elevations required for that area and the boundary of the flood zones. Surveys provide the existing elevations which show how the floodwaters presently flow and (post-design) how they will flow on that specific site.


Depending on how the municipality interprets these maps and elevations they can require different design solutions. If by elevation, the boundary of the flood zone affects the base flood elevation, but the proposed elevations and flow pattern can also affect the amount of mitigation that will be required.


If based solely on FEMA maps, then the area of mitigation required relies solely on the development located in that specified flood zone.


If you’re working on a project, be sure to find out early how the entity is addressing the 100-year floodplain compared to the 500-year and how that affects building elevation and mitigation on-site.


Mitigation is an important aspect of a build and with expert civil engineers like PRD Land Development, you will be sure that the right method is being utilized and all considerations are being taken care of.


Have a question? Reach out to us at info@prd-llc.com today!

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