Because coastal studies can involve the entire coastline of a state or multiple states as in the case of the Great Lakes Coastal Flood Study, the number of stakeholders who have an interest or relevant information for the study is multiplied dramatically. FEMA must engage hundreds or even thousands of communities. This coordination takes time, but FEMA believes the ultimate product is improved with their involvement.
In addition to the stakeholder engagement and coordination needed, coastal studies are technically complex. Coastal flood studies use sophisticated computer models and complex statistical analyses covering areas that are hundreds of miles across, capturing detailed ground elevations, land characteristics, and modeled surge and waves.
Gathering and formatting the input data requires attention to detail and exacting quality control. Running the models and checking the outputs requires time. Translating the verified outputs into Special Flood Hazard Areas (SFHAs) and Base (1-%-annual-chance) Flood Elevations (BFEs) is the next step, which is guided by FEMA's guidelines and standards. Draft maps must be checked carefully (and revised, when necessary) before Preliminary versions of FIRMs are created and distributed to communities and other stakeholders. Everything must be documented and reviewed.