Mapping the Zone Improving Flood Map Accuracy (2009) / Chapter Skim
Currently Skimming:
Summary
Summary
Pages 1-6
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 1... ...
To manage flood risk and minimize The charge to the committee is given in Box S.1. future disaster relief costs, the nation invests significant The committee based its findings and recommenresources in mapping flood hazard areas and providing dations on information gathered from presentations, federal flood insurance to residents in communities that publications, and case studies carried out by the comregulate future floodplain development.
|
From page 2... ...
to predict coastal flood elevations. All of the annual chance flood, and it forms the basis for set- inputs have uncertainties that affect the accuracy of the ting flood insurance premiums and structure elevation resulting flood map.
|
From page 3... ...
, develbound on the uncertainty of the base flood elevation oped from airborne and land surveys, is commonly used is approximately 1 foot. For the river reaches studied in flood map production, even though the elevation in North Carolina, a 1-foot change in flood elevation uncertainties of the NED are about 10 times greater corresponds to a horizontal uncertainty in the flood- than those defined by FEMA as acceptable for floodplain boundary of 8 feet in the mountains, 10 feet in plain mapping.
|
From page 4... ...
Finding 2. Coastal flood maps can be improved significantly through use of coupled two-dimensional Benefit-cost analyses have shown that the greatest storm surge and wave models and improved process benefits of more accurate flood maps are avoided flood models, which would yield more accurate base flood losses to planned new buildings and avoided repairs elevations.
|
From page 5... ...
do not yield base flood elevations, results in net costs. Maps that show only floodplain boundaries have This is significant because detailed and limited detailed the disadvantage of implying that every building in studies in North Carolina rely on lidar data, and even a designated flood zone may flood and that every though lidar surveys are expensive, the costs to map building outside the zone is safe.
|
From page 6... ...
For each stream or coastline mile A significant improvement to coastal flood map- studied, metadata should describe what input data, ping can be made by improving the models. Currently, mapping, and modeling methods were used; the date base flood elevations are calculated by combining of mapping; the contractor; and the starting and endstorm surge models with wave models, and using the ing points.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.