美国政府的官方网站
知道是官方网站的原因
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock ( LockA locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. .
提供基本洪水标高的基本洪泛区。现在新格式的FIRM上使用AE区,而不是A1-A30区。