Floodplain mapping and the 100-year flood concept, FEMA flood zone designations and the NFIP, levees and detention basins as flood control structures, channel improvements, and non-structural mitigation and floodproofing.
The "100-year flood" is one of the most consistently misread terms in engineering — it is a 1%-annual-probability event, not a scheduled occurrence — and getting that right is the foundation for everything else in flood control practice, from how FEMA maps risk to how a levee or detention basin is actually sized. This module works through FEMA's flood zone system and Base Flood Elevation, structural flood control (levees and their real failure modes, detention basin storage routing), channel improvements and their downstream side effects, and closes with a worked detention-storage sizing example and non-structural mitigation.
By the end of this module you should be able to explain why a detention basin sized only for its own site can still increase downstream flood risk, and why a levee can fail well before floodwater ever reaches its design elevation — both direct extensions of the storage and channel hydraulics Module 2 and Module 3 built.