How does floodproofing of a structure specifically reduce flood damages, as opposed to channel improvements or levees?

Floodproofing of a structure specifically reduces flood damages by modifying individual buildings and their components to withstand the direct impacts of floodwaters, rather than attempting to prevent the flood itself or divert it from an entire area. This approach focuses on making the structure resilient when floodwaters reach it, directly mitigating damage at the building level. There are two primary methods: dry floodproofing and wet floodproofing. Dry floodproofing involves making a building watertight up to a specific flood elevation. This is achieved by applying sealants, coatings, or membranes to exterior walls, and installing removable or permanent barriers over openings such as doors, windows, and utility penetrations before a flood. For example, a homeowner might deploy a watertight panel over a garage door opening. By preventing water from entering the structure, dry floodproofing directly protects the building’s interior, its contents, and mechanical/electrical systems from water damage, mold, and contamination. This preserves the structural integrity and functionality of the building, significantly reducing the cost and time needed for repairs and content replacement after a flood event. Wet floodproofing, conversely, involves intentionally allowing floodwaters to enter parts of a structure while modifying those areas to minimize damage. This is done by using flood-resistant materials below the flood elevation, elevating critical utilities, and installing flood vents. For instance, the lower sections of walls might be constructed with concrete block instead of drywall, and electrical outlets or heating systems are relocated to higher floors or elevated platforms. Flood vents are openings in foundation walls or enclosures that allow hydrostatic pressure from floodwaters to equalize on both the interior and exterior of the walls, preventing structural collapse due to uneven pressure. By designing the lower levels to tolerate inundation and ensuring critical systems are above flood levels, wet floodproofing reduces the costs associated with structural failure and expedites post-flood recovery, even though water penetration occurs. This is in direct contrast to channel improvements or levees. Channel improvements involve altering the physical characteristics of a river or stream channel—such as widening, deepening, straightening, or lining it—to increase its capacity to convey floodwaters more efficiently. The goal is to keep floodwaters contained within the improved channel, thereby preventing them from overflowing and reaching adjacent lands and structures. For example, dredging a river to remove sediment allows more water to flow through without increasing the water level. Levees are engineered earthen embankments or floodwalls constructed parallel to watercourses or coastlines to act as physical barriers, containing floodwaters within their banks and preventing inundation of the protected area behind them. A levee, for instance, might be built along a river to shield an entire town from high water levels. Both channel improvements and levees are large-scale, area-wide infrastructure projects designed to manage the *flowof water or *blockits entry into an area, thereby reducing the *likelihoodof flooding for multiple structures. Floodproofing, however, is a localized, building-specific strategy that accepts the possibility of floodwaters reaching a structure and focuses on mitigating the *damagethat occurs once they do, directly safeguarding the individual building and its contents.