One of the most important lessons learned from the study of flooding problems is that the potential for flood damage is greatly increased when, through lack of awareness or disregard for the potential danger, unsuitable development takes place in areas subject to flooding. Once the areas where flooding may occur have been identified, measures can be taken to reduce flood risk to people, property and infrastructure. Individuals can consult the maps before buying property or when considering renovation or new construction. Flood-proofing techniques can be applied to new or existing buildings to reduce flood risk. At the community level, measures such as zoning by-laws and regulations can be employed. Using these tools, risks to life and property can be reduced by reserving the flood plain for uses that are less vulnerable to damage from flooding, such as agriculture, parks, recreational areas and parking lots. Zoning regulations can also be used to require that certain conditions be met in those locations where development is permitted in flood hazard areas.
It is well recognized that buildings, bridges, embankments, dykes and similar structures erected on the flood plain obstruct the passage of floodwaters. This can worsen flood conditions in the immediate area and upstream. Flood maps can also be used to avoid placing fill and other obstructions in locations where they may increase upstream flooding.