Flood is the most common and is the cause of loss of the social aspects, economy and loss of life worldwide. The increasing settlement in the coastal; areas, river basins and lakeshores also aggravates the losses.  (Shannon Doocy, 2013) Deforestation and climate change increases the frequency and manifolds its impact. Flood losses can be expected to increase fivefold by 2050 and up to 17-fold by 2080 in Europe. (Flood risks and environmental vulnerability, 2016) page number 53

Flood mapping is a crucial element of flood risk management. It is an essential tool to avoid or minimize the damage to life and property caused by flood and for communicating flood risk, however, maps does not prevent floods from occurring. 

Flood hazard map shows the extent and expected water depths/levels of an area flooded in three scenarios, a low/medium and if appropriate high probability scenario or extreme events.

Flood risk map shows the potential population, economic activities and the environment at potential risk from flooding. 

Flood map is useful to establish zoning, land use, and building standards, to support land use, infrastructure, transportation, flood warning, evacuation and emergency management planning, and also to prepare for and respond to floods. Communities can use the map and thus generated data to determine the risk areas, safe evacuation routes and to update the response plan.  

In lack of the potential and accurate flood maps, it affects the development activities in or near the hazard area. The community also lacks tool to guide development to be safer and also to mitigate future losses.

Refer here to learn the methodologies on conducting flood mapping.