Maps may be geographical, economic or physical and include various meteorological maps for rainfall, river runoffs and winds. The scale may vary depending on their purpose. Flood maps should make it possible to predict the threatened areas and allow for the planning of defensive measures. It is better to use topographic maps or maps with a horizontal scale because data on height above sea level are very important when determining flood risks and planning flood defence measures. Digital maps combined with GPS are the most useful.
At river basin level, the following are prepared:
– maps of all regions in danger of being flooded: Flood hazard maps
– maps of specific areas where there is a risk of flooding: Flood risk map
Flood hazard maps, at small or/and at large scale, show the expected extent and water levels of a flooded area in three scenarios: a low probability scenario or extreme events, in a medium probability scenario (at least with a return period of 100 years) and a high probability scenario.
As concerns an example of flood hazard maps in Italy, the Po River Basin Authority (AIPO) has been active for long time in identifying and mapping flood hazard areas of the entire catchment of the Po River. AIPO applied a simplified method based on the perimeter of historical floods thus identifying three distinct flood scenarios: low probability scenario (Return period 500 years), medium probability scenario (Return period 100 – 200 years), high probability scenario . (Fig.12.a and Fig.12.b).
Flood risk maps are prepared for the areas flooded under these scenarios showing the population, economic activities and the environment at potential risk of flooding, and other information that may be useful to include, e.g., other sources of pollution.
The maps are used to determine regions which may be affected by floods and the losses which may result. Measures to protect the population and long-term activities to mitigate the potential consequences of flooding are planned on the basis of these maps.
The maps of the regions under threat of a flooding cover the geographical locations that can be flooded and reflect:
- floods that are less likely to occur or cases of unforeseen events;
- floods with medium probability to occur /probability of second occurrence – more than 100 years /;
- floods with high probability to occur.
On the bases of prediction on these maps, several activities with long and short term character aiming to prevent or to reduce flood consequences are planned and implemented and planes for defense are elaborated.
The maps of the regions under risk of flood show the possible negative consequences of the flood and reflect:
- a project number of population that could be possibly affected;
- type of economic activity in the region that will be possibly affected;
- installations for complex prevention and control of contamination, that may cause additional contamination due to flood-caused technical failures.
On the bases of prediction on these maps the activities for protection of the damaged populayion on regional and local level, the long and short term activities are planned. An individual plan for action at flood danger for you and your family can be prepared on the bases of these maps.
You are entitled to familiarize yourself with the maps and to receive the information you require concerning danger of flood, and if a proper organization is in place, to receive such maps or excerpts thereof.
Even more – it is the obligation of every citizen to be aware of what dangers are possible in his living location. It is especially important to familiarize yourself with the map and to check whether the home you live in, the school you study in, or your work place are located in zones in danger of flood. On the basis of that you can request information for the existing protection plan and the steps you need to undertake in case of danger, during, and after a flood.
The maps are prepared, maintained and kept by the respective institutions in a country – normally these would be the Basin directorates and Civil Protection Service.
From the map you can learn about the obligation of the local authorities for prevention from flood at sudden danger from flood.
From the maps you can learn about the obligation of the local authorities for prevention from flood risk and to insist to be implemented.
From the maps on Internet you can get orientation about the existing rivers, springs, dams and other hydro technical facilities which can cause flood.
At school you can create you own map of the danger zones from flooding for the place where you live, the way to school and at school to predict and discuss what you have to do in case of flood if you are any of these places. Before going abroad with your parents on holiday you can learn from the Internet map about the existing danger from some types of floods.
We have prepared a map of the floods all over the world on the bases of “Google Maps”.
You can look at the map and decide whether there is a thread from flood for a place you wish. You may try to make a prediction about the areas threatened by flood. The icons of Google have been used. You can add to any place threatened by flood or hurt by flood: pictures, texts, drawings, videos etc. This map can connect with GPS navigator and we can exactly to the place we want – where we live, the place we will go on holiday with our parents.
View Floods Prevention – ECRP (BG) in a larger map