Flood maps
Introduction
The National Flood Zone Mapping System, also called SNCZI, is a tool that allows you to view the delimitation studies of public hydraulic domain and the mapping studies of flood zones prepared by the Ministry of Agriculture, Fisheries and Food; the Ministry of Ecological Transition; and the respective ministries of the governments of the different autonomous communities of Spain.
Legal framework
Directive 2007/60/EC of the European Parliament[1] and of the Council of October 23 regarding the assessment and management of flood risks, establishes the obligation of each Member State to prepare hazard maps and risk maps of the geographical areas that could be flooded according to the following scenarios:[2].
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- High probability of flooding (return period equal to 10 years, T=10 years).
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- Frequent probability of flooding (return period equal to 50 years, T=50 years).
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- Average or occasional probability of flooding (associated with a return period of 100 years, T=100 years).
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- Low or exceptional probability of flooding (return period equal to 500 years, T=500 years).
In addition to the aforementioned scenarios, article 6 of said directive indicates the elements that must be indicated in the hazard maps:.
• - Extension of the flood.
• - Water drafts or water level.
• - Speed of the current or the corresponding water flow.
On the contrary, risk maps should indicate the potential adverse consequences associated with flooding in the scenarios already mentioned:
• - Number of inhabitants that may be affected.
• - Type of economic activity in the area that may be affected.
• - Facilities that may cause accidental contamination in the event of flooding.
• - Protected areas that may also be affected.
• - Any other information that the Member State considers useful.
The directive was transposed into Spanish legislation through Royal Decree 903/2010 of July 9 regarding the evaluation and management of flood risks, dedicating chapter III to hazard and risk maps, describing the following aspects:[3][4].