Is your house in the flood zone?

The line the state drew#

The blue is the area that Apele Române, Romania's national water authority, shows under water in a flood that comes on average once in 100 years, shaded by depth: the darker, the deeper. The maps were first published in 2013 and redone in 2022 under the EU Floods Directive; the state uses them for flood defence plans and for town planning.

In Oradea, a county seat in north-western Romania near the Hungarian border, the line runs through town on both banks of the Crișul Repede river.

Roofs in the water#

Red marks every building inside that zone. In Oradea there are 13,254, 36 per cent of all buildings in the city; at 3,373 of them the water would be more than a metre deep.

Nationally, 378,920 buildings stand in the once-in-a-century zone, 3.4 per cent of the 11,089,350 buildings on the footprint maps. The count includes outbuildings such as barns, sheds and garages; 270,788 are larger than 50 square metres, the size of a small house. At 94,484 of them the map shows more than a metre of water.

The footprint maps are not flawless: when footprints drawn at random inside the first maps' zone were checked on satellite images, 19 per cent of those that could be seen clearly turned out to be shadows, greenhouses or patches of field. The numbers here count mapped footprints.

Whole villages#

In cities the flood zone takes neighbourhoods. In the countryside it can take nearly everything. In Milcovul, a rural commune of several villages in Vrancea county, 2,487 of 2,785 buildings (89 per cent) are inside the once-in-a-century zone.

Buildings in the zone are found in 1,760 communes and towns; 77 of them have more than a thousand. The county with the most is Bihor: 31,299.

Building went on#

The first maps were published in December 2013. To see how much has been built since their time, 300 buildings were drawn at random from inside their zone and 300 from land outside any flood zone within 500 metres of it, then compared on satellite images from 2010–2014 and from 2020 on, without knowing which group each came from. Inside the zone, 230 could be seen clearly and were buildings; 17 of them (7 per cent) were not there on the old images. Just outside, 24 of 259 (9 per cent).

The gap is within chance (a ratio of 0.8, with a margin from 0.4 to 1.4): inside the flood zone the share of new buildings is not clearly lower than next to it. Scaled to the whole zone of the first maps, that is around 16,100 buildings that appeared after the 2010–2014 images (between 10,100 and 25,200), some of them before the maps were published.

What the law says#

Article 49 of Romania's Water Law bans new homes and their outbuildings in a river's floodplain (the ‘albia majoră’ of Romanian law). The exception is new buildings that come with flood-defence works, approved by Apele Române.

Since 2013 a government decision has required the hazard maps to be written into town plans. Yet the European Court of Auditors noted in 2018 that Romanian law does not tie its notion of a flood zone to these maps. A house in the blue is therefore not illegal for that reason alone; this page does not see building permits, which are held by town halls.

Where the map stops#

The 1-in-100 map keeps existing dikes standing: water can spill over them but they do not break. Apele Române also modelled dike breaches, but those layers are empty in its public map service. Land reached by water spilling over a dike is in the zone; land that would flood only if a dike broke is not shown.

The maps cover the rivers the state judged to carry significant risk, not every stream. Flash floods off hillsides, sewers that cannot take the rain and small brooks can flood outside the line. Outside the zone does not mean safe; inside does not mean the water will come. Emergencies are handled by the county emergency inspectorate (ISU), the maps by Apele Române, permits by the town hall.