by EFAS Hydrological Data Collection Centre,

During April, stations with threshold exceedances have been less than in previous months. A concentration of stations in central Europe stands out, specifically in the basins of the Dnieper River (Romania and Ukraine) and the Vistula River (eastern Poland), and in Italy (Po river basin). Isolated stations with threshold exceedances are located in the Danube river basin (4 stations in Serbia, 4 in Slovenia, 2 in Romania, 1 in Hungary, 1 in Austria, and 1 in Slovakia). Finally, in Spain, there are 5 stations with exceedances: one in the Minho-Limia basin, another in the Llobregat basin, and three in the Levante area (Júcar, Seco, and Serpis basins).

Regarding stations registering values above the 90% quantile, a minority of the stations (32) exceeded this value in April, half as many stations of that in March (64). A considerable number of these stations (roughly 38%) were located in Poland, principally in the Vistula basin (where 25% of all stations were placed) and in two stations in the Oder basin. Another sizeable portion of stations also surpassing the 90% quantile (just over 34%) can be found in the northern part of the Scandinavian countries, where the vast majority of stations were located in Sweden (6 stations), followed by stations in Finland (3 stations) and Norway (one station in the north and one isolated station in the south). A handful of stations exceeding the 90% quantile are located in the southern basins of Spain (three-quarters were in the Guadalquivir basin), in the Danube basin (on the final stretch of the river) through Serbia and Bulgaria, and in an isolated station at the headwaters of this river basin (Austria). Other isolated stations can be seen in Ukraine (Dnieper basin) and England (Thames basin).

At last and focusing on those stations registering values below the 10% quantile, the vast majority are concentrated in two areas. The first area is the southern part of Germany where 25 stations are spread between the Danube and Rhine basins. The second area is located in the north of Spain, summarizing a total of 16 stations along the Minho, Ebro, and Ter basins. In a more dispersed pattern, we can also find a total of 14 stations located in the German area of the Elbe basin, the central Danube basin (Austria, Slovenia, and Hungary), the south-western Rhine basin (Switzerland and France), the Dnieper basin in Ukraine, the Glomma basin in Norway, and in Poland (Vistula and Oder basins). Finally, we can also find isolated stations with values under the 10% quantile in the Verde river (Spain), Mulkear river (Ireland), Wreake river (England), and Garonne river in France.