Monthly maps for discharge anomalies and Lowest alert level exceedance with a summary of the monthly hydrological situation.


Hydrological situation for September 2021

Figure 1. Exceedance of lowest discharge threshold level for September 2021.
Figure 1. Exceedance of lowest discharge threshold level for September 2021.
Figure 2. Exceedance of lowest water level threshold level for September 2021.
Figure 2. Exceedance of lowest water level threshold level for September 2021.
Figure 3. Classification of stations according to discharge historical data average percentile ranges for September 2021.
Figure 3. Classification of stations according to discharge historical data average percentile ranges for September 2021.

by EFAS Hydrological Data Collection Centre,

In September, Poland was the country with the highest concentration of stations exceeding their threshold level (36 stations), with stations distributed in the Vistula and Oder basins. In Spain, 18 stations exceeded their threshold, specifically in the east of the country (Llobregat, Ebro, Jucar, Turia, Seco, Algar, Barranc de Torrent, and Serpis basins). Also remarkable is the situation in the Po river basin in Italy, with exceedances in 16 stations, and the situation in central Italy, with one station in the Garigliano river basin. In Germany, the exceedances occurred in nine stations located in the Danube river basin and one in the Elbe. In a more dispersed way, the Danube basin contains three other stations distributed across Austria and Croatia, and along the border between Croatia and Serbia. Norway, Iceland, Belarus, and Ukraine also experienced some isolated stations exceeding thresholds.

Regarding stations registering values above the 90% quantile, 160 stations exceeded this value in September. The majority of these stations were located in central Europe. Nearly 26% of these stations were in the Danube basin throughout Austria, Serbia, Slovakia, Germany, Czech Republic, Bulgaria, Hungary, Romania, Serbia, and Ukraine. This is followed by the Rhine basin with 18 stations in Switzerland, France, and Luxembourg. It was also noteworthy in Spain, where the following basins have stations which values are above the 90% quantile: Ebro (13 stations), Guadalquivir, Minho, and Jucar. France is also notable with 19 stations surpassing the 90% quantile, mainly located in the Loire basin. Another considerable number of stations also exceeding the 90% quantile can be seen in the Elbe, Dnieper, Oder, and Vistula basins. To a lesser degree, other stations over their 90% quantile were in basins located in Norway, Finland, Sweden, and England. Isolated stations exceeding the 90% quantile occurred in other stations in Ukraine, Italy, Slovenia, Switzerland, and Ireland.

Finally, and according to those stations registering values below the 10% quantile (36 in total), the highest concentration of them corresponded to southern Norway where 12 stations reached these values. In a more dispersed pattern, we can find 7 stations across the western and central Danube basin, located in Hungary, Slovenia, Austria, Bosnia-Herzegovina, Serbia, and 7 more stations along the Loire, Dordogne, Adour, Aude, and Rhône basins in France. A lower density of stations occurred in Spain (where 5 stations are spread throughout the entire country), the Trent basin in England (2 stations), and Luxemburg (2 stations). Lastly, we can also find an isolated station with values under the 10% quantile in the Vipava river in Slovenia.