Hydrological situation for May 2023
by EFAS Hydrological Data Collection Centre
During the month of May, there were 228 stations with exceedances, twice than the previous month. Most of them are in Italy (41 stations) and Croatia (32 stations), all of them related to water level. In Slovenia and Bosnia and Herzegovina there are 24 and 23 stations with exceedances respectively. Germany, Sweden, and Austria also stand out with exceedances at more than 10 stations each.
In addition, there are 10 stations in Spain and Poland, nine stations in Ukraine and Switzerland and six in Hungary. Several countries have recorded less than five exceedances this month: Serbia (4), Slovakia and Czech Republic (3) and Iceland and Belgium (2 each).
As for the river basins, the main river basin with values above the threshold is again the Danube, with 112 stations in 10 different countries, with Croatia and Slovenia standing out with 30 and 23 exceedances, respectively. The Po River in Italy is the next river basin with the highest number of stations (33), followed by the Rhine River with 10 stations with exceedances. A total of 44 river basins have exceedances in May.
In terms of the stations that recorded values of mean discharge above the 90% quantile, 87 exceeded this threshold this month, less than the previous month. In May, England was the country with the most stations (15) in this situation. Croatia (13) in this situation, and Slovenia (12), are the countries with the next highest number of stations. The British stations are distributed in six different basins, highlighting the Thames River, with seven stations in this situation. In Croatia, three river basins are affected, notably in the Danube river the one with more stations, 11 of 13, while in Slovenia we find two basins, highlighting the Danube river basin. In Spain, 11 stations show values above this quantile. In Germany, 10 stations exceed this cliff. Other stations exceed the 90% quantile value in up to 15 countries.
By river basin, it is the Danube River that stands out with 41 stations above the 90% quantile. The aforementioned Thames river basin is the second with the highest number of stations over this cliff, showing seven stations in this situation and followed by the Guadiana river basin with 5. A total of 23 different river basins have exceedances over the 90% quantile in May.
Finally, and according to the number of stations recording mean values below the 10% quantile, in May there were 79 stations with average values below this cliff, throughout 11 different countries.
Again this month, Spain is the country with the most stations (54), followed by France (5). Poland has 3 stations with values below this threshold. With two stations we find Ukraine and Italy. Another six countries show only one station each in this situation.
In terms of river basin, again this month the Ebro is the river with the highest number of cases, with 27 stations with an average discharge below the 10% quantile. The Duero River has 8 stations, and Guadalquivir and Llobregat rivers have five stations each in the same situation. All these basins are in Spain, where other five rivers are affected. In total, as many as 22 different basins have values below this limit in Europe.