The bar chart WW-I-2a ’Groundwater level and spring flow – Northern Region’ indicates – for the years of 1961 to 2021 – the annual number of months in which the highest mean groundwater level was exceeded in the period 1971-2000 and the highest mean spring flow, as well as the number of months in which the lowest mean groundwater level and/or the lowest mean spring flow in the period 1971–2000 were not attained. The indicator refers to the Northern Region which comprises the Länder of Brandenburg, Mecklenburg-Vorpommern. Lower Saxony, North Rhine-Westphalia, Saxony-Anhalt and Schleswig-Holstein from 1971 onwards, there has been an extended aggregate of gauging stations available. By 2021, the number of months indicating non-attainment of the relevant reference value increased significantly. With regard to the same period, the number of months indicating exceedance of the relevant reference value decreased significantly.
