Changes in discharge regime and storage capacity of the springs : implications to springs classification

The paper presents the results of precipitation influence on the discharge regime changes of 6 springs located in south-western Poland and draining a variety of rocks differing in lithology and age. Calculations for the very wet (2010) and the extremely dry years (2015) have shown that the low spring discharges experienced the greatest variations, with the coefficient ofvariation falling between 3-141%. The coefficient of variation for the maximum and average discharges generally does not exceed 90%. The obtained values of the regression coefficient from 0.0016 to 0.1 d-1 and the coefficient of variation (0-33%) indicate a relatively low variability of groundwater resources and the low transmissivity and high storage capacity of the weathering cover. The spring discharge analysis indicates also the drainage of groundwater bodies of various capacity. The maximum values of the storage capacity are several hundred thousand cubic meters, whereas in the lowest spring resources it does not exceed several thousand cubic meters. Three springs have shown a low variability of the storage capacity (Cv = 4-32%), two have indicated a moderate variability (66 and 70%) and one has shown a large variability (135%). The large storage capacity and high hydraulic resistance of the weathering cover does not guarantee the spring recharge during longer periods (summer-autumn) without rain