Changes of drainage run-off hydrological regime in glacial lacustrine clays of the karst zone

Long-term data (1976 to 1999 and 2009) on the hydrological regime change of the drainage situated in glacial lacustrine clay loam on clay in the North Lithuanian karst zone are presented in the article. Study data shows that the drainage run-off changed since 1988. Before 1988 the average drainage run-off was by 19 mm higher than 1988, the insignificant difference (Stjudent’s test tact.=0.58