2 Danish basins with artesian aquifers are investigated. Using data for streamflow, precipitation and temperature, a deterministic conceptual rainfall-runoff-model (NAM) has been calibrated to each of the catchments for a period before and for a period after the development started. Based upon the changes in values of the model parameters the changes in the water balance of the basins are evaluated.-from AuthorDanish basins artesian aquifers data streamflow precipitation temperature rainfall runoff model catchments water balance