In this study, the vulnerable period assessment method for weekly groundwater resources management was developed considering correlation between data of groundwater level, river level, precipitation applying critical infiltration concept. The vulnerable periods of 3 case study were assessed using data of groundwater, precipitation, river level, and results were compared . The weights for between observation stations were calculated using correlation of groundwater, precipitation, river level data, and weights that could be considered recently trend of data for each observation station. The vulnerable period was assessed using final calculated weights and multi criteria decision method, compared result for each case study. The developed method can be a quantitative basis for the establishment of efficient groundwater resources management and the decision of specific countermeasure applyment.