Information on groundwater flow patterns is very important in groundwater conservation efforts. The patterns of groundwater flow will also affect the groundwater
chemistry. However, information on this issue in some areas is often neglected or not yet available such as in Kendal district, Central Java Province, Indonesia. This paper presents the groundwater investigations in the Kendal groundwater basin area of Kendal district. The investigations cover geological survey, including 114 points of observation and measurements of shallow wells and deep wells. Groundwater sampling also carried out at 15 points that distributed evenly for groundwater chemical analysis. The results showed that the groundwater flow patterns in Kendal are generally flowed from south to north direction, for both the unconfined aquifer and confined aquifer. Based on the trilinear piper diagram, the groundwater facies for unconfined aquifer consists of magnesium bicarbonate, calcium chloride and mixed types. Whereas in the confined aquifer, the results obtained are of sodium chloride, calcium chloride and mixed types. Some similarities of groundwater facies found between the unconfined aquifer and confined aquifer, indicating an interaction of both aquifers. In addition, ion enrichment from the recharge area to the discharge area found due to the interaction of groundwater with aquifer material based on the stiff diagrams.
