Abstract
Water that infiltrates bedrock is not recorded at outlet weirs, and studies have reported that in some catchments this deep percolation cannot be ignored. In this study, we used the chloride mass balance method to estimate deep percolation in a 1-ha mountainous catchment in a Tertiary formation. We determined the chloride concentrations of throughfall, stemflow and streamwater during baseflow and stormflow, and groundwater. The analysis of chloride inputs and streamwater output indicated that the annual deep percolation was in the range 410 to 640 mm/yr and the mean annual percolation was 530 mm/year, or 22 % of the annual mean precipitation. The input of throughfall and stemflow and the output during stormflow are necessary to estimate deep percolation using the chloride mass balance method in forest catchments.
