Discussion of “Influence of relative compaction on the hydraulic conductivity of completely decomposed granite in Hong Kong”Appears in Canadian Geotechnical Journal,46(10): 1229–1235.

The completely decomposed granite (CDG) studied by Yin (2009) shows interesting hydraulic properties. The discussers have noted, however, that the paper includes some confusing statements about predictive models and unclear details on the testing procedures for measuring the saturated hydraulic conductivity, ksat. Our comments and questions are expressed in the following order: historical perspective (literature review), basic soil properties, permeability testing, and comparison with predictive models.