Current trends in hydrogeology seek to enlist sedimentary concepts in the interpretation of permeability structures. However, depositional models tend to account insufficiently for heterogeneities caused by complex controls on sediment preservation. Conversely, geostatistical methods empirically describe both random and structured attributes. This paper presents comparative indicator semivariograms for proximal, medial, and distal alluvial fan settings in Santa Clara Valley, California. Hydrostratigraphic structures revealed by a binary textural indicator are consistent within each setting yet differ from one setting to another. In the bedrock-bounded proximal setting, buried channel deposits exhibit a small nugget effect and a zonal anisotropy with correlation ranges up to 900 m. In the distal setting, deposits display relatively weak hydrostratigraphic correlation with a relative nugget effect of >50% and a correlation range of 80 m. In the medial setting, the correlation range is similar to the proximal area but with a large nugget effect similar to the distal area. ¿ American Geophysical Union 1995