npaden, dont think i can help you without actually seeing the soil, but i can provide all here a quick summary of what caliche is.
caliche can be either a clay soil or a coarse grained soil (gravel/sand) depending on the occurrence and properties of the soil.
typically in the SW US caliche refers to a gravel, sand, or (in general) alluvial soil cemented by calcium carbonate. there are other types of cementing agents including silica (SiO2), sodium salts, and iron. caliche can be very porous (lets water pass easily), or very tight (holds back water), it depends on the occurence, soil grain size, and degree and type of cementation. in other words, you'd have to characterize your site individually, as caliche soils can exhibit a range of permeabilities and porosities.
edited post.....ok so now i look ewests link.....i think we are on the same page
bottom line is sites have to be characterized individually, as not all caliches are alike.
