Quantitative analysis of the spacing of pools in bedrock and alluvial stream channels in California, Indiana, Virginia, and North Carolina suggest that the tendency for streams to meander in the vertical (or third) dimension, as in the horizontal plane, is a fundamental characteristic of many streams that is independent of material type. Simple linear-regression and correlation models reveal that approximately 70% of the variability of the spacing of pools can be explained by the variability of channel width. Analysis of the spacing of 251 pools in eleven streams, utilizing the Kolmogorov-Smirnov goodness of fit test and one-way analysis of variance suggests that the hypothesis that the data from bedrock and alluvial channels are from the same population cannot be rejected at the 0.05 level of significance.
Morphologic maps and field observations of stream channels incised in sandstone, limestone, metavolcanic rock, and syenite suggest that although these streams have much in common with alluvial stream channels, there exist considerable differences in certain aspects of channel morphology. This results because bedrock control of morphology locally may be more significant than the effects of general processes that tend to produce rhythmic channel forms such as pools and riffles. However, local controls tend to mask rather than destroy the effects of more general processes that produce the third dimension of meandering streams.