Riverbed permeabilities: information from pooled data

Numerical values of hydraulic conductivities of river channel-lining materials are assembled from published and unpublished sources. These are found to cover a range from below 1.0 x 10(-9) to above 1.0 x 10(-2) m sec-1 and to be concentrated in the region 1.0 x 10(-7) to 1.0 x 10(-3) m sec-1. Variability within a site can be large. Assessment of the values in relation to sediment, scale, and method of determination presents a complex picture, and generalization is not straightforward. Hydraulic conductivity determinations from numerical modeling, which tends to be associated with averaging at larger spatial scales, are associated with a more conservative range of values than those derived from field and laboratory analyses. The sample of determinations provides a guideline basis of representative values for hydrological and hydrogeological assessment where specific investigation is not possible.