Sampling surface and subsurface particle-size distributions in wadable gravel- and cobble-bed streams for analyses in sediment transport, hydraulics, and streambed monitoring

This document provides guidance for sampling surface and subsurface sediment from wadable gravel-and cobble-bed streams. After a short introduction to streams types and classifications in gravel-bed rivers, the document explains the field and laboratory measurement of particle sizes and the statistical analysis of particle-size distributions. Analysis of particle parameters, including shape, density, and bulk density are also discussed. The document describes the spatial variability of bed-material particle sizes as well as the horizontal and vertical structure of particle deposits. The discussion of sampling procedures and equipment helps the user to make appropriate selections that support the sampling objective. Sample-size estimates may be obtained from empirical data or computed from statistical relationships between sample size and accuracy. The document explains a variety of methods, their usage and prerequisites. A detailed discussion of sampling schemes guides the user to select appropriate spatial sampling patterns necessary to produce representative samples