This metadata file (pbrchseg.met) describes three shape files used. Shape file rivreach.shp contains the upstream and downstream boundaries of seven reaches of the river. Natural features define river-reach boundaries at the confluence of the North and South forks of the Coeur d'Alene (CdA) River, the transition from a gravel- to a sand- bottomed channel, the mouth of the river, and the base of the delta front. Other river-reach boundaries are at midpoints between river-channel drill transects. River-reach boundaries provide end limits for Estimation Units, for which thickness, volume, tonnage, and lead content of Pb-rich sediment were estimated. Shape file segments.shp contains up- and down-valley boundaries of 3 sections of the CdA River valley (upper, middle, and lower), each subdivided into three segments (a, b, and c). We defined these valley sections and segments to facilitate definition and description of along-valley differences in the character of deposits of metal- enriched sediment. These boundaries also define east- and west-end limits of Estimation Units, for which thickness, volume, tonnage, and lead content of Pb-rich sediment were estimated. Shape file Pb1000.shp outlines the area within which samples of surface sediment contain at least 1,000 parts per million (ppm). This outline is the 1,000 ppm Pb contour, which defines the geochemical limit (or cutoff concentration for Pb) of Estimation Units, for which thickness, volume, tonnage, and lead content of Pb-rich floodplain sediment were estimated.