Publication_Place: Salem, OR Publisher: Oregon Water Resources Dept.
Following the OWRD Drainage Basin map series (see first “cross reference” entry below), OWRD GIS staff used corresponding line work (arcs), where applicable, from a 1:24,000-scale fourth-field hydrologic units theme of the state of Oregon. In cases where there weren’t corresponding lines, the OWRD drainage basin maps were photocopied and enlarged to 24,000-scale and the lines transferred by hand to U.S.G.S. 24,000-scale quadrangle maps. From there they were digitized into the final theme.
Arc were snapped together to form polygons representing the basins and attributed with the OWRD basin name (long & short names) and OWRD basin number.