That said, the flow directions are usually computed so we can calculate upslope contributing areas (i.e. flow accumulation areas) and delineate the drainage networks [see Band (1986, 1989, 1991), Montgomery and Dietrich (1989, 1992) and Peckham (1998) for examples of methods for delineating drainage networks with single flow direction algorithms] along with the basin boundaries and a series of both basin and channel attributes. The topographic wetness and stream power indices are among the most popular of these attributes and unlike the catchment (basin) boundaries and some other attributes, this pair of attributes can be calculated with both the single and multiple flow direction algorithms.