That part of a storm rainfall that moves quickly to a stream channel. Amit et al. (2002) Ground Water 40, 5 compare quickflow—probably through cracks—with base flow—the slow flow through the porous medium. ‘Quickflow and slowflow refer to relative time constants for characteristic components of observed basin-scale response’ (Schwartz (2007) J. Am. Water Resources Ass. 43, 6).