Appendix B—Report of the subcommittee on subsurface flow

Abstract

Because of war programs, no attempt has been made to expand the membership or the activities of this subcommittee during the past year. A statement of research‐needs,to comprehend subsurface stormflow better, was presented at the last Annual Meeting and appears in Part V, Transactions of 1944, pages 743–746.Exchange of correspondence has brought to light a growing interest in the phenomena of dynamic subsurface water‐movements during storm periods. During the year a valuable paper by Parsons [see 1 of “References” at end of report] has emphasized the importance of interpreting the flood hydrographs in terms of “the various elements of basin storage” which he recognizes as outflows from surface, subsurface, and ground‐water storage. Following the general method of Barnes [2], he has presented a graphical recession analysis indicating that storm runoff appears as three approximately straight lines when plotted on semiloganthmic paper—representing the surface, the subsurface, and the ground‐water fractions. This concept is then used in the calculation flood hydrographs from precipitation records. Stafford and Troxell [3] have likewise recognized runoff an being of three types: (a) surface storm‐runoff; (b) subsurface storm‐runoff; and (c) ground‐water seepage, and have associated these throe types with basin characteristics in the San Bernardino and Eastern San Gabriel mountain drainages in southern California.