A RAINSPLASH COMPONENT ANALYSIS TO DEFINE MECHANISMS OF SOIL DETACHMENT AND TRANSPORTATION

Rainsplash is a term that has been used to describe a wide variety of effects caused by the impact of raindrops on soils. This is because ra insplash, even by individual drops, is not a single process but a comb ination of several discrete but interacting soil particle detachment a nd transport mechanisms. Because there are a number of possible rainsp lash sub-processes that may operate on soils, some of the terminology used in splash studies is inconsistent. In response, this paper review s some of the past research on raindrop-soil interactions, as well as incorporating observations by the author, in order to clarify the defi nitions used to describe soil dispersal mechanisms during drop impact. Five main mechanisms are identified, and defined as (1) aggregate bre akdown, (2) cratering, (3) splashing, (4) splash saltation, and (5) sp lash creep, several of which are illustrated with photographic and vid eo techniques under laboratory splash tests. For rainfall in field con ditions, an integrated 'component approach' introduces a more expansiv e and flexible approach to rainsplash on soils than is currently avail able, by considering this geomorphological process as a suite of discr ete but interacting mechanisms, varying with changing rainfall and soi l characteristics during storms. Some implications of this concept for erosion studies in splash-prone areas are examined.