A rainsplash component analysis to define mechanisms of soil detachment and transportation

Abstract

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 rainsplash, even by individual drops, is not a single process but a combination of several discrete but interacting soil particle detachment and transport mechanisms. Because there are a number of possible rainsplash sub-processes that may operate on soils, some of the terminology used in splash studies is inconsistent. In response, this paper reviews some of the past research on raindrop{soil interactions, as well as incorporating observations by the author, in order to clarify the definitions used to describe soil dispersal mechanisms during drop impact. Five main mechanisms are identified, and defined as (1) aggregate breakdown, (2) cratering, (3) splashing, (4) splash saltation, and (5) splash creep, several of which are illustrated with photographic and video techniques under laboratory splash tests. For rainfall in field conditions, an integrated ‘component approach’ introduces a more expansive and flexible approach to rainsplash on soils than is currently available, by considering this geomorphological process as a suite of discrete but interacting mechanisms, varying with changing rainfall and soil characteristics during storms. Some implications of this concept for erosion studies in splash-prone areas are examined.