SOIL EROSION BY RAINDROP IMPACT (SPECTRUM, HUGONIOT DATA, CRATER BULGE FORMATION)

Raindrop impact has been recognized for years as having an even more important role in soil losses than the total amount of rainfall. Numerous experimental works have been done to determine the amount of soil splash by either single or multiple raindrop impact. Some theories have also been proposed to explain the mechanism of soil erosion by raindrop impact. Unfortunately, the theories proposed have been supported by qualitative description instead of quantitative derivation because the physical parameters involved in the mechanism are not yet clearly understood and defined. Hence, very limited information can be extracted from these proposed theories that is useful in identifying practical methods to prevent soil erosion due to raindrop impact.Based on this theory, some practical suggestions are given as to how to decrease impact erosion by altering selected physical parameters of soil and/or raindrop. Also, some major difficulties which severly hinder the complete understanding of the mechanism are discussed such that guidance is given for further research.The purpose of this present research is to try to understand the fundamental processes of liquid-drop impact from a fluid mechanics point of view and to define all physical parameters of the soil and raindrop involved in the processes. Therefore, a theory is developed to describe the processes qualitatively.