Reply to comments on the paper “Evaluating and modelling splash detachment capacity based on laboratory experiments” by P.I.A. Kinnell (2019). Catena 183, 104189

Abstract

In this study, we used a new approach to measure and determine the splash detachment based on theories of soil erosion, the large number of articles published on the topic and simulated rainfall experiments. It is a necessity to use and improve new methods to accurately evaluate and quantify the processes of soil erosion. In this experiment, a soil pan with three areas, which consisted of a test area, complementary border area and a splash collector for slots, was used to obtain the ability of soil to undergo splash detachment. In this study, the soil surface was uniform and composed of a smooth slope and depth of thin layer flow that was < 0.43 mm. When raindrop splash occurs on the soil surface covered by a thin layer flow, all the soil materials detached by raindrop splash can only depart the soil surface and penetrate through the thin layer flow into the air and then fall to the soil surface. Splashed soil particles were collected and measured in our experimental setup to represent the amount of detached soil material that instantaneously fell on the test area. This material was quantified in mass per unit area per unit time, which is equal to the sample sediment mass divided by the slot area and the sample time. Thus, it is an expression of the raindrop splash detachment capacity observed in this study. Soil particles occupy all the spaces next to each other, and there is no space for the splashed soil material to move parallel to the soil surface within the soil mass. They may only depart from the soil mass itself. The thin layer flow has a very small depth. The detached soil materials cannot obtain enough space in the water depth to enter and to be maintained within the water depth. They easily penetrate the thin layer flow and enter the air. Once the splashed materials have entered the air, they can quantitatively be observed to represent the splash detachment using the soil pan with three areas in this study. Consequently, the splashed soil materials that were collected using this facility were all soil materials that were detached by the splashing of raindrops during the experiments.