גישות כמותיות לתיאור קישוריות נגר במדרונות עם תכסית קרקע מעורבבת

Hillslopes with a mixed land cover are very common in various semiarid regions, including Israel. During rainfall events some types of land cover may generate runoff (e.g. embedded rocks), while other land covers absorb it (e.g. vegetation). The discontinuity in the runoff generation leads to the critical non-linear dependence of the runoff coefficient on the percentage cover. Furthermore, the runoff coefficient (measured on a given plot) decreases sharply with the plot length, also known as the "scale effect". In this article we describe new quantitative approaches to these phenomena and the results of the laboratory rainulator experiments. The suggested quantitative approaches explain both the critical dependence of runoff coefficients on the percentage of cover and the scale effect within the framework of one unified model.