The article discusses how rain and runoff can cause soil erosion. It explains how raindrops can detach soil, and how erosion can be studied in the lab. The Universal Soil Loss Equation helps quantify erosion from storms. Researchers at Drexel University are testing an erosion control system using rainfall simulations. They are also studying the effectiveness of natural and geosynthetic erosion control systems. The goal is to better understand and prevent soil erosion.