Traditionally, rainfall-runoff studies are some of the most important methods to help the understanding of the hydrological processes, management of water resources, and potential risks associated with extreme rainfall events (e.g., soil loss, flash-floods, and landslides). This chapter aims to show how an efficient hydrological experimental fieldwork can be designed using practical examples such as plot construction at different spatial and temporal scales, setups, monitoring, and data collection. A correct design of a field experimental monitoring can be an accurate method to give researchers realistic measurements of the variability of runoff response and soil erosion processes, allowing for the production of a large spectrum of data in a medium term period of time. The obtained results show the importance of rainfall-runoff experimental fieldwork and how to manage water resources based on the current status of the understanding of the hydrological field observations and costs associated with runoff-erosion field experimental plots set up.