Running water and groundwater are both integral parts of the water cycle. Running water, such as rivers and streams, shapes landscapes through erosion and acts as a resource for energy, industry, and transportation. Groundwater represents the largest accessible freshwater reserve, providing over half of the world's drinking water and a significant portion of its agricultural and industrial needs. It is important to maintain the cleanliness of both surface running water and subsurface groundwater, as water is essential to life and a degraded water supply could create shortages.