What does 'Runoff' refer to in environmental assessments?

'Runoff' in environmental assessments refers specifically to the movement of water that occurs when precipitation, such as rain or snowmelt, flows over the ground. This water can pick up and transport various pollutants, including sediments, nutrients, chemicals, and debris, as it travels towards nearby waterways, such as rivers, lakes, and oceans. The significance of understanding runoff lies in its potential to impact water quality significantly, as polluted runoff can lead to ecological damage and public health risks.

While deep underground water flow pertains to groundwater movement, this concept is different from surface runoff. The term regarding recycled water for irrigation does not relate to runoff, as it describes a managed process rather than a natural occurrence. Lastly, the absorption of rainwater by soil refers to infiltration, which is a process where water enters the ground, contrasting with runoff that denotes water flowing across the surface. Understanding runoff is crucial for proper environmental management and mitigating the impacts on aquatic ecosystems.