Surface Water Runoff — Passage and Quiz

Surface water runoff occurs when rainwater or melted snow flows over the land instead of soaking into the ground. It is a key part of the water cycle and plays a vital role in replenishing rivers, lakes, and reservoirs.

Runoff is influenced by factors like rainfall intensity, slope of the land, and soil type. For example, heavy rain on steep, paved surfaces creates more runoff than light rain on flat, grassy areas.

While runoff is essential for supplying freshwater, it can also cause problems. Excessive runoff can lead to flooding, soil erosion, and water pollution. As water flows over the land, it picks up pollutants like pesticides, fertilizers, and oil, which can contaminate water bodies.

To manage runoff, solutions like rain gardens, permeable pavements, and retention ponds are used. These methods help slow down runoff, allowing water to soak into the ground and reducing pollution.

Fun fact: In urban areas, up to 55% of rainfall can become runoff due to impermeable surfaces like roads and buildings, compared to just 10% in natural areas.