How do urban surfaces typically contribute to flooding?

Urban surfaces contribute to flooding primarily because they are designed and constructed in ways that modify natural water flow. Impervious materials, such as asphalt and concrete, cover most urban areas, preventing water from being absorbed into the ground. Consequently, when rain falls in urban settings, the water cannot infiltrate the soil. Instead, it runs off quickly across these hard surfaces, funneling into drainage systems, streets, and ultimately to natural water bodies like rivers and streams.

This rapid diversion of water can overwhelm existing drainage systems, especially during heavy rains, leading to flash flooding and localized flooding events in urban areas. Urban infrastructure such as gutters, storm drains, and culverts are often designed to handle a certain amount of water flow, but when precipitation exceeds this capacity, it exacerbates flooding conditions.

In contrast, other options do not accurately reflect the contribution of urban surfaces to flooding. For example, urban surfaces typically do not absorb water quickly, retain water longer, or disperse water evenly; rather, they expedite runoff into drainage systems, which is the key reason why option C accurately describes how urban areas contribute to flooding.