Final answer:
Surfaces that do not allow water through, like pavement and rooftops, are known as impermeable. This characteristic prevents water from penetrating the surface, which is significant in urban planning and environmental sciences to prevent flooding.
Step-by-step explanation:
Surfaces like pavement and rooftops, that do not allow water through, are described as impermeable. Impermeability refers to the inability of a material to allow fluids to pass through it. Unlike permeable materials, which have spaces or pores that allow water to filter through, impermeable surfaces prevent water from penetrating, leading to runoff during rainstorms. Impermeable surfaces are crucial in urban planning as they affect drainage and can contribute to flooding if not properly managed.
Understanding impermeability helps us recognize why certain areas are prone to flooding and the importance of designing cities with adequate drainage systems. This knowledge is applicable in geography, urban planning, and environmental sciences. It contrasts with other terms like transparent, which describes a material's ability to transmit light, or opaque, which refers to a material that light cannot pass through at all.