Which of the following best explains why reducing surface runoff is considered the most general way to reduce water pollution?

• A. Surface runoff increases the evaporation rate of water, leading to less water available for pollution.
• B. Surface runoff carries pollutants from land into water bodies, so reducing it decreases the amount of contaminants entering aquatic ecosystems.
• C. Surface runoff only affects urban areas, so reducing it has no impact on rural water pollution.
• D. Reducing surface runoff increases groundwater recharge, which directly filters out all pollutants.

Answer: (B)

Verified step by step guidance

1. Understand the concept of surface runoff: Surface runoff occurs when water from precipitation flows over the surface of the land rather than infiltrating into the ground. This water can pick up pollutants such as chemicals, sediments, and waste as it moves toward water bodies like rivers, lakes, and oceans.
2. Analyze the role of surface runoff in water pollution: Surface runoff is a major contributor to water pollution because it carries contaminants from the land into aquatic ecosystems. These pollutants can include fertilizers, pesticides, oil, and other harmful substances.
3. Evaluate the options provided: The first option suggests that surface runoff increases evaporation, which is not directly related to pollution. The third option claims that surface runoff only affects urban areas, which is incorrect because it impacts both urban and rural areas. The fourth option states that reducing surface runoff increases groundwater recharge and filters out all pollutants, which is an oversimplification and not entirely accurate.
4. Focus on the correct explanation: The second option correctly identifies that surface runoff carries pollutants from land into water bodies. By reducing surface runoff, the amount of contaminants entering aquatic ecosystems is decreased, making it the most general way to reduce water pollution.
5. Conclude the reasoning: Reducing surface runoff addresses the root cause of many types of water pollution by limiting the transport of pollutants into water bodies. This makes it a broad and effective strategy for improving water quality.