Final answer:
Storm sewers quickly move runoff water to prevent flooding and decrease erosion. They are different from combined sewer systems, which can overflow and pollute during heavy rains. Storm sewers are an integral part of urban water management and ecosystem protection. The correct option is B.
Step-by-step explanation:
A positive effect of storm sewers is that they quickly move runoff water from one area to another. This function helps to manage the water from rainfall and melting snow, ensuring that it doesn't accumulate on streets, in homes, or other areas where it can cause damage or flooding. By redirecting the water into streams, lakes, or rivers, storm sewers can play a critical role in urban water management and preventing waterlogging.
However, it is crucial to differentiate between combined sewer systems and storm sewers. Combined sewer systems, which carry both sewage and stormwater, may overflow during heavy rain and become a major point source of pollution by discharging untreated sewage into adjacent water bodies. In contrast, storm sewers are designed precisely to handle runoff from precipitation, mitigating potential flooding. They do not treat the water naturally, nor are they equipped with pumping stations in most cases, which are instead typically associated with wastewater treatment facilities.
Environmental benefits of well-managed storm sewer systems also include reducing erosion and controlling the movement of pollutants into water bodies, thereby protecting aquatic habitats and ensuring the health of ecosystems within and around urban areas.
Hence, Option B is correct.