Explain why reducing surface runoff is the most general way to reduce water pollution.

Yes reducing the surface runoff will reduce the water pollution.

Explanation:

During precipitation in the form of rain, a part of it seeps into the ground as Earth' ground water, whereas another part of it moves downhill as runoff. It helps in improving the landscape by erosion and also adds water to rivers and lakes. But at times it may be dangerous due to toxic runoff i.e. the runoff can pick up certain soil contaminants along with it into the near by rivers and lakes. Contaminants like pesticides and fertilizers enter the water bodies leading to water pollution.

Surface runoff refers to the water from snowmelt, rain, and other sources, which flows over the surface of the land, and is a prime constituent of the water cycle. As the movement of runoff takes place, it picks up and carries pollution along with it. This pollution further gets deposited into the water bodies like lakes, ponds, and underground drinking water sources.  

Surface runoff comprises a huge list of non-point pollution sources associated with human activity. It takes place when the water carries undesired components into the environment. Thus, if this runoff is prevented on a major scale, then it possesses the tendency to substantially minimize water pollution.  

the supermassive black hole is in the middle of the galaxy.

this is a good question! i'll do some research and come back when i have the answer!