C.S.O. stands for combine sewage overflow.This occurs when it rains a tenth of an inch. All the water and the run off goes into the sewers. The fertilizing company can not contain all the extra sewage so it dumps all the sewage in the Bronx river. There for it contaminates the river. Now here are some options that you can take to prevent this:
Rain Barrels- these collect the rain drops that fall from the sky or from roofs of houses.
Green Roofs- these contain flowers which would suck up the rain drops.
Gardens- gardens also suck up the rain drops because of the soil and plants
Permeable Surfaces- these are surfaces that absorb the rain unlike concrete
Green Wall- A green wall would also prevent cso's because the wall would have plants and the plants would absorb the rain fall.