Which factor explains why the Mississippi River's discharge is much greater than the Nile's despite similar basin sizes?

Which factor explains why the Mississippi River's discharge is much greater than the Nile's despite similar basin sizes?

• A. More rainfall in the Mississippi basin
• B. Longer river length in the Nile basin
• C. Higher evaporation in the Nile basin
• D. Larger downstream dam infrastructure on the Nile

Answer: (A)

Discharge is driven by how much water actually enters the river system as precipitation and becomes runoff, not simply by basin size. The Mississippi basin receives heavy, widespread rainfall year after year, so a large portion of that water turns into runoff that flows into the river, giving it a very high discharge. The Nile basin, while large, is drier in many areas, and much of the rainfall evaporates or is used by the land, so less water becomes runoff to feed the river. In short, more rainfall in the Mississippi basin means more water reaching the river, which explains why its discharge is greater.

Discharge is driven by how much water actually enters the river system as precipitation and becomes runoff, not simply by basin size. The Mississippi basin receives heavy, widespread rainfall year after year, so a large portion of that water turns into runoff that flows into the river, giving it a very high discharge. The Nile basin, while large, is drier in many areas, and much of the rainfall evaporates or is used by the land, so less water becomes runoff to feed the river. In short, more rainfall in the Mississippi basin means more water reaching the river, which explains why its discharge is greater.