Question

why is using mississippi river water for drinking water sometimes a problem for new orleans? because it is heavily contaminated by human activities upstream because its too far away from the city and has to be hauled in because the river runs dry many times, especially in the summer

Explanation:

The Mississippi River is used as a source of drinking - water for New Orleans. However, human activities upstream such as industrial and agricultural runoff, sewage disposal, etc. contaminate the water, making it a problem for drinking - water use. The river is not too far from New Orleans and it does not typically run dry in summer to the extent that it affects water supply for the city.

Answer:

because it is heavily contaminated by human activities upstream