Final answer:
Water from a large rainstorm in Des Moines, Iowa, would enter the Mississippi River watershed, which is known for significant surface runoff and groundwater contributions to river discharge.
Step-by-step explanation:
If a large rainstorm occurred in Des Moines, Iowa, the water would end up in the Mississippi River watershed. Des Moines is located within the Mississippi River Basin, which includes approximately 40% of the United States and comprises smaller drainage basins like the Ohio and Missouri Rivers.
Surface runoff and groundwater seepage contribute to river discharge after heavy rainstorms, and the Mississippi River is one of the largest rivers in North America, known for carrying large volumes of water toward the ocean.