Why is the continental divide important US history

The continental divide is the hydrological boundary of which direction (and ultimately which ocean) water will flow.

Explanation:

Here in the US if you could theoretically stand directly on top of the continental divide and dump a large bucket of water allowing half of the water to flow down one side and the other half to flow down the other side ,then half of the water would eventually drain into the Atlantic ocean (as does all water east of the divide) and the other half would eventually flow into the Pacific ocean(as does all water west of the divide).