Hint #1: The title of the puzzle is "Don't Go Chasing Waterfalls" (emphasis on the DON'T)
Hint #2: Did you look up the lyrics to the song mentioned in 65-Down?
Hint #3: "Don't go chasin' waterfalls / Please stick to the rivers and the lakes that you're used to"
Hint #4: There are a total of 8 clues with a well-known lake or river in them
Hint #5: Here's a breakdown of the 5 rivers and 3 lakes: 3 in the US, 2 in Africa, 1 in South America, 1 in France, 1 in China
Hint #6: If the first letters of the relevant entries don't make any sense in grid order (top to bottom), perhaps you're looking at it the wrong way?