Not sure why the media isn't mentioning this in every article about the pool. This happened right after the non-compete contractor coated the pool. I think it was the day after. Trump decided to take his motorcade through it.

President Donald Trump took an unannounced trip to the Lincoln Memorial to see the Reflecting Pool after he had it coated in a color he calls “American flag blue.” He did more than just see it — the president was driven across the new coating before he got out of his SUV to make a statement. The new blue coating will hide the pool's gray stone, a color Trump said was “never good.” The project cost nearly $2 million, he said.

https://www.youtube.com/watch?v=fZDtYhwhD18