[asdff]

When white people first came to Los Angeles, they mocked the Californios who built their houses upland, and had to come down to the river to utilize it or collect water. Then it became clear why that was, when nascent Los Angeles was pummeled again and again by flooding. The worst of which in the 1930s resulted in the Army Corps of Engineers intervening and channelizing the river, converting much of it into the cement gutter we know today.

It wasn't just the LA river, but also all the creek beds that fed into it were also channelized or buried under roadways and development:

https://i1.wp.com/www.hiddenhydrology.org/wp-content/uploads...