Oh no, the water is flowing quickly and not getting absorbed by the dry soil, let us build a giant smooth ramp of completely impermeable material, that will fix things! Now every time it rains people get swept up it, yay!

You know what helps slow down floods, improve soil water absorption, and reduce desertification? Wetlands and lakes. You know why Los Angeles was colonized by the Spanish rather than any other place in its stretch of its very dry coastline? Wetlands and lakes.

The LA river has the same story as its highways and its public transit: elitists destroying anything that does not acknowledge their superiority, actively ignoring if not outright pursuing the suffering of those they believe to be below them.

In this case, real estate developers wanted to replace the low population density wetlands with suburbia to sell houses on the cheap, and when this meant the water had nowhere to go and the city got flooded because they built it wrong, they bullt the concrete chute as a kludge.

Any sane desert city treats water as a precious commodity, not something to flush into the sea at the highest speeds possible. But that would require rebuilding the city right, often in places inhabited by poor people because of the floods urban designers caused.

Los Angeles is not a desert- it’s a Mediterranean climate. It has a wide variety of soil types, both well draining and expansive soils that absorb absorb compacted soils that don’t absorb water.

It used to have many wetlands that absorbed water and sediment. A few areas are left in west LA but the development of the city over the wetlands with poor drainage plans is the issue. Instead of making a network of areas that drain water and create green space engineers decided to just push all the water into one giant channel.