Reclaiming a river bed
In a few places, the Los Angeles River, most of which flows (or trickles at times) in a concrete culvert, has trees growing in it. In certain areas, the water table is too high for the bottom to be concrete and it is native soil.
As we know, nature hates a vacuum, and vegetation has grown in some of these places. Five species of indigenous willow trees, with varying heights, support a variety of wildlife. There is now a movement to enhance any space on the river that could be considered an urban park where people could get a glimpse of nature in a profoundly densely-packed city. There’s also an urban tree planting program -- My daughter Lill knows where fig trees she can reach grow and grazes on her walks.