Yassou, Yusuf
You live in one of the best climates in the world, in my opinion!
That particular Acacia tree is commonly used as a wind break near dunes, apparently, to keep them from being destroyed by wind. If that is not a problem for you then there are many uses for the tree should you decide to remove them.
In an old river bed I would guess that, with cut acacia, you would be able to create wonderful
Hugelkultur beds to help retain the water from what little bit of rain that falls in your area. To help manage water it would be beneficial to create some
berms and swales to direct water flow as well, perhaps from the natural banks of the river and channeling the water down to
hugelkultur beds which would be partially dug out and sunken as to make sure moisture retention is high. Your plant selection looks ideal! I'd add some Moringa trees, and other
medicinal plants to go along with the food production. Add some
Coffee trees in places where other trees will provide good shade...coffee fruit is one of my favorite! "Ice Cream Bean" is another great, beautiful, tree with a food crop. Don't forget about things like Blueberry, Mulberry, Mayhaw, Persimmon, Kiwi vines, Passion Fruit vines, Kukuri Nut (Candle Nut), Tea, and Yaupon holly (Ilex vomitoria, which makes a tea like Yerba matte but is incorrectly said to cause vomiting...it does not.)
There is endless potential!