Thanks for the thread! Mind if I ask a question?

In my story, there's a river that plays a major role in the economy and life of a whole region, but its extremity has recently dried up, as massive amounts of water are used by irrigation grids, cities and factories further inland. So, there used to be a massive delta with a city on one of its edges, but now there's just a marshy area at the tip of the delta that's the furthest from the sea, and the rest has dried up as there's simply not enough water left to reach the sea (it all happens under a warm climate, and I'm using the Colorado river as an IRL example of such a situation.)

How could that dried up delta look? Would it still see vegetation growing due to the water seeping through the ground and the fertile soil formerly carried by the river (like the Nile in Egypt, where people grow food in the soil brought by the seasonal floods)? Would it turn into an arid place due to the loss of water influx? (the region around it is relatively arid to begin with). Would salt marshes appear close to the sea?