SearchResearch Challenge (12/18/24): What's the most important thing going on here?

 As you might have guessed, 

... during the fortnight break I travelled to Egypt for a too-short two-week trip up and down the Nile by boat.  Starting in Cairo and ending up at the amazing temples at Abu Simbel in the far south, we crossed a lot of river, desert, and history in the process.  

One of the most striking images was of flying over Lake Nasser, a huge reservoir formed by the dam at the ancient city of Aswan, making a lake that's some  222.63 mi (358.28 km) long.  You can barely spot Aswan in the image below at the point where the lake turns into a well-behaved river.  

P/C Google Earth

As we've mentioned before (e..g,  in 2024 or 2016), traveling always causes a host of SRS questions to bubble up to the surface.  On this trip into southern Egypt and seeing the immensity of Lake Nasser raised a bunch of new questions.  

The question that seemed strikingly obvious was understanding the extent to which creating the lake has changed the ecology of the region.  As you know, the Nile used to have an annual flooding cycle each summer, when heavy tropical rains in the highlands of Ethiopia would wash down huge quantities of silt--new soil that would refresh the agricultural fields of Egypt.  

With the dam, that flooding cycle doesn't happen any more, which was a big part of the goal of the dam.  (That is, flood control.) But I couldn't help but wonder--as a consequence of the dam, Lake Nasser now has a gigantic shoreline. By one estimate, it's 7,844 km (4874 miles--but note that "shoreline length" is not a well-defined measure... it varies depending on what measurement tool you're using.  The point is it's really long.

More to the point, that long shoreline now supports a very different kind of plant life than the shore of the Nile supported before the dam.  

Here's a closeup of a piece of the Lake Nasser shore now: 

As you can see, there are now a LOT of trees and bushes that are well-irrigated by the lake's rise and fall with the annual rains.  

This is one effect of creating Lake Nasser, there are probably others.  

For the last SRS Challenge of 2024, I'd like you to do a little bit of analysis and find out: 

1. What has been the most important change in the Lake Nasser region since the lake was created in 1970?  We know the effects of creating the reservoir for Egypt downstream of Aswan, but what about the region upstream (i.e., to the south)?  

There's no single obviously correct answer to this question--and that's part of the point of this Challenge: Not everything comes with a neat, clean, single verifiable answer.  But I'm curious what YOU think are the most striking effects of creating a massive new lake in a part of the world that has never had a lake before.  

When you give your answer, please say what you did to discover the "most important change."  Your approach will determine what kind of answer you find... so be sure to give us an overview of what you did to find your answer.  (Don't just say "there's now more pollen in the air"--that's true, but give us some context about why you think that's important and HOW you found that fact!)  

I'm looking forward to what you discover!  

Keep searching!