Documented Growth of the Marsh in the plain of Troy

Historical satellite pictures at Google Earth prove that the marsh in the plain in front of Hisarlik grew larger between 2016 and 2019. 

The photos above are dated in their top left corners.  The first photo is from June, 2016. The second photo is from February, 2019. In the later photo, the marsh has grown a tail at its south end that reaches nearly to the bottom of the photo. This tail still exists in the October, 2020 photo below, which is the latest image available from Google.  The extended portion of the marsh does not occur in any of the earlier images, which go back to 2006. 

I don't have an interpretation of this.  I would expect a marsh that is being drained like this one to shrink rather than grow, but I can't really justify my expectation.  

Perhaps water is undermining the mound. I think the marsh is on top of a buried city, so, I wonder if the land is settling into the ruins below.  But surely marshes expand for reasons other than water and buried ruins.  

It seems certain that agribusiness would be making money on that land if they could. They used to make money from it. All of the historical pictures show planting and harvesting going on in that area, until 2019.  There must be a good reason they are no longer using that land to make money.   

There are no Google images for any years between 2016 and 2019.  Whether the productivity of that land was lost gradually or suddenly we cannot be sure.  The story of how it happened can be known, however, because people involved in agriculture in that area are still alive to be interviewed.  Finding out what happened would be a good topic for a young researcher who speaks Turkish.  

Why would a marsh grow like that?