Question
Hello Kenneth,
I live in Wisconsin, and am already thinking about Spring! I had a
severe problem with my lawn this past summer and am not sure
what happened.

My south-facing front yard started to develop strange dying
patterns. It started with a few small dead patches then led to
many in the front yard. When viewed from the second floor, the
patterns almost looked like little rivers running through the turf.
It seemed to only affect the areas in direct sunlight. We did have
a small ant problem that I took care of with granules. I noticed
birds visiting the areas I put the granules as well. In addition, I
have noticed more and more patches of tall fescue that only
appear in the front as well.

Any ideas? thank you.

Answer
I could be mole tunnels under the ground which you are seeing. Sometimes they can damage turf. Trapping is only real way of control.

It can also be grubs which eat the roots. Finally, due to your description of the sunlight effect, I think it could be chinch bugs. they eat grass in sun mainly. However, they create damage in patches.. not "rivers".

Tall fescue grass is more likely wild onions or quack grass spreading. latter is especially common in early wet springs (do not confuse with crabgrass). Both wild onions and quack grass are perennials and only remedy is to dig out and reseed.