Question
what could be causing this problem and whatcan I do to solve problem

Answer
Good evening Eizabeth:
It would be my guess that the holes have been put in your yard by either the eastern Chipmunk or the thirteen-lined ground squirrel. Either of these critters dig vertical holes about two inches in diameter but then the change direction and go horizontal to the ground line making it seem that they are only a few inches deep. I bet if you tried to fill one of the holes with water it would take much more time than you would anticipate. I also have the eastern chipmunk in my lawn and find them to be fun to watch. They have not created any major damage to my lawn as they do not build up mounds of soil as some critters do. Both will go into hibernation over the winter months.
If you are set on getting rid of them you might try putting a couple of tablespoons of moth crystals in the hole.

What may be digging holes in your yard:
Copy and paste to your browser and hit "GO".
http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/w702whatsdigging.ht...

The Eastern Chipmunk Information:
http://ohioline.osu.edu/hyg-fact/1000/1034.html

Have a good lawn!
Floyd McMahon