By Heatdust
United States 
I have a hump in the middle of my lawn where it used to be flat. The hill is about 1 x 2 meters in area and it has grown gradually for about 5 years. There are no trees in my yard. I'm nervous that this has something to do with my sprinkler system. Any ideas?
8 May, 2011
Previous question
Interesting. Normally one gets hollows in lawned areas where the soil becomes compacted or sinks into old filled in features. I would carefully lift the turf and investigate underneath if I were you.
8 May, 2011