I have done the same thing while I lived on Long Island BUT I used peat moss. During the grass growing season I work in some peat moss three or four times. Just a little at a time hoping it would add to the soil depth, raising the grass plants. Come next season, it looked normal.
Mine was a 6" wide trench from the street valve to my foundation. No matter how careful they were replacing the grass and dirt, it settled causing the difference.
