In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Sounds like your drain field may be to shallow but SD law states the maximum ditch depth to be 4 with a foot of rock for a base, then pipe, more rock, straw, hay, or landscape fabric, then a covering of dirt.
If your drain Field consists of the new gravel-less pipe then the above rules are altered and the manufactures dont usually recommend the pipe be placed any deeper than 2 below the surface to the top of the pipe and that the pipe be installed level.
Was a percolation test done to determine how well water moves in your soil? This is done to determine how many feet of drain field are needed.
As others have stated you may have to add more dirt in the spring. For now Im sorry to say you may have to pump the septic tank periodically and limit water usage.
Where about are you located in this great state? If I can answer any questions for you; Email me and I'll get you my phone #.
Howard Heating & Plumbing Inc.
Howard SD 57349