I can certainly understand your situation. However, are you able to size the diameter of the pipe to that of a WORST-case situation? Suppose you use a 5" pipe. Will it carry the volume of a 25 year flow? If not, where does the excess water go - on TOP of the landscape, above the pipe? If that's OK, then size the pipe for normal flow.
Depending on the details of your project, you need to decide if you're using perforated or solid pipe. Perforated pipe (w/the 'holes' facing down) is used to control rising water; NOT JUST flow. Solid pipe of for flow ONLY.
If you digging or filling, you should line the ditch w/filter fabric; NOT landscape fabric. Use enough fabric to COMPLETELY 'wrap' whatever it is you're putting in the ditch/trench. Don't skimp - It's not worth it. Then, fill w/gravel a bit, then put in the pipe, then cover it w/gravel for a few inches OVER the top of the pipe, then wrap/throw-over the ends of the fabric, then cover w/dirt, then plant grass. Do the Math and based on the # of inches for each 'part' of the project, you can figure out how deep you need to be to begin.