Wow !! Extremely well done. I like the figure details and the trench is perfect. There were indeed all sort of depths depending local terrain condition, type of soil, etc... Also, a first line trench is different compared with second+ line trenches (Deckungsgraben),and connecting communication trenches (Verbindungsgraben) or forward trenches to the enemy to a MG stand or an observation post. The German instruction book "Die Feldgraue" of December 1916, mentions especially that the trench should be deep and small to provide adequate protection. Soldier could build a step (Schutzenauftritt) if required to look over the trench or to peep through a protective shield. The illustration in the book gives an example of a trench with a depth of approx. 2.5 - 3 meters, but I have seen period photographs of even deeper trenches.
I also have seen a model recently of Andrea-Miniatures
http://www.andrea-miniatures.com/market/AspsProductos/Detalle.asp?IdProductoDetalle=1197
which I will like to make one day !
JS
http://germanuniformsandequipment.co.nr