theres a large hill on my property that is big enough for me to dig a four foot tall entrance (8 feet of dirt above). and i know to put supports every 3-5 feet. im gonna tunnel thru the side and slope downward then curve off to the side when i think im deep enough. my question is how far down should i and shouldnt i go? i think the sub irrigation water is about 10-17 feet deep (below the surface). any and all help would b appreciated. and anyone who wants to just give bad and/or mean answers just dont even bother. thank u all in advance:)
he's d