Long overhang and dragging hitch delima--solutions request

I have a dip at the entrance to my MH bay in my house and the new rig's front cap hit when the front tires went into the dip/drain. Raising the front up got me in but I decided to solve the problem by pouring concrete in the dip BUT I still needed water to go through it. Not enough thickness to do 6" pipes so used 2'X12 Styrofoam for the drain and poured the concrete over it plus some rebar to span the hole created. Gasoline eats Styrofoam up very easily once the concrete has cured a couple days.