Originally Posted by stantdm
I don't know if this crossing would get any design help from your local Federal or State farm engineering sections but here is a bit about crossings showing some design criteria for what you are talking about doing. This link covers simple crossings up to multi culvert projects resembling a bridge.

https://www.fs.fed.us/t-d/pubs/pdf/LowWaterCrossings/Lo_pdf/6_Chapter5.pdf

I have some very distant connections with folks who might be able to assist with the guidance / design. Although I have a fair idea of what will and will not work. If installed properly, I think the articulated blocks like below are the best - non permanent option and quickest to build / install. I could construct the grids a hundred yards away from the crossing on dry ground and carry them to the crossing in sections.

[Linked Image from i.imgur.com]