Hardpack, ledgepack and steep driveways

[Captain Haddock]

I'm finding conflicting advice, info and quotes with no clear understanding .. hopefully someone can clarify for me. I'm asking these questions in relation to an approximately 450ft [fairly steep] driveway that ends at a beach. There is a drainage ditch on one side that is somewhat effective in normal conditions, but struggles with the rains we have had in the Lakes region this summer. So:

1) What is "hardpack"? (what is it comprised of, what binds it together, is it suitable for a steep driveway and will what gets washed down from it during expected erosion affect the beach or lake?)

2) What is ledgepack (similar questions to above)

3) Any recommendations for suppliers of either in the Center Harbor, Moultonborough or surrounding area that can maybe do some grading work and application?

4) What techniques have others used to limit erosion of steep driveways or have you found a better material than those mentioned above to limit erosion?

You may also respond to me at david.grigglestone@gmail.com