Driveways need to be crowned. That is, they need to be higher along the centerline than they are on the edges so that falling rain will head for the ditch and not begin running along in the drive itself. If this happens then it won't be long until you form a rut that will just get bigger and bigger. A flat surfaced, uncrowned drive will soon form pot holes and ruts from water run off.
Turnouts are important, especially on sloping drives, trails or other thoroughfares. Water moving downhill is continually gaining speed, momentum and volume. Have you ever seen concrete lined ditches alongside a sloped section of highway, the ones that have concrete bricks embedded in them? Those bricks are to slow the speed and force of rushing water. By placing turnouts, such as the one shown in the photo, you divert - get rid of - part of the runoff and most of it's damage causing potential. Usually these turnouts are placed at each side of the drive and a "humped up" portion of earth makes sure that the water leaves the drive at that point and does not head down the drive itself.
This turnout on a rocky hillside trail diverts water from a sloping agricultural access off into the drainage at the bottom of a hollow. This turnout to the right has a hump just below on the trail. Note that since there is an earth bank on the left side only a turnout to the right could be made. These turnouts are spaced at about fifty feet apart on this curvy descent to a river bottom field.
Where drainage crosses a trail or drive, a culvert, such as the plastic one shown in the photo, can be installed to stop deepening of the rut that was being made. This drainage crossing the trail was making a rut deep enough to cause problems getting over it.
This bridge was constructed at the owner's shop and is made of pressure treated wood. It was then transported by tractor to the site and set in place. This was much easier than constructing a bridge onsite. It was built strong enough to withstand large, heavy vehicles such as LP gas trucks, tractors and ready mix concrete trucks. Consider what traffic will pass over culverts and bridges that are to be constructed on your drives and accesses.
When buying a tractor you don't have to spend a fortune. Shop around awhile and look for what you want/need before making a decision. A three point hitch, front end loader, detachable backhoe, four wheel drive and extra hydraulics are all things to consider when shopping for your diesel workhorse.
This section of gravel driveway required gravel fill to keep soft material from washing out and forming pot holes. From time to time you may have to add crushed gravel or washed stone to parts of your access drive. Crushed stone will hold together far better than washed river stone/gravel.
A tractor with a front end loader, detachable backhoe and three point hydraulic hitch can be used to build and maintain drives and trails, install culverts, haul earth and gravel and all of the other tasks associated with gravel/dirt accesses.