STORM-proof your farm's driveway to help prevent damage and improve safety.
Recent summer rain storms have carved gullies into many driveways, leaving them scarred and hard to use. These will need proper repairs - with added structures - to avoid a repeat of the damage with the next torrential rains.
Of the thousands of farm driveways I have resurfaced, 90 per cent have been worn out by excess water, not traffic. Farm driveways will last for years once the water problem is solved, because the consistent weight of vehicles will compact them down further.
GET YOURSELF A GRADER BLADE
The best driveways are maintained with a grader blade attached to the three-point linkage of the farm tractor. A grader blade regularly put over your driveway will pay for itself in a few years, because it saves on truckloads of crushed rock washed down the road during heavy rain.
Every farm should have a grader blade because of its multiple uses. I also use mine for digging drains, ploughing contours, preparing ground for tree planting, pipe laying, pushing up logs, heaping up green compost piles, scraping up manure, forming vegetable garden beds, hilling potatoes, knocking down gorse and so on. I have used my unbreakable Berends for 15 years.
CROWN OR CAMBER YOUR DRIVEWAY
Putting a crown on your driveway allows water to roll away into side drains, instead of having water sit in potholes for your car tyres to grind into bigger potholes.
Some driveways on slopes have a camber to have all the water roll over the road as a gentle, broad sheet of water. Unless you have a concrete or bitumen driveway you will need to ensure it's always maintained with a slight crown or camber.
CARVE DRAINS DOWN YOUR DRIVEWAY
This is the all-important conduit for taking volumes of water away before they ooze up over your driveway and start erosion.
Drains should be up to 30cm deep and wide (your angled farm grader blade can do a great job here). Spending time experimenting with angles on your grader is a good idea. Drains will block with sediment, so run your grader blade down on a regular basis and keep them open in readiness for the next rains.
BALLAST OR HEAVY ROCK FOR DRAINS
Sometimes drains on steeper driveways can be eroded badly and will become deep and scarred. To remedy this, hand- place rocks about the size of footballs in the drain to stop further erosion.
Air spaces between the larger rocks allow the water to speed through without gouging the drain deeper.
The 100mm ballast or 200mm surge- pile rocks from your local quarry work well, or simply hand select a few yourself from your own paddock.
Many driveways suffer damage because water run-offs are bypassed through lack of maintenance. Placing water run-offs every 20m to divert water away is probably the most efficient strategy to maintain your driveway.
Culverts or pipes under the road work well, as long as they are not allowed to become blocked with silt and debris. The key is using a culvert with a large diameter. Any pipe under 450mm in diameter will eventually block.
Cheap concrete pipes can be bought from concrete-pipe manufacturers as seconds. When laying your pipe under your driveway make sure it is at the correct depth, and place the spirit level on top to get the right fall. You don't want pools of water lying around breeding mosquitoes.
I always lay heavy pipes with gloves, a front-end loader and a chain to lift them into place, and another sensible person to guide the pipes into place. Always put guide posts at the ends of your culverts to help prevent someone running off the edge and cutting their car tyres.
A speed bump placed at a 10-20 degree angle across your driveway to divert water into the drain is a cheap and effective investment. They don't block, and they slow cars driving up your driveway. I make mine out of clay and have them 10-15cm high.
Finish off your driveway with a topping of crushed rock, which should comprise pebbles between 20-45mm in width, and be well impregnated with fines (5-10mm) and superfines/clay (under 1mm).
Basalt and sandstones make excellent road bases. The superfines nestle in and compact around the larger pebbles once the water cart and compactor are applied.
The crushed rock should be at least 50mm thick so it can bond to the old driveway. It must be watered in with the equivalent of 20mm of rainfall as it is worked, levelled and compacted. Simply driving up and down in your tractor or four-wheel-drive can help compact it down while it's moist.
Some quarries make up a stabilised crushed-rock mix containing up to 12 per cent concrete for about $12 a tonne ex-pit. This compacts hard and lasts where tyres want to spin out as the slope increases, and holds better in heavy rain.
- Kevin Butler owns a small farm in Kilmore, in central Victoria.