Knowing how to find and mark out a contour line is darn useful.
It allows you to build foundations for houses, catch and store water and nutrients in swales or swale pathways, make fantastic walking tracks across steep hillsides and numerous other fantastically functional things.
There are three different ways (high tech and low) to find and mark contour lines.
THE BUNYIP LEVEL (AKA THE WATER LEVEL)
This handy tool consists of two posts and a hose connecting them, so it's free or dirt cheap to make.
On each of the upright timber posts measurements show up to one metre off the ground.
This means you can match the water line against the numbers at both ends of the hose, ensuring you have the same level. We added some yellow food dye into the hose to see the waterline more clearly. To make your own easily at home, watch Brad Lancaster's video and check out his other work ... when it comes to water harvesting he's one of the best. The hose can be varying lengths, this one is approximately 10 metres, which allows you to mark out short or long areas and move around corners or structures.
One thing you do have to watch for is making sure that you hold the post perfectly upright. To help, hold a spirit level against the post to make sure it's vertical (instead of leaning to one side) so you get an accurate reading. This is a minor, yet crucial detail in creating successful contours. We used the bunyip level a lot at our own place for creating swale pathways among our vegetable gardens and they work a treat.
The A-frame consists of three sticks, a length of string and a weight to hold the string down - we've used a big heavy bolt for this particular one. When making your own, the key thing to remember is to make the distance between the legs a desirable length, one or two metres generally works well as it helps you keep track of distance.
See a step-by-step guide to making, calibrating and using an A-frame at https://www.youtube.com/watch?v=gjE-6B13hkQ. The guys on this short film are using nails to join the timber pieces together, but we recommend using screws, bolts or just some strong lashing as nails have a tendency to pop out sooner rather than later.
THE LASER LEVEL
The laser level is the high-tech option which can get fairly pricey, however, you can also hire them by the day. This is good for big jobs as it's quick to mark out large areas with one person, and when you're working with an earth-moving machine, it's easy to check or tweak levels as earth is being moved. It consists of a tripod with a 'computer head' (not the proper term) on top, which projects a laser light to the height of your choice and a long, retractable measuring stick with an electronic reader on it which picks up the laser light coming from the tripod.
All of these contraptions can also be used to create a gradual 'fall' on your site so water is channelled across landscapes, or you might want to create a ramp for wheelbarrows and walking.
If moving water, the recommended fall is 1:400, one metre over 400m (or one centimetre over four metres) as this will move your water slowly over your property, ensuring it still soaks into the soil first before moving to the next area. The really great thing is that when used correctly, the A-frame and bunyip level are just as accurate as the laser level, they simply require a bit more time to do the job.
For more visit, goodlifepermaculture.com.au