Learning how to make use of the rain falling on your roof is one of the central tenets of permaculture. No matter how well you plan out your landscape design, however, you´ll never be able to catch all of the water that falls on your site for a pond or for a cistern. And even if you build a massive pond or cistern, the best way to hold water on your site is through developing the conditions to hold water in the soil. Whereas a good-sized cistern may be able to hold 20,000 gallons of water, you can easily store hundreds of thousands of gallons of water in the actual land itself.
A general principle to follow when it comes to managing the water that falls onto your site is “slow it, spread it and sink it.” Water will follow the path of least resistance, and especially if you live on a sloped site, water will tend to form rivets and cause erosion as it rushes down your land carrying away the precious topsoil that you´ll need to grow your crops.
Swales are on-contour ditches that are dug across your site with the purpose of stopping the flowing of water and having the water slowly filter into the land instead of rushing over it. On contour simply means “level”. As the rain water hits the swale, it will accumulate and slowly sink into the land. On a piece of land without swales or other earthworks to encourage water infiltration, the land will begin to dry out a day or two after a good rain. If, however, you have developed a series of swales, the ground soil will remain humid for more time because of the extra infiltration of the water provided by the swales.
How to Find the Contour of the Land
Finding the contour of the land doesn´t require having specialized laser levels or complex GPS-oriented devices. Throughout permaculture circles, the “A-Frame” Level is by far the most widely known and widely used tool to help people find the level of the land. While an A-Frame level is certainly simple to build and easy to use, it is most appropriate for small jobs. Since the legs of an A-Frame level will only allow you to advance 1-2 meters with each measurement, this inevitably poses a problem for trying to map out the contour across a several acre hillside.
Additionally, the A-Frame level doesn’t allow the user to corroborate their findings by taking long distance measurements to make sure that their readings were correct. Finally, the A-Frame level also doesn’t allow you to determine the exact difference in height between one part of the land and the other as it will only give you an estimation of how sloped a certain piece of land is.
The best way to find the contour of your land is through the use of a Bunyip Water Level. This simple “appropriate technology” tool can be built for about a dollar and will last you a lifetime. This simple tool will quickly and efficiently help you to find the contour of your land while also allowing you to measure long distances. A Bunyip water level can be built to measure distances as little as 1 meter apart and as far as 100 meters apart. When built correctly, it also allows the user to determine the exact measurements of slope which will be helpful when determining the movement of water around your landscape.
How to Build a Bunyip Water Level
To build a Bunyip water level, you´ll need two pieces of 1×1´s or 2×2´s about four feet high. Starting a couple of inches from the top, mark every inch (or centimeter) on the post until it resembles a long yard stick. The number “1” should begin at the top. Cut a piece of clear plastic hose about 25 feet long (or the length that you want) and connect each end to the 1×1´s or 2×2´s with duct tape or string.
The length of the clear plastic tubing will be determined by how big a job of marking contour you are undertaking. While a 100 meter piece of tubing will allow you measure contour over very large distances, it can also be used to measure only 1 meter away. Of course, the more tubing that exists between your two poles, the harder it will be to effectively move your posts from one spot to the next.
The Bunyip water level works on the principle that water will always find its way to level. To use this water level, you will need to fill the plastic hose with water through suctioning it through the hose. Make sure that no air bubbles remain within the clear transparent hose as these could throw off your readings.
Now stand the water level up on level ground. If you are on completely level ground, the readings on both posts will be exactly the same. If one of the posts reads 18 and the other 16, then that means that one of the posts is two inches higher than the other one. To find the contour of the land, two people take hold of each of the posts. One person moves his or her post of the water level until they have the same reading. You then place a post or marker at each reading so that you´ll know where contour runs.
Other Possible Uses for a Bunyip Water Level
The Bunyip water level is a great tool that will help you find the contour on your land. While this can certainly help you in your effort to build a series of swales across your landscape, the contour readings can also be used to plant hedges, tree lines, or other forms of perennial or even annual vegetation.
The Bunyip water level can also be used to help you determine slope. A simple Bunyip water level can help you slope the land away from the foundation of your home to make sure that you won´t be accumulating water near your home. It can also be used to determine the adequate slope for moving gray water from your bathroom or kitchen sink towards a gray water pond or wetland.
The versatility that is inherent in the Bunyip water level makes it a great instrument that every permaculture farmer should have on site.