One of the great benefits of running a school project which involves growing plants, using garden tools and creating systems, such as building a simple irrigation system, is that it educates on so many levels. In one small project, biology, engineering, and organisational skills are all brought into play. Teaching students how to put together a simple irrigation system has many potential benefits, especially given the demand on water supplies.
There are a number of ways in which plants can be irrigated, but by the far the best way of irrigating plants is by sprinkler system. Sprinkler systems are controllable and cost-effective. They make the best use of water supply, and limit the amount of water wasted. For a school project, one of the simplest methods of creating a water sprinkler system is taking a garden hose and piercing holes in it. Simply by turning on the water tap, water will be sprayed onto the plants or crop. Piercing the hose at predetermined intervals will ensure a good coverage.
The difficulty with using a simple hose method is that it can be difficult to control where the water ends up. Piercing a hole in the hose does not allow much in the way of direction. Also, unless multiple holes are pierced, it can mean that each plant only gets one small stream of water. If not placed correctly, or if the crops are not sufficiently spaced, it is possible that some plants may not receive the water they need.
A better option is to fit riser pipes in the hose, or, alternatively, build smaller sections of hose and join them with small T-connectors to which riser pipes can be added. This offers the benefit that the sprinkler systems act more like natural rainfall. With riser pipes, the water is sprayed over a larger area, ensuring better coverage. In addition, the sprinkler heads can be adjusted so that there is not too much overlap in the system. Another advantage of this system is that it is simple enough for young students to build, but it also means that it is possible to block off the sprinkler heads which are not in use -- a valuable lesson in water conservation.
To feed the water through into the sprinkler heads, water needs to be sent under pressure into the main pipe. One simple method, which students can easily build, is simply having a small tank, which is raised on a platform. Water flows down into the pipe and up into the riser pipes. For something a bit more ambitious, a small electric pump can be used, but this require careful monitoring by supervising teachers.