Sprinkler Irrigation: Benefits, Problems and Solutions

Sprinkler irrigation system allows application of water under high pressure with the help of a pump. It releases water similar to rainfall through a small diameter nozzle placed in the pipes. Water is distributed through a system of pipes, sprayed into air and irrigated in most of the soil type due to a wide range of discharge capacity.

Benefits of sprinkler Irrigation 

• Eliminates water conveyance channels, thereby reducing conveyance loss.
• Suitable in all types of soil except heavy clay.
• Water saving up to 30% – 50 %.
• Suitable for irrigation where the plant population per unit area is very high.
• Helps to increase yield.
• Reduces soil compaction.
• Mobility of systems helps system operation easy.
• Suitable for undulating land.
• Saves land as no buns required.
• Soluble fertilizers and chemical use are possible.
• Provides frost protection & helps in alteration of micro climate.
• Reduces labour cost.

Problems associated with sprinkler Irrigation and the solutions

Incorrect pipe sizes 

A common problem in home irrigation installations is the use of incorrect pipe sizes – specifically pipes that are too narrow for the distance required. When water flows through a pipe, a certain amount of pressure is lost due to friction (known as ‘friction loss’). Factors affecting this include the diameter of the pipe, the length of the pipe, and the rate of flow (litres/min), amongst others.

If you currently have pressure related problems due to incorrect pipe sizes, you could try switching to nozzles that use less water (i.e have lower flow rates), which may help increase the pressure in your pipes. Ideally though, pipes should be sized correctly to begin with, so removing old pipes and replacing them with new ones is usually the most appropriate solution.

Wrong Trenching 

Trenching is the most labour intensive part of an irrigation installation, and is therefore often neglected. Many installations are only trenched to the depth of the pop-ups (usually 20-30 centimeters), because this makes it easier – and cheaper – to join the pop-up to the pipe. Unfortunately though, poor trenching can result in pipes being frequently punctured (either by yourself or your gardener), and can lead to frequent maintenance of the system. As a general rule – and unless there are extenuating circumstances such as rock or house foundations – pipes should be trenched to a minimum of 400mm below the surface, and pop-ups joined to the pipe via swing-joint risers or flex-pipe. Not only does this keep the pipes well away from ordinary gardening tools (such as garden forks), but swing-joints allow you to easily adjust the height of the pop-ups in future if the height of the soil changes.

Mixing heads with different precipitation rates and pressure ratings

Understanding precipitation rates is one of the most important aspects to irrigation design, but is often neglected, especially when maintenance on an existing system is conducted. Different sprinklers put down water at different precipitation rates, so mixing sprinklers with differing precipitation rates can lead to overwatering or under-watering of certain areas of your garden.

To avoid these problems it’s important to first understand the precipitation rates of each of your sprinklers, and to only use sprinklers with similarly matched precipitation rates and pressure ratings on the same zone. Doing so allows for efficient, even watering of all areas of your garden.

Pipes crimped by tree roots

One of the most common problems in established gardens is the crimping of pipes by tree roots. Sometimes this is due to pipes that have not been trenched correctly, but for the most part it is because the commonly used low-density (LDPE) pipe and fittings are too weak to handle the pressures of a large tree’s root system. Sometimes – depending on where in the pipe this problem has occurred – crimped pipes can lead to burst pipes, because there is no longer any release of pressure via the sprinklers.

Fortunately repairing a crimped pipe is relatively simple: dig down and find the affected pipe, then cut and replace it. If possible, avoid cutting the offending root – rather divert the new pipe around the root system.

For new installations the use of high-density (HDPE) pipe and fittings can mitigate these problems, so although these materials are more expensive they provide a robust and long-lasting irrigation solution.

Overwatering

Overwatering leads to many problems in gardens, and is a surprisingly common mistake, even for homeowners with automated systems. You will find some homeowners who watered their gardens twice a day, every day, which was a significant waste of water and was hugely damaging to their plants. Plants that have been overwatered are susceptible to fungus and disease, whilst root systems of trees may remain shallow, thereby compromising their stability. To avoid overwatering your garden it’s important to know the required amount of water for your plants per week, and to schedule your system accordingly.

Clogged nozzles and filters 

One of the most important maintenance tasks on an irrigation system is ensuring that the nozzles and filters are clear of dirt and debris. In some cases, especially after a pipe repair, nozzles and filters can become blocked with sand, something that usually occurs at the end of a line. If all the sprinklers in a zone are working fine, but the last one or two are only dribbling water, then the problem might be a clogged filter and dirt in the pipe. To resolve this, remove the head of the nozzle and clean the filter under running water. Then run the system for a few seconds with the nozzle removed. This flushes out any remaining debris in the pipe, and the filter and nozzle can then be replaced.

Micro Sprinklers require constant maintenance 

Micro sprinklers are small emitters that are joined to your pipes via micro tubing. They are useful for difficult to reach places such as potted plants on a patio and are easy to install and use. In most cases they are attached to stakes, which makes them easy to move around and a convenient alternative to other sprinklers. Unfortunately though they are frequently overused, often in places where other sprinklers would be more appropriate. Micros require regular maintenance because the stakes are easily moved (often by dogs), and the tubing can easily be punctured by a gardeners fork. The heads may also pop off, or be accidentally removed, resulting in a wastage of water. Micros do have their place, but if you find they are a constant maintenance headache rather consider a more robust solution, such as pop-ups or risers, or drip irrigation (for vegetable gardens).

For more information on the Sprinkler Irrigation System, contact Mazero Agrifood on 0729777711 and let’s work together.