Published the 23/10/2018
It is now of prime importance to find solutions that allow water to be used more efficiently and manage its consumption.
The layout of the sprinklers is a key stage in the design of a golf course. The uniformity of application of the irrigation water requires a good level of management. If there should be a significant disparity between the application rates, then it will be necessary to ensure that the irrigation amounts applied to the zones with the greatest deficiency are sufficient to ensure an acceptable level of irrigation, which will also lead to the excess watering of the better irrigated zones. How can we determine the irrigation run time required if the amount of water applied varies within the same irrigated sector? The distance left between the sprinklers when they are laid out, the coherent choice of nozzles, the homogeneity of the trajectory of the streams and the stability of the pressure are the four factors that can assure a good uniformity of application. Once this is established a centralised irrigation management system controlled from a computer will enable you to reduce water consumption. From this standpoint, the major manufacturers of irrigation equipment are developing centralised irrigation management systems specifically for golf courses. These software packages can now determine very accurately the plants’ water requirements. It then allows you to adapt the amount of water to be applied, to manage this application and control consumption. The total interaction between the different components of the irrigation system, i.e. centralised control, pumping station and sprinklers, is necessary if the best results are to be achieved and thus make use of technologies that are becoming more and more sophisticated. So let’s try and see things a little more clearly.
All centralised irrigation control systems have advanced functions for calculating Etp (potential evapotranspiration). Irrigation run times are no longer set on an arbitrary basis, but rather they are based on meteorological information, real or virtual (depending on whether you have a weather station on site or whether you work from a data base) and the application rate of the sprinklers. This software, therefore, allows you to calculate the irrigation run time of each network on a daily basis, resulting in a significant reduction in water consumption from the time this system is installed. In conjunction with a good layout of the sprinklers, this reduction can be spectacular during the first few years. By managing the flow-rates properly you should be able to divide up this application of water by introducing pauses (drying out) between 2 periods of irrigation. This will limit the phenomena of percolation and run-off (and also the leaching of fertilisers). During the stop phase, the available flow-rate is used to operate the other networks, thus reducing the total irrigation time (irrigation window). The integration of all these extra features (type of weather station or pumping station) is, undeniably, a great asset. Therefore, stopping the irrigation system when there is a prolonged period of rain results in a real and immediate saving on water, e.g. 3 mm of rainfall on a surface area of 20 hectares produces a saving of 600 m3 of water.
It is not enough, however, for the system to deliver the optimum quantity of water. It should also be possible to ensure that irrigation, which takes place at night, progresses according to plan. Locating a leak, then isolating the sector concerned, are basic actions that form a part of your approach to reducing water consumption. When choosing your centralised control systems, it is important to monitor the flow-rates, from the pumping station right up to the sprinklers, so as to optimise, in real time, the irrigation cycles. In this case, a software module acts as a course supervisor, permanently monitoring the irrigation system and intelligently deciding on the adjustments required in order to improve its operating efficiency. The combined use of the pumping station and centralised control system allows the user to have a constant exchange of information between the computer and all the decoders or satellites in the field, as well as real-time communication with the pumping station.
The pumping station is in permanent communication with the central PC. It records the data relating to flow-rate and pressure, read by the sensors placed downstream. The software responds intelligently and rapidly to the information received from the station, and modifies and adapts the irrigation taking place. Let’s take a more specific example. In the case of a breakage in the pipeline or a valve staying open, the actual flow-rate of the pumping station will be higher than the theoretical flow-rate projected by the software. If no action is taken, then irrigation continues, leading to the possibility of flooding, sprinklers operating at insufficient pressure and, in all cases, water wastage, less efficient irrigation and potentially costly damage to your golf course. If your pumping station and centralised management system are interacting perfectly, then the system will be able to detect any anomaly in the flow-rate immediately. If this anomaly is only temporary, it will restart and complete the irrigation cycle. If the problem is persistent, it will cancel all irrigations and shut down the pumping station. The fracture of a pipeline, 110 mm in diameter, can lead to the loss of 40,000 litres of water per hour. This is without considering the damage to the golf course.
We should be aware that the advantages of such a system are not simply limited to saving water. It also contributes towards improving irrigation efficiency, by reducing the total run time of the irrigation system. This is the case, for example, when the system detects a slight difference between the actual flow-rate and expected flow-rate. Thus, it does not restrict itself to 150 m3 per hour (for example) if 160 m3/h are available at the station. It will activate the sprinklers required to increase the instantaneous flow-rate to the actual flow-rate of the station. The irrigation window is, therefore, shorter and electricity consumption is reduced. Equally, if there should be a reduction in the capacity of the pumping station (in the event of the pump breaking down), the system will run at too high a pressure, leading to poor uniformity of the irrigation water applied. The system is capable of reducing the required flow-rate (by suspending the operation of the sprinkler networks at the end of the system so as to adapt to the actual capacity of the station). Once full capacity is re-established, the system will restart as many sprinklers as the station allows. In all cases, irrigation efficiency is maintained. With an average water consumption of 36 million m3/year, Golf Courses are placing themselves in the line of sight. Although this level of water consumption is high, up to now it has only created a small number of conflicts of interest. Since last summer, they have, however, become more frequent. In this situation, it is absolutely vital to be able to calculate the amount of water consumed (water meters) and explore the avenues offered by new technology. The ability to react is the most important asset provided by the latest generation of centralised control systems.