In my experience, the main problem limiting effective water conservation is lack of knowledge. “
Most people assume water conservation is just installing some sensors and the job is done. In reality, that is just one of several steps.
Most people assume water conservation is just installing some sensors, such as a met station or soil moisture probes, connecting those to the central control programme and the job is done: you are doing water conservation. In reality, that is just one of several steps.
The first step should be a water logistics report:
• How much water does your course actually require? A proper calculation should be carried out with site specific data. If these values are wrong, all the next steps may be rendered useless by a simple lack of sufficient water for irrigation.
• Where and how to source water? Even in an existing course, sources should be checked and compared for cost, quality and constraints (legal and environmental).
• How to store water? In Southern Europe a lake can evaporate as much water as turf. How to design the lakes to minimise losses? How much to have as a reserve? Are tanks more cost effective? Water conservation starts a long time before irrigation.
How to treat water (if required)? If we are trying to minimise water use, minor quality problems can become significant. For example, a minor salt content in the water may cause soil problems if irrigation volumes are limited.
How to manage irrigation? This is the conventional point that everyone talks about.
How much will it all cost? I always recommend that a cost/benefit analysis should be carried out. Following conventional wisdom without actual proof can lead to serious mistakes, both economical and ecological – usually both are associated as, in golf, environmental impacts are mainly caused by resources wastage.
With this report you will be aware of how much you are going to spend on water per square meter of turf and what are the inherent limits of the sources you are using. In the design process of a new course these figures should be supplied both to the architect and the developer, helping to fine tune the design. In an existing course, these figures are the basis to assess investment in system upgrades for water conservation and to estimate return on investment.
The next step is irrigation design. There is plenty of experience on this point, but the relevant features are few: uniformity, a flexible and easily adjusted control system and separation between irrigation areas, such as back to back sprinklers in the greens. The irrigation system should always be integrated with the drainage, lakes and water supply designs in order to save, recover and recycle water.
The drainage system also supplies an important feed-back for water conservation: in the absence of rain it should not discharge. If it does remove excess irrigation water, you are losing not only the water but also money and, potentially, fertilisers and pesticides creating environmental problems.
A further step are sensors and specific knowledge.
A meteorological station will measure evapotranspiration and rainfall. Evapotranspiration is an assessment of how much water was lost by the soil/plant complex, and how much is required to replace it. Some met stations also come with software for turf diseases prediction, helping minimise pesticide use.
Evapotranspiration is a combination of two processes:
- evaporation from the soil surface. This water is not used by turf. The way to minimise this loss is to spread out irrigation cycles, without increasing the applied volume in each cycle so much that water is lost by percolation
- transpiration is what we want – water used by the plant. But, sometimes people confuse objectives. We, in the golf industry, are not in the business of producing and selling turf. What we sell is a good playing surface. Our objective should not be to maximise plant growth and water use, but to minimise it, within the limits required for maintaining adequate vegetative growth and good playing conditions.
Soil moisture sensors measure the actual available water content in the soil. They also provide more important information: the type/strength of water retention in the soil, turf water uptake and stress (how close plants are to the wilting point) and soil moisture salinity. I usually recommend that sensors are installed at 10, 20, 30 and 50 cm depth. The first three sensors measure water content in the soil area where turf extracts water and are used to manage irrigation. The bottom sensor checks for percolation. In the absence of heavy rainfall this sensor must show no change in the soil moisture content, otherwise you are losing water below the reach of the grass roots.
I recommend that the sensors and the control system should not be set to work automatically. A system in autopilot will reduce water use, but results will be limited to just eliminating gross wastage.
For really significant results, sensors provide just part of the required data. There is no substitute for walking the course and to make an informed decision on how much, when and how to irrigate.
Here lies the main difficulty for long term water conservation: it requires not only knowledge and equipment but also self-discipline and perseverance for maintaining and improving procedures day after day, year after year.
Properly planned water conservation measures will deliver:
- Direct results: reductions in resources use (water, fertilisers, pesticides and electricity), environmental impacts and budget.
- Indirect results: better turf quality, less disease (less moisture on surface), less maintenance (reduced mowing frequency and water related problems in the soil) and, an improved environment and budget.
The views expressed in this article are those of the author and not, necessarily, those of The R&A.