Water resources for sports turf: passing the Environmental MOT
By Dr Jerry Knox
Changes in the way the Environment Agency assess time-limited licenses will impact on all sports facilities dependant on direct abstraction for irrigation. It seems inevitable that golf courses, race courses and stadia will be required to collect additional data to justify their levels of abstraction. Dr. Jerry Knox from Cranfield University describes the importance of irrigation for sports-turf, the proposed tests for licence renewal and how one might prepare for an 'Environmental MOT'.
Is sports turf irrigation necessary?
The public have often questioned whether sports-turf irrigation can be justified given the increasing pressure on water resources, rising demands and longer-term threat of climate change. The current drought in the south east has highlighted the limitations (and risks) associated with relying on mains water for sports turf irrigation, but it represents only the tip of a growing conflict between so-called 'essential' (i.e. domestic) and non-essential (i.e. sports-turf) use.
So is irrigation really necessary, particularly under conditions of increasing water scarcity, or is it just a luxury use by turf managers to improve aesthetics. The answer of course, is that irrigation is an essential tool in the maintenance and management of all modern sports-turf surfaces. It serves to control growth and quality, to maximise playability and deal with the vagaries of UK weather. For golf, irrigation also helps alleviate compaction, maximise aeration and control drainage. In other sports, such as horse racing, whilst the objectives are different, the purpose is equally important, serving to promote sward growth and helping to soften compacted racing surfaces, a common cause of track related injury. It is apparent that much PR is still required to reinforce the importance and value of water for sports-turf.
How much water does sports-turf use?
Golf course irrigation is a very visible activity and one that can be difficult to justify when hose-pipe bans and restrictions are in force. However, the total volumes of water used in golf and sports-turf in general are very small. A sense of perspective is required (see Table 1).
Table 1. Total number of abstraction licences, total licensed and abstracted volumes for sports turf (golf courses and race courses) compared against agriculture. Data relate to 2003.
|Sector||Total number of abstraction licences||Total licensed volume (m3)||Total abstracted volume (m3)|
|(a) golf courses||840||10200000||4320000|
|(b) race courses||35||854000||521000|
The data illustrates that compared to agriculture, which itself accounts for only 1% of total water use, sports turf irrigation constitutes a very minor abstraction. It is, however, a predominantly consumptive use (turf transpiration is a net loss to the environment), peaking in the driest years and in the driest months, when water resources are scarcest. As with agriculture, it is the consumptive nature of use and timing of demandthat accentuates the water supply-demand imbalance.
In England and Wales, approximately 40% of golf courses have an abstraction licence for irrigation; for racecourses the figure is slightly higher (63%). The remainder either do not irrigate or rely on mains water. The irony is that many sports facilities opted for mains water for irrigation because of its greater reliability, but under drought conditions this source has been shown to be equally susceptible to restriction at short notice. Sports facilities need to think more strategically on how to adapt to changing water availability, and preferably to have more than one source on which to depend. Those currently impacted by drought orders might consider switching to an abstraction licence, but even here the rules of engagement are changing…
Tests for licence renewal
New water regulation requires all abstractions for irrigation above the de minimis threshold (currently defined as 20m3 per day) to have a licence from the Environment Agency (EA). All licenses issued since the Water Act (2003) came into force, and many issued previously, are time-limited. Using both carrot and stick, government policy is to encourage other licence holders to convert to time-limited status. These will be renewed on a roughly 12 year cycle, although some licences may have different durations depending on local catchment conditions. The objective is to bring all licences within each catchment abstraction management strategy (CAMS) into line, by defining a common end date (CED).
The EA have stated that there will be a presumption of renewal for a time-limited licence so long as three tests are satisfied (See Table 2). These constitute an 'Environmental MOT.'
Table 2. Environment Agencytests for abstraction licence renewal.
|1||Continued environmental sustainability||To assess whether the continued abstraction can be sustained without significant impact on water resources, other water users or the environment|
|2||Continued justification of need||To assess whether the abstraction is still required, based on the 'reasonable need ' of the licence holder, and to check that the maximum levels of abstraction are still reasonable|
|3||Efficient use of water||To assess whether the right amount of water is being used in the right place at the right time|
Test 1 will be largely undertaken by the EA through their CAMS process. However, the responsibility for satisfying Tests 2 and 3 will rest with the individual. This will require them to submit a well-structured case for licence renewal, addressing a range of factors that impact on their requirement for irrigation (justifying 'reasonable' need), whilst demonstrating that they are also adopting best management practices to ensure wise (efficient) use of the volumes abstracted.
Demonstrating continued justification of need (Test 2) is likely to require a retrospective analysis of water use, including an evaluation of historical abstractions, the seasonal timing of demand, a comparison of authorised licensed and abstracted quantities, an assessment of the impacts of climatic variation on irrigation demand, and possibly some form of water audit. The EA are well aware of the impacts that climatic variation can have on annual turf irrigation needs, but it is important that abstractors can demonstrate a link between fluctuations in their water abstraction with their licensed volume.
Some golf courses have understandably been concerned that their licensed volume might be adjusted downwards, particularly if their abstractions (as a proportion of licensed volume) in recent years have been small (due for example, to a spate of relatively wet summers). It is critical that these differences can be justified; clearly this is a much easier exercise to undertake if appropriate data have been collected on a regular basis over a sequence of wet and dry years as part of the management regime. Relying on memory or ad hoc information on which to develop a robust case for licence renewal will place a business at risk and is not recommended.
One area where there is scope to improve is data collection, relating to the climatic drivers that influence turf irrigation, namely rainfall and evapotranspiration (ET). Most golf courses record rainfall, but only a few measure ET, because it is complex, requiring the integration of temperature, humidity, solar radiation and wind-speed data. Traditionally this has required a weather station (£1500-£2000) but much cheaper alternatives (£300) such as the ETgage (see Figure 1) are now available that can provide a sufficient degree of accuracy for irrigation management purposes.
Figure 1.An ETgage used for planning irrigation applications on a golf course.
In the UK turf irrigation is supplemental to rainfall, and this balance between rainfall and ET can vary significantly, with impacts on irrigation need. In a 'typical' year irrigation is usually required on sports surfaces between April and September when ET exceeds P, but as Figure 2 shows the pattern of rainfall and ET during a wet year (1998) and very dry year (2003) can be very different.
Figure 2. Monthly rainfall and ET at Silsoe (Bedford) in (a) wet year (1998) and (b) dry year (2003).
Clearly, in the context of justifying 'reasonable' need, sports facilities that are aware of and responding to these climatic drivers, and modifying their irrigation practices accordingly, would certainly demonstrate a high level of irrigation management proficiency.
Most golf courses also keep regular records of the total volume of water applied through a season, but only a small proportion actually record the timing and volume applied on each part of the course. If this information were collected, it could be usefully related back to the volume pumped at the point of abstraction. From this it would be possible to compare metered water abstractions with the estimated volumes of water applied to each part of a course Any differences could then be investigated to improve efficiency. This process, known as water auditing has beenwidely promoted as a tool for combining information on climate, irrigated areas and volumes applied to assess 'reasonable' need. The key to water auditing, however, is to keep it simple.
Finally, an inter-related issue that turf managers need to consider is demonstrating 'efficient use' of water (Test 3). For this, they might consider providing a comprehensive review their operational (agronomic, management and irrigation system equipment) aspects of water management on their site. This can then be used to judge the extent to which the current irrigation practices demonstrate efficient use of water. Attendance at workshops and technical meetings for staff to raise awareness of the key issues would also help add credibility.
The way forward
Given the current restrictions on water use for sports turf in the south east, the prospect of further regulation on irrigation abstraction, government demand for greater environmental protection and climate change; it would be easy to conclude that water resources for sports-turf irrigation are under threat. But there are opportunities to respond and adapt in a positive way. Improving one's understanding of water management, identifying alternate water sources, considering water recycling and water harvesting are all feasible options, and likely to become main-stream as the competition and costs for water inevitably rise. Turf managers can and must rise to the challenge of water management.
Jerry Knox is a Principal Research Fellow in the Institute of Water and Environment at Cranfield University and Honorary Secretary of the UK Irrigation Association.