PART ONE of this in-depth feature explores practical approaches to moisture management and how it has evolved into a critical performance variable rather than simply a routine maintenance task.

Across all areas of sports turf, water management has become a central part of surface performance.

Changing weather patterns, increased scrutiny on water use and rising input costs mean turf managers are expected to deliver consistent playing conditions using less water and with fewer opportunities for error.

Climate variability is the real challenge

Although long-term data suggests the UK is getting wetter overall, day-to-day turf management tells a different story. Prolonged dry periods in 2010–12, 2018–19 and 2022 were followed by record heat, then periods of exceptional rainfall during 2023 and 2024.

For sports turf professionals, this means rapidly shifting between drought stress management and excess moisture control. This is particularly challenging on intensively used surfaces where recovery time is limited. Rainfall distribution remains uneven across the country, with eastern and south-eastern regions facing the greatest pressure on water availability.

Water use and increasing scrutiny

Management of turf surfaces sits within a wider conversation about water abstraction and sustainability. National projections indicate that overall abstraction may need to reduce significantly by 2050 to protect catchments and ecological status, particularly in water-stressed regions.

While sports turf is not the largest abstractor, it is highly visible and seasonally intensive. Many facilities still rely on mains potable water for irrigation, making efficiency and justification essential rather than optional.

Irrigation efficiency is the first priority

Improving water efficiency starts with understanding the performance of existing irrigation systems. Poor distribution uniformity remains one of the most common causes of excessive water use across sports turf.

Key areas to assess include:

• Uniformity of application across playing surfaces
• Pressure consistency and sprinkler performance
• Precipitation rates relative to evapotranspiration
• Clear, evidence-based irrigation triggers

Without good uniformity, surfaces may be overwatered to compensate for dry areas, increasing disease pressure, surface instability and operating costs.

Soil hydrophobicity reduces water effectiveness

Hydrophobic soils are a major barrier to efficient irrigation, particularly on sand-based and free-draining profiles common in sports turf. Water-repellent soil particles prevent uniform infiltration, resulting in localised dry areas despite irrigation or rainfall.

The practical consequences include:

• Inconsistent moisture distribution
• Increased hand watering and labour input
• Reduced stress tolerance during dry periods

Managing soil water repellency improves infiltration and lateral movement of water within the profile, allowing irrigation and rainfall to contribute effectively to plant available water. Where hydrophobicity is addressed, irrigation demand can be reduced by up to 80 per cent, with improvements lasting several months - when using residual wetting agent technologies such as Aqua-Zorb® Liquid - depending on conditions and maintenance practices.

Putting water volumes into perspective

Ensuring rainfall and applied water reach the rootzone is a critical aspect of effective water management. If soils are compacted or hydrophobic, surface water runoff and pooling can be inevitable. This reduces plant water availability and leads to wasted resources when applying abstracted water. Use of cultural techniques alongside appropriate wetting agents at the right time can help to move water away from the surface allowing improved wetting of the rootzone.

Practical water management is good turf management

For sports turf professionals, sustainable water management is not about restriction. It is about control. Applying water only when required, ensuring it reaches the rootzone and maximising the value of natural rainfall all contribute directly to surface performance.

Dr Abigail Graceson - Technical Manager,  Agrovista Amenity

Water is, I think, a resource that perhaps we have taken for granted over the years. It is difficult sometimes to think otherwise, especially after five months of near-incessant rainfall and flooding. Cast you mind back though and, less than six months ago, it was a very different story with water storage reservoirs at 50% of capacity and groundwater levels classified as very low.

Over the last two years we have had two completely different weather scenarios;

2024 – A southerly-orientated jet stream that allowed Atlantic, low-pressure systems to dominate the weather picture through the spring, summer and autumn. The result – a very wet and humid year with record annual rainfall levels.

2025 – A northerly-orientated jet stream that pushed Atlantic, low-pressure systems up and over the north of the U.K and allowed high pressure to dominate from early spring right through to the beginning of autumn. The result – one of our driest and warmest spring and summer seasons with minimal rainfall and high ET.

You can see the contrast in the Prodata Reports annual summary below, with data taken from a Davis Weather Station in Thame, Oxfordshire:

In 2024, the location recorded 893.4mm of rain vs. 625.8mm of ET, resulting in an annual surplus of 267.6mm. The soil moisture surplus/deficit summary (SMS/SMD) indicated the soil went into a slight deficit in May 2024, which increased significantly in June 2024.

Contrast this with 2025.

In 2025, the same location recorded 596.2mm of rain vs. 706.9mm of ET, resulting in an annual deficit of -110.7mm. The soil moisture surplus/deficit summary (SMS/SMD) indicated the soil went into significant deficit as early as March 2025 and this continued every month until September.

So, when we are looking at balancing our water reserves, we also need to take into account how much of that water we are losing by a process called evapotranspiration (ET); let’s look at that process:

About evapotranspiration (ET)

ET is the loss of moisture by evaporation from the soil and transpiration from the grass plant. This is then reported by the weather station in terms of mm of moisture lost by the soil and grass plant leaf, usually over an hourly and a 24-hour period.

A weather station doesn’t measure ET, rather it measures the parameters utilised in the equation used to calculate it. This is called the Penman-Monteith equation (FAO-56) and it is shown above.

We can see that in order to calculate ET by the Penman-Monteith equation, we need to measure solar radiation, air temperature, humidity and wind speed, and that’s where a weather station comes in. So far so good.

Penman-Monteith equation (FAO-56) Reproduced courtesy of fao.org.

The Penman-Monteith calculation however over-estimates the loss of moisture from close-mown turf. This is because the calculation assumes a height of 2m, where wind speeds and temperatures are higher than at ground level and humidity can be lower. It also assumes the reference crop is 12cm (120mm) tall, actively growing, well-watered, uniform and dense, with no disease, stress or compaction.

Clearly these assumptions are incorrect, so the net result is an over-estimation of the moisture loss by ET.

For the turf manager, he or she must then decide how much of the moisture loss attributed to ET is replaced by the irrigation system.

Typically, this is 50-60%, but it is dependent on a lot of variables including grass species, cutting height, rootzone type, active root system depth, PGR usage, nutrition and local topography to name but a few. I know turfgrass managers who choose to replace 40% of the calculated moisture loss by ET using their mains irrigation and then rely on hand watering to deal with the hot spots.

Whichever way it is done, using a weather station to measure ET provides a hard and fast record of moisture loss from your site and one that serves to highlight the requirement for irrigation. Without having ET as a reference point, your irrigation strategy is compromised. Even direct soil moisture monitoring should be reliant on knowing how quickly that soil moisture level will decrease due to moisture loss by ET.

As a point of reference, we have measured up to 8mm of moisture lost on a windy, warm July day in the south of England and up to 134mm lost in one month alone (July 2018) at our default location in Thame, Oxfordshire.

When I am asked to justify the expenditure on a weather station and what it gives you, my first answer contains ET. Always.

Mark Hunt  - Weather Analytics, Prodata Weather Systems

Drought resilient turf grasses

Species selection for modern turf management

Periods of prolonged drought are becoming increasingly common across Europe and the UK, placing unprecedented pressure on turf managers in sports, amenity, and landscape settings.

Selecting grass species with inherent drought tolerance is now one of the most effective long term strategies for maintaining turf quality while reducing irrigation demand. This article examines the leading drought resilient turf grasses, compares their performance traits, and outlines practical considerations for integrating them into modern turf systems.

Why drought resilient grasses matter

Drought stress affects turf in several ways:

• Reduced shoot growth and colour loss
• Thinning swards and increased weed ingress
• Soil hydrophobicity and reduced infiltration
• Higher susceptibility to pests and disease

Species selection is the foundation of drought resilient turf. Deep rooting, efficient water use, and heat tolerance are the key physiological traits that determine how well a grass survives extended dry periods.

Essential Q&A guide for water recycling

How does a recycling system lead the way in sustainable water management?
It recycles up to 95% of all wash water and naturally tops itself up with rainwater, making it highly sustainable and reducing reliance on mains supply.

Is there legislation requiring clubs to recycle water?
Yes. The Groundwater Legislation Act 2009 requires all wash water to be contained and either treated, recycled, or correctly disposed of.

What are the benefits during drought?
Because the system reuses on‑site water, clubs can continue washing equipment even when drought restrictions limit mains water use.

How much can a club save on water bills?
A ClearWater system can save over 500,000 litres of mains water annually and helps avoid government fines that can exceed £50,000 for improper wash water handling.

Is the system easy to manage?
Yes. With only two moving parts, it needs just an annual service and simple weekly checks.

How much space is needed, and where can it be installed?
A typical setup uses around 7m x 7m for the washpad and tank. The tank can be placed 30+ metres from the pad, and the pad can be built to any size or shape to suit site needs.

Matthew Mears – Director, ClearWater

... Part Two coming this Thursday!