In discussion with Stella Rixon, Senior Agronomic Consultant

The challenge facing sports clubs isn’t simply that there isn’t enough water. Increasingly, it is about whether venues understand where their water comes from, how it moves around the site, and how effectively it can be captured, treated, stored, reused and retained.

Across the UK, clubs are facing a more unpredictable water environment. Longer periods of drought are being followed by intense rainfall events, water can be scarce when playing surfaces need it most yet arrive in volumes that sites aren’t equipped to capture.

At the same time, large sports venues can have multiple potential sources of non-potable water, from harvested rainfall to appropriately treated greywater. The opportunity is to consider these sources as part of a single, integrated water-management strategy rather than treating them as separate systems.

Rainwater harvesting is part of a wider water-management system

Rainwater harvesting is sometimes seen primarily as a storage solution. In reality, it should form part of a much wider strategy. Before designing a system, venues need to understand their water balance including catchment areas, rainfall patterns, run-off, water quality, storage capacity, alternative sources such as treated greywater, treatment requirements, overflow and drainage, infiltration and ground conditions, irrigation integration, and ongoing monitoring.

The objective isn’t simply to collect as much water as possible. It’s to create a system that captures water efficiently, treats it where required, stores it safely and makes it available when the playing surface needs it.

Understanding the water balance

A venue may receive significant annual rainfall but still experience shortages, because rainfall and irrigation demand don’t necessarily occur at the same time. Heavy rainfall may arrive in winter, when irrigation demand is low, while prolonged dry periods occur during the peak playing season. Short, intense storms can also overwhelm drainage, sending water off-site rather than into storage.

Annual rainfall figures alone don’t tell the whole story. The more important question is how much of the water available to a venue can be captured, stored, treated and made available when the playing surface actually needs it. This requires understanding the site’s catchment, drainage infrastructure, storage capacity, rainfall patterns, alternative sources and operational demand together.

How much water does a sports venue actually need?

This is deceptively simple to ask and hard to answer generically. Storage needs to reflect the size and type of playing surface, irrigation strategy, local climate, rainfall patterns and the length of dry period a venue wants to be able to bridge, it shouldn’t be read off a rule of thumb.

Simple calculations do, however, show the scale involved. For a full-size 105 × 68m football pitch (7,140m²), 1mm of irrigation represents approximately 7,140 litres. A 3mm application requires around 21,400 litres (21.4m³); 6mm around 42,800 litres (42.8m³).  Some designs work to a larger footprint including the pitch surrounds – one current example assumes a 113 × 74m irrigated area, needing roughly 50,000 litres (50m³) for a single 6mm application.  This illustrates why storage needs to be considered alongside irrigation design: a club maintaining a pitch through an extended dry spell may need far more than a tank capable of supplying one irrigation cycle.

Golf is more complex, since a course can involve greens, tees, approaches and fairways, each with different requirements. UK government guidance offers a useful framework: area (ha) × irrigation depth (mm) × 10 = m³. So 1mm applied over one hectare equals 10,000 litres (10m³). A course irrigating 4 hectares of greens, tees and surrounds would need around 40,000 litres (40m³) per 1mm, rising to 120,000 litres (120m³) at 3mm and 400,000 litres (400m³) at 10mm. Seen this way, a 500m³ reservoir doesn’t look large against actual demand. It’s a clear sign that large-scale water resilience is fundamentally a masterplanning and infrastructure question, not simply an irrigation one.

This is why we’d avoid stating that any surface simply “needs” a fixed application depth. The real requirement is driven by evapotranspiration, soil moisture, rooting depth, weather and surface condition at the time. The right question isn’t “how big should our tank be?” but “how much water do we need, when will we need it, and how long does our stored supply need to last?” Bridging a two-week dry period is a very different design brief from simply buffering between rainfall events.

Designing around the playing surface

Water management can’t be separated from the performance of the playing surface. A football stadium, golf course, racecourse, tennis facility and community site will all have different requirements and even within one venue, different surfaces vary. Rootzone composition, infiltration, drainage, grass species, rooting depth, soil moisture, evapotranspiration and maintenance practices all shape how much water a surface needs and how effectively it uses what’s available.

This is why water management should be designed alongside the playing surface, not as a standalone infrastructure project. A highly efficient harvesting system has limited value if water can’t be delivered to where it’s needed, and improving irrigation efficiency alone won’t help if rainfall is being lost through inefficient drainage or insufficient storage.

From capture to reuse

A resilient venue needs to think of water as a resource moving through the whole site, and ask whether water used for one purpose could have a second life elsewhere.

Capture → Treat → Store → Retain → Reuse → Monitor

Rainwater harvesting is one part of this; venues should also consider whether greywater or other alternative sources could reduce demand on potable supplies. A facilities/clubs showers’ washrooms and other facilities can represent significant water use – treated greywater could potentially be reused for irrigation or toilet flushing, subject to the relevant regulatory and water-quality requirements. Rainwater can meanwhile be collected from roofs, stands and other catchment areas for future irrigation demand.

Rather than starting with a single figure – “we need a 100,000-litre tank” – the more useful starting point is the water balance of the whole venue. Think about:

  • Demand – irrigation, maintenance, washrooms, showers, other operational use.
  • Sources – rainfall, roof runoff, surface water, groundwater, treated greywater, mains backup.
  • infrastructure – collection, treatment, storage, irrigation, drainage, SuDS.
  • Management – soil moisture monitoring, weather forecasting, irrigation scheduling, water-quality monitoring, demand forecasting.

In practice this could involve harvesting rainwater from roofs and hardstanding, collecting and treating suitable greywater, directing drainage flows towards storage rather than discharge, increasing reservoir capacity, improving soil and rootzone water retention, integrating alternative sources into irrigation systems, and monitoring water quality, availability and consumption. Assessing what combination of sources, storage, treatment, infrastructure and management will keep the venue resilient through its most challenging periods.

Connecting water management with SuDS, and designing for extremes

An integrated approach also creates opportunities to connect water management with wider sustainable drainage systems (SuDS) and environmental engineering.  It’s about designing drainage infrastructure that reduces surface water run-off while supporting infiltration, attenuation, storage and reuse. Rather than treating rainfall as a problem to be removed from site, the objective becomes understanding whether it can be captured and used.

Climate change makes this more urgent. Venues need to prepare not just for a dry summer, but for both extremes of the water cycle, drought followed by intense rainfall.

Questions to understand are:

  • Where will our water come from?
  • Where does rainfall currently go?
  • How much can we capture?
  • Could alternative sources reduce reliance on potable supplies?
  • How long can existing storage sustain the surface during a dry period?
  • What happens when heavy rainfall follows drought?

These questions matter for new facilities at the design stage, and equally for existing venues reviewing their infrastructure. The first step isn’t necessarily a new tank, reservoir or treatment system, it’s understanding the site, its water balance, its playing surfaces and its future requirements.

 

A joined-up approach to water management

At STRI, our sports surface specialists work alongside environmental and water-management expertise across the wider Group including The Environmental Protection Group and Carrick Construction, spanning surface design, irrigation, drainage engineering, environmental, SuDS and climate adaptation. This lets us look beyond individual components to how a venue’s whole water system works together, from playing surface and irrigation through to drainage, storage, treatment and site infrastructure.

For facilities considering rainwater harvesting, greywater reuse or a wider water strategy, the starting point shouldn’t be a tank or reservoir. it should be an understanding of the site, its water balance, its available resources, and how those resources can be managed as one integrated system.

Water resilience isn’t simply about using less water. It’s about understanding every available source, capturing more of what we receive, treating and retaining it where appropriate, and applying it intelligently. As the climate becomes less predictable, the venues that manage their water strategically will be best placed to maintain high-quality, sustainable playing surfaces for years to come.

If your facility is reviewing its water management strategy, exploring rainwater harvesting or greywater reuse, or looking to improve its long-term resilience, STRI can help you understand the opportunities and develop a practical, site-specific approach.