Technical Note 2: Investigating Golf Course Drainage Systems

Understanding Existing Drainage Before Installing More

Standing water across a parkland fairway under trees after rain, leaves floating on the surface

Introduction

Technical Note 1 explained that many winter playability problems occur because water cannot reach existing drains, rather than because additional drainage is required.

Before installing new drainage, clubs should first understand how their existing drainage system works and whether it is functioning properly.

In many cases, simple investigation can identify the cause of problems and avoid unnecessary or ineffective drainage works, wasting money and damaging the golf course.

Key points for golf clubs

Most golf courses already contain extensive drainage systems

Water often doesn’t reach drains because of compaction or surface sealing

Drainage systems can fail due to blocked outlets or poor gradients

Investigating drainage is usually straightforward and low cost

Good investigation helps target the right solution

1. Locate existing drains

Drainage systems have often been installed over many years without accurate records.

The location of drains is often uncertain
Pipe sizes and depths may vary
Access chambers can be grown over
Trees may interfere with older drains
Older systems may not follow consistent patterns

Clubs should try to locate existing drains before considering new work, which may include:

Drone surveys and aerial photographs
Researching old maps if available
Probing with a steel rod to locate gravel trenches
CCTV survey of larger pipes
Dye testing to test pipe viability and direction
Digging trial pits to confirm pipe location

Even a basic understanding of where drains are located can be extremely useful.

Three photos: a greenkeeper digging by hand to expose a gravel drain trench, a mini excavator opening a trench on a fairway, and a close-up of a gravel drain backfill with a yellow perforated pipe

2. Check drain outfalls

A common cause of drainage failure is not the drains themselves, but the outfall.

If water cannot leave the system, the drains will not function.

Clubs should check:

Pipe outlets into ditches or streams
Culverts and downstream connections
Whether outlets are submerged during wet periods

Outfalls should be:

Clearly visible
Free from blockage
Discharging freely after rainfall

This is a simple but often overlooked step.

A drain outfall pipe discharging into a stream, partially submerged and marked with an arrow

3. Use trial pits to understand the system

Trial pits are one of the most effective ways of understanding a drainage system.

A small excavation can reveal:

The presence and condition of pipes
The type and depth of backfill
Whether gravel is clean or sealed
The surrounding soil profile

Trial pits can also indicate whether water is reaching the drain, sometimes by dye testing.

They are usually quick to carry out and can provide valuable information at relatively low cost.

4. Identify areas of compaction

Even a well-designed drainage system will not function if water cannot move through the soil.

Common causes of compaction include:

Repeated machinery traffic, particularly in winter
Concentrated winter play routes
Wear around greens, tees and paths

Compacted or sealed surfaces prevent water from infiltrating, meaning that drains receive little or no flow. In many cases, deep aeration or changes to traffic patterns may be more effective than installing additional drainage.

5. Understand surface water movement

Before installing new drainage, it is important to understand how water moves across the course.

Clubs should consider:

Where water enters an area
How it flows during heavy rainfall
Where it collects or ponds

In some cases, simple measures such as interceptor drains or minor surface regrading can be more effective than installing additional pipes.

In flat areas where gradients are unclear, a level survey is often essential when works are being planned.

A contour survey plan of an 8th fairway and green showing ponding areas shaded blue and a proposed new 250mm outlet pipe

Final thoughts

Many golf courses already contain more drainage than is commonly realised.

Taking time to investigate how existing systems function will usually lead to better decisions and more effective use of resources.

Installing additional drainage without this understanding can be costly and may not resolve the underlying problem, while wasting money and potentially damaging the course.

Technical Note 3 will address managing traffic and compaction in wet conditions.