Module 6:

6.4 Pitch construction, drainage & carrying capacity

Introduction

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The number of games that can be played on a football pitch so that a suitable and consistent playing experience can be achieved throughout the entire playing season will vary significantly and this is the essence of carrying capacity. This is all very much dependant on the soil type (i.e. rootzone), drainage system and pitch construction, including whether or not any reinforced-hybrid material is incorporated into the pitch.

The local environmental (especially if the pitch is sheltered or exposed) and weather conditions also impact significantly on playability.

The effectiveness and efficiency of maintenance practices and management of usage also contributes a significant amount to how many games are actually played on a pitch.

6.4.1 Pitch construction and drainage

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For this module and course, we will provide a brief overview of the different broad categories of pitch types.

1. Soil based, without any installed drainage system. These will range from heavier clay soil to lighter sandy soils. Playability on this type of pitch is dependent on prevailing weather conditions, with sandier pitches having more flexibility than heavier clay-based pitches.

2. Pipe drain installed to an existing soil-based pitch (This is often referred to as primary drainage). The drainage pipes will only take away water that has reached the depth of the pipe, so a pipe drained pitch offers little if any benefit in practice over a non-pipe-drained pitch.

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3. Sand-gravel slits installed over pipe drains within an existing soil-based pitch. (This is called secondary drainage). This drainage will also typically have a sand-top (of about 25-30mm depth) to maintain the viability of the slits, otherwise as games progress through the playing season they will become capped over with soil from the pitch and their effectiveness can be reduced to almost zero. These can help remove surface water to enable games to be played after a certain amount of rainfall. Sand slits may often be supplemented with smaller sand bands to further improve drainage capability and reduce likelihood of match cancellations.

4. New construction, which will typically be what are called sand carpet, sand profile, or suspended water table pitches. These significantly increase the ability of the pitch to drain and can produce excellent playing surfaces, albeit for a limited number of games until surface coverage and stability starts to degrade.

5. Reinforced-hybrid pitch. This can be either:

• A reinforced pitch with inclusions within the rootzone profile, although this type of pitch might now be classed as legacy pitches due to newer technologies.
• A hybrid stitched pitch, with artificial grass blades forming about 5% of the pitch surface.
• A hybrid laid carpet pitch, which has artificial grass blades embedded into an underlying backing material, again forming about 5% of the pitch surface.
• Lay and play tiles, which are basically small tiles of hybrid carpet with rootzone, that are moved into place typically using a forklift truck.