This article is a follow up to the original article Restricting drainage outfall from reconstructed football pitches
Rain falls invariably at a greater rate than the infiltration rate of the grassed sports pitch surface yet run-off does not commence until all abstractions (initial retention and storage) are complete. The grass species, height of cut, micro-depressions in the soil surface, the gradient of the pitch, the rate of evaporation and the infiltration capacity of the soil all contribute to the amount of water retained before run-off begins. Secondary surface drainage systems have become vital on heavy clay soils in order to provide continual play during wet winters. Actual water run-off to close spaced slit drains is primarily dependent on what amount of rainfall is withheld after all the abstractions are complete. Furthermore, a study of the local rainfall intensity and distribution over 5 to 10 year return periods brings to light the extent to which drainage provisions are necessary.
Key words: water run-off, water retention and storage, infiltration rate, rainfall intensity, gradient, clay soils.