Monitoring an installation from the start is vital
It was very sad to inspect a sports pitch complex that was installed with slit drains four years ago only to find that the whole site is a soggy mess. Instead of a firm surface able to shed surface water the soft sponge consistency has simply become wetter and wetter in the current winter conditions.
For a secondary drainage system incorporating slit drains to succeed it is vital that the surface remains firm and the slit drains are not contaminated with the adjacent top soil. Surface water should move readily to the slits and be discharged into drainage system.
To achieve this objective regular sand dressings should be applied to create a sandy layer on the surface – so preventing adjacent clay loam topsoil from capping over the drains. In essence the surface should have a sandy appearance and the pitch should remain firm.