The invention relates to a cover (1) for a drainage channel (2) to be installed in the ground to drain the surface of an area. The cover (1) comprises a substantially planar portion (3) which is constructed so as to cover an opening at the top of the drainage channel (2) and which comprises a projection (5) that extends upward from the planar portion (3). The projection (5) defines an inlet (7) through which the water that runs off from the surface to be drained can enter the drainage channel. In addition, the planar portion (3) defines comprises supplementary apertures (9) to receive water that has percolated down to its lower level.