Draining areas filled with heavy mulch and debris is no problem for the 6 in. Atrium Drain Grate. Leaves, mulch, and debris are trapped at the base, while the raised dome grate continues to drain water through from the top into drain pipe. The specially designed drain grate, also known as a drain cover, is designed to handle moderate flows of stormwater in mulched landscape beds, natural areas, and window wells.