Sediment control devices (SCDs) include an apertured threshold member and an apertured outflow member, and optionally a filter member between the threshold and outflow members. In some SCDs1 the outflow member has a smaller aperture size than the threshold member, or vice versa. In some SCDs, a filter is placed in front of the threshold member. In some SCDs, there is a substantially hollow sediment control chamber (SCC) between the threshold and outflow members; in others, there is little or no hollow space between the threshold and outflow members. The SCDs can be constructed so that they are resistant to damage by wheeled traffic. The SCDs can be used to control sediment in run-off from a construction site, as drain covers, or as retaining members for lawns or planting areas. A number of SCDs can be joined together to form assemblies which are useful for stabilizing a land mass, for example a gully or river bank.