A sediment capping system is adapted to create, and distribute, a homogenized mixture of capping material. Where distributing the capping material, the system is configured to militate against the capping material forming clumps of a size and weight that would disturb the sediment on a bottom of a body of water. This in turn militates against the sediment being disturbed, and a disturbing of pollutants and toxins into the water surrounding the sediment. The sediment capping system militates against the clumping of capping material through a vibrating spreader and baffle system, producing a sediment cap with a more consistent depth that will minimally disturb the sediment on the floor of the body of water where the sediment cap is being deposited.