Theoretical and practical aspects of the construction of a new apparatus for intercepting sedimentary particulate fluxes are described. Twenty‐five square boxes, brim‐filled with artificial sediment, were positioned on a table about 1 m above the bottom of a lake so that, collectively, they presented a continuous (0.7 m2) interface with the water which was intended to generate boundary‐layer characteristics modeling those of natural lacustrine sediments. Results indicate that the box traps nevertheless seriously underestimated the net sedimentary flux.