The present invention relates to an apparatus for maximizing the blockage of fluid borne solid materials from passage through a catch basin into the downstream parts of a fluid flow channel, with minimum impact on the volume and rate of fluid passing through the channel. The apparatus comprises at least one filter sheet secured within the catch basin at a location above and covering a large proportion of the floor of the catch basin, an overflow wall separating the filter area from an unfiltered overflow area, and a diverter for directing incoming trash away from the overflow area and to the filter side of the overflow wall. Although the apparatus covers a large area within the catch basin, the overflow wall, overflow area, and clearance between the filter sheet(s) and the floor provide sufficient space for fluid and excess trash to pass in the event the capacity of the apparatus for holding them is exceeded. Preferably, the apparatus also has a drain-access hole through the filter sheet(s) and a movable hole cover located appropriately to facilitate access to the catch basin drain.