A filter assembly for use in drainage systems to prevent the buildup of eroded materials such as soil, leaves and other debris is disclosed. The assembly includes a unitary frame and a filter media attached to the frame and is adapted to be retained within a component of a drainage sewer such as a catch basin. A porous material filter media such as a woven or non-woven geotextile allows for the flow of water through the filter while retaining debris or soil within the filter. The filter media extends into the basin to provide volume for the retained material without blocking the entire surface of filter.