Abstract: A filter is disclosed formed of a bag having sidewalls of a semi-permeable material. A debris dam is provided at the upper edge of one of the sidewalls and has a generally cylindrical shape formed from a porous material. The filter is intended for use in conjunction with a drainage system and the bag is mounted to be positioned below the catch basin of such system and the debris dam fits within the overflow slot normally provided. When water or another liquid passes through the filter any solid debris which the liquid might have been carrying is removed and trapped in the filter bag.

Abstract: A drainage system for location adjacent a pavement subbase includes a tube of a geotextile fabric supported by a self-sustaining water-porous plastic support. An end of the fabric tube and its encased support are compressively received in the flared open end of an outlet connected to a conventional drainpipe. The outlet includes a plurality of projections which trap the fabric tube between the support and the outlet, so as to securely retain it therein. The outlet also preferably includes a plurality of circular beads over which a corrugated drain tube can be frictionally slipped. Alternatively, the outlet can be configured as a flat union or T-shaped junction joining one or more upstream fabric tube-and-support filters with a downstream outlet constructed from an identical fabric tube and support. The downstream outlet can also be in the form of a union for connecting two or more upstream fabric tube-and-support filters in addition to having means for connecting to a drainpipe or the like.