Abstract: An apparatus and system for removing debris and contaminants from water passing through a storm drain generally includes a debris trap adapted to fit within a storm drain a porous, filtering element adapted to separate debris from a water flow passing through the storm drain and a frame for directing the water flow into the porous element. The debris trap includes a frame element adapted to substantially prevent bypass of the debris trap, especially during low water flow conditions. The system may further include a debris block adapted to prevent debris from entering a back curb inlet opening of the storm drain. The debris block includes foam end members for adjustably securing and/or sealing the debris block to edges of the drain inlet.