Infiltration trenches and filters are engineered trenches filled with permeable materials that enhance ground water recharge and treatment of storm water.  They “catch” storm water runoff generate on site. They are placed perpendicular to flow at low points on the property (often between the manmade structures and parking lots and a stream or lake).  This is a picture of a sand filter next to a parking lot.  Bricks with sand between them provide a crude filter for large items.  The area beneath is a trench filled with sand and a perforated pipe at the base to encourage infiltration into the subsurface.
	These engineered BMPs do not need to look like an engineered product.  This looks like a sidewalk and easily fits in aesthetically.