Infiltration trenches are subsurface engineered structures filled with permeable materials that enhance ground water recharge and reduction of pollutant load in 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).  The above example is an infiltration trench/filter that is covered with grass.  The cross section shows what this might look like underground.
	Drainage swales, channels or pipes can be designed to carry runoff to these BPMs if the natural slope of the land is not conducive to flow in the appropriate direction.
	These BMPs can be hidden by vegetation as in the picture on the left or can have obvious surface features as in the picture on the right.
	One note of caution:  These features require on-going maintenance.