Biological device that is detained with overflow launder

The utility model discloses a biological device that is detained with overflow launder, including overflow launder, biological detention pond, surface soil, high permeability packing layer, low permeability packing layer, gravel packing and play flow tube, overflow launder and biological detention pond link to each other, and the top facial height of overflow launder in biological detention pond'stop face, and in biological detention pond was placed in surface soil, high permeability packing layer, low permeability packing layer and gravel packing layering from top to bottom, the union coupling that effluents on biological detention pond's lateral wall, just went out the flow tube and is linked together with the gravel packing. The utility model discloses settled simple and easy a filtrations facility before the runoff gets into biological detention pond, this facility can precipitate and filter most suspended particles in the runoff, handles sewage later and gets into the risk that can reduce the jam among t