The tree filter system consists of a granite or concrete curb frame with a choice of hardscapes or grating, such as brick, granite, concrete, pervious pavers, or metal/HDPE grating, which surrounds the tree. Stormwater enters the system along a curb opening and flows into a sediment collection sump beneath the curb. Floatable trash, sand, and sediment collect within the sump. Water then flows to the opposite side of the sediment collection sump, over a weir, and onto a three inch thick mulch layer surrounding the tree. Smaller sediment particles adhere to the mulch layer. Water moves downward through an engineered soil media and through a layer of double washed stone within a high density polyethylene (HDPE) holding chamber. The water then infiltrates through the open-bottomed holding chamber into the native soil and eventually to groundwater. During extremely heavy storm events (greater than 1 inch per hour), excess water is channeled through an overflow PVC pipe.

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