Abstract: An assembly for receiving and diffusing stormwater in underground installations includes a horizontally elongated plastic chamber having an arched cross-sectional shape with an upwardly directed apex having an inlet portal. A sediment-accumulating compartment is positioned below the chamber in vertical alignment with the portal. A rigid riser pipe of circular cylindrical configuration penetrates the portal and extends vertically between a bottom extremity located within the chamber and a top extremity positioned substantially at ground level in association with a grated street-level stormwater receiving structure.

Abstract: A sediment accumulating device for use as an accessory disposed below a groundwater receiving chamber engulfed in granular backfill material has a compartment bounded by sidewall structure elongated upon a vertical axis between upper and lower extremities. The upper extremity is open and has a perimeter disposed in a plane orthogonal to the axis. The bottom extremity is closed. Retaining means protrude radially outward from the sidewall structure for receiving downward gravity force from the granular material.

Abstract: A stormwater receiving assembly for processing stormwater containing suspended particulate matter includes a dispensing chamber and an underlying accumulating accessory. The dispensing chamber is fabricated of thin-walled plastic contoured as a corrugated wall horizontally elongated between inlet and exit ends and having an arched cross-sectional shape with upwardly directed peak and spaced apart parallel lowermost edge extremities defining an open bottom. A circular portal is located in the peak of the chamber. The accumulating accessory has a compartment bounded by sidewall structure elongated upon a vertical axis between upper and lower extremities, and is positioned below the dispensing chamber such that the portal of the dispensing chamber is in centered vertical alignment with the lower extremity of the compartment of the accumulating accessory.

Abstract: A chamber of elongated arch-shaped configuration for receiving and dispersing stormwater underground is provided with side portals which receive horizontally disposed infeed conduits that deliver stormwater to the chamber. The positioning and function of the side portals, in conjunction with other design features of the chamber, cause suspended matter in the stormwater to accumulate at the exit end of the chamber, thereby facilitating clean-out of the chamber.

Abstract: A stormwater receiving assembly for processing stormwater containing suspended particulate matter includes a dispensing chamber and an underlying accumulating accessory. The dispensing chamber is fabricated of thin-walled plastic contoured as a corrugated wall horizontally elongated between inlet and exit ends and having an arched cross-sectional shape with upwardly directed peak and spaced apart parallel lowermost edge extremities defining an open bottom. A circular portal is located in the peak of the chamber. The accumulating accessory has a compartment bounded by sidewall structure elongated upon a vertical axis between upper and lower extremities, and is positioned below the dispensing chamber such that the portal of the dispensing chamber is in centered vertical alignment with the lower extremity of the compartment of the accumulating accessory.

Abstract: An elongated plastic chamber utilized for disposal of stormwater has a corrugated wall structure having successive peaks and valleys. The peaks and valleys are connected by upstream and downstream web panels. A series of apertures is disposed in the upstream web panels. The associated facing downstream web panel is smoothly integrated with the corresponding valley to form a curved surface which is concave with respect to the associated peak and serves to deflect outwardly from the chamber water emergent from the apertures. The effect of the interaction of the apertures with the curved surface is to minimize deposition of sediment within the chamber.

Abstract: A chamber of elongated arch-shaped configuration for receiving and dispersing stormwater underground is provided with side portals which receive horizontally disposed infeed conduits that deliver stormwater to the chamber. The positioning and function of the side portals, in conjunction with other design features of the chamber, cause suspended matter in the stormwater to accumulate at the exit end of the chamber, thereby facilitating clean-out of the chamber.