Subsurface fluid conveyance chamber and method

A subsurface fluid conveyance chamber comprising:

• a corrugated outer shell extending along a horizontal axis in a manner defining alternating peak corrugations and valley corrugations, the corrugated outer shell having an arch-shaped cross-section with a pair of opposed lateral end walls formed therein and no floor, wherein the end walls and adjacent peak corrugations define a pair of terminal arches, and wherein except for the pair of terminal arches, each peak corrugation defines a ridge having a top surface and a pair of sidewalls, the top surface extending between the pair of sidewalls;
• and
• a pair of inner walls, each of the pair of inner walls attached to and extending along a separate lateral interior wall of the corrugated outer shell and each of the pair of inner walls extending from a location of attachment to the interior wall to a base of the fluid conveyance chamber in a manner inwardly spaced from the corrugated outer shell to define a plurality of interior chambers, each of the interior chambers at a location within a separate inner valley corresponding to one of the alternating peak corrugations formed in the corrugated outer shell, wherein each of the plurality of interior chambers has an inner wall aperture formed in the inner wall and, except for the pair of terminal arches, each of the plurality of interior chambers includes one of the pair of sidewalls, and each of the pair of sidewalls has a sidewall aperture formed therein, wherein the inner wall apertures are vertically offset from the sidewall apertures, and wherein the sidewall apertures are at a vertical location that is lower than the inner wall apertures.