A body structure includes a generally trough-shaped first structural member having a floor, two opposed side walls having respective top edges, and an open top along a length of the first structural member defining a generally U-shaped cross-section. The first structural member has a first portion with a first flow direction therethrough and a second portion with a second flow direction therethrough different from the first flow direction, the first portion having opposed first and second ends with a first opening in the first end, the second portion having opposed third and fourth ends with a second opening in the fourth end, wherein the second and third ends are in fluid communication with each other. The first portion has a first average depth and the second portion has a deepened portion having a second average depth larger than the first average depth.