This drainage system is described as a vertical or horizontal through the bridge curb or the bridge deck at curb line.

• A. Closed Drainage System
• B. Open Drainage System
• C. Through-Curb Drainage
• D. Submerged Drainage

Answer: (B)

Open drainage is about directing runoff through surface channels or gutters that lie on or near the bridge deck and curb, releasing it to the exterior rather than carrying it entirely inside pipes. The description of water entering through openings at the curb line on the deck—whether vertically through the curb or horizontally at the curb line—fits this open, surface-discharge arrangement. It emphasizes that the water is not fully enclosed in a conduit, but is exposed and drained via an open path along the curb. That’s why open drainage is the best fit for the description.