Turbulence Characteristics of Flow in a Spiral Corrugated Culvert Fitted with Sloped- and Slotted-Weir Baffles

Baffles are often used to retrofit culverts to aid in fish passage. The objective of this experimental investigation was to compare the turbulent flow structure inside a full-scale spiral corrugated culvert fitted with sloped- and slotted-weir baffles to available turbulence descriptions for non-baffled culverts. Velocity measurements were taken in a 1.83 m diameter, 12.2 m long corrugated metal culvert fitted with sloped- and slotted-weir baffles using a Sontek Micro-acoustic Doppler velocimeter for flow rates of 0.043, 0.085, 0.113, and 0.198 m³/s and culvert slopes of 1.14, 3.00, and 4.33%. Results showed there were only minor differences in the turbulent flow structure created by each baffle type. The most significant differences included higher lateral turbulent intensities on the edges of the jet created by the slotted-weir baffles, and higher turbulent kinetic energies on the left side of the culvert (looking downstream) caused by the sloped-weir baffles. Downstream from a slotted-weir baffle, a reduced velocity and streamwise turbulent intensity zone was found near the left edge of the flow that was similar to that found in the bare culvert. The sloped-weir baffles produced a less pronounced zone near the right edge of the flow.