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Rajaratnam, N., C. Katopodis and S. Lodewyk (1988). Hydraulics of offset baffle culvert fishways. Canadian Journal of Civil Engineering. 15:1043-1051.

The results of an experimental study are presented for the hydraulics of culverts with offset baffles to pass fish. Using analytical considerations and experimental observations, a flow equation has been developed between the discharge, diameter, depth, and slope for a culvert fishway with the standard offset baffle system. The velocity field at the slot has also been evaluated. Some further experiments were performed to assess the effect of baffle spacing and height on the hydraulics of the culvert fishway. Based on preliminary experimental observations and theoretical considerations, a functional relation has been developed between the dimensionless discharge (Q) and the relative depth (yo/D) for culvert fishways with the offset baffle system. This relation has been evaluated using experimental results on two smooth pipes and one rough pipe. These relations are of the form (Q = C(yo/D) to the n power), where the average dimensionless coefficient (C) and the exponent (n) have been experimentally found to be equal to 12.0 and 2.6, respectively. The velocity profiles at the slot offset system are similar and follow a power law with U and the height of the baffles as the scales. The velocity scale (U) in terms of the square root of (gDSo) has been found to be equal to 12.8(yo/D). The effect of doubling the height and keeping the same spacing of the baffles increases the flow resistance appreciably. Keeping the standard height but reducing the spacing to one-half of the standard spacing also improves upon the performance of the standard baffle system.