Structural modification of culverts

Effectiveness for Biological Quality Elements

At present very little information exists relating to the ecological effectiveness associated with culvert modification.

Relating to fish passage through culverts, Rajaratnam et al. (1998 - 1991) and Bates (1997) have conducted studies to investigate the effects and possible benefits to ecology and habitats, in particular the hydraulic effects and at road culverts. These studies have resulted in design guideline principles for culvert fish passage. Pinkham (2000) has demonstrated that while in general the effect of culverts on fish passage has a negative impact on local habitats, the structural modification of daylighting has been shown to provide some ecological enhancement in particular with regard to a potential increased connectivity role.

Academic references

Armstrong G.S., Aprahamian M.W., Fewings G.A., Gough P.J., Reader N.A., & Varallo P.V. 2004. Environment Agency Fish Pass Manual: Guidance notes on the Legislation, Selection and Approval of Fish Passes in England and Wales.

Bates, K. (1997). Fish passage at road culverts. In: Fishway design guidelines for Pacific salmon. Working paper 1.6,1/97. Washington Department of Fish & Wildlife. pp11-13 to 11-21.

Pinkham, R (2000) Daylighting: New life for buried streams. Colorado: Rocky Mountain Institute

Rajaratnam, N,  Katopodis, C and Lodewyk, . (1988) Hydraulics of offset baffle culvert fishways Can. J. Civ. Eng. 15(6): 1043–1051

Rajaratnam, N,  Katopodis, C and McWitty, N (1989) Hydraulics of culvert fishways II: slotted-weir culvert fishways Can. J. Civ. Eng.16(3): 375–383

Rajaratnam, N,  Katopodis, C (1990) Hydraulics of culvert fishways III weir baffle culvert fishways. Can. J. Civ. Eng.17(4): 558–568

Rajaratnam, N,  Katopodis, C and Lodewyk, . (1991) Hydraulics of culvert fishways IV: spoiler baffle culvert fishways. Can. J. Civ. Eng.18(1): 76-82