CGRG Bibliography of Canadian Geomorphology
Author : Biron, P.M.; Carré, D.; and Gaskin, S.J.
Date : 2005.
Title : Assessment of a stream deflector restoration project for fish habitat enhancement in the Nicolet River (QC)
Publication : Annual Meeting of the Canadian Association of Geographer. Tuesday, May 31 to Saturday, to June 4, 2005. University of Western Ontario, London, Ontario.
Instream structures such as stream deflectors are often used to create and/or maintain riffle-pool sequences to enhance fish habitat. There is, however, a lack of field studies examining the impact of these structures on the geomorphology of rivers. The objectives of this research are 1) to assess the impact of a restoration project implemented in 1993 in the Nicolet River (Qc), and 2) to characterize the current flow dynamics and sediment transport around paired deflectors in this river. The field site has been surveyed since 1997, and a series of permanent benchmarks was installed in 1999. Changes in bed topography since 1999 were examined using GIS, and related to discharge measurements. Bedload sediment transport was investigated using particle tracers and sediment traps in 2004. Acoustic Doppler velocimeter measurements, as well as Particle Image Velocimeter (PIV) were used to look at the flow dynamics. Results show that one of the upstream-oriented boulder deflectors implemented in 1997 is still efficiently maintaining a pool downstream, whereas the pool downstream of another (shorter) pair of deflectors is slowly filling up. Although paired deflectors should produce a relatively symmetrical disruption of the flow field, bedload patterns show higher transport rates on the left than on the right bank downstream of the structures.
Bibliography of Canadian Geomorphology