Restoring the sinuosity of artificially straightened stream channels

Abstract

Restoration of Danish stream channels is encouraged by the Watercourse Act of 1982 and has been undertaken partly because of the adverse physical and biological effects caused by artificial straightening. A new technique for restoring morphologic and hydrologic diversity to stream channels has been developed, exemplifying the concept of working with nature rather than against it. This relies on re-creating the former sinuosity, cross-sectional dimensions, slope and substrate of a stream channel. Natural fluvial features are restored to a channel, and becaused slope is decreased stability is probable. In turn, this could be beneficial to the flora and fauna of a watercourse and to aesthetic qualities. The technique was applied succcessfully to a small stream in southern Jutland, Denmark, in 1984/5. Additional methods of bank and bed protection were required to limit subsequent minor adjustments along the new course. Further applications of the technique need to be treated individually because of varying local hydrologic and sedimentologic conditions. On-site supervision during construction and planned maintenance are vital components of restoration.