Author(s): Alan Cuthbertson; Otto Neshamar; Oyvind Thiem; Peter Davies; Jarle Berntsen
Linked Author(s): Alan J S Cuthbertson, Peter A. Davies
Keywords: No Keywords
Abstract: Results are presented from a series of scaled laboratory experiments designed to model the dumping of graded rock masses into a quiescent fjordic water body via either vertical pipes or inclined tunnel shafts. The main environmental concern with this dumping operation relates to the fate of fine suspended particulates present within the rock grain size distribution (GSD), and their potential release into the wider fjord and impact on both wild and farmed salmon stocks. The laboratory experiments therefore consider the dynamic behavior of the graded rock dumps both within the pipes or tunnels, and the particle-laden plumes generated following their release at the pipe/tunnel exit into the water column. Results indicate that hindered fractional settling and size-segregation are the main physical mechanisms controlling rock mass deposition from vertical pipes, while equivalent dumps into inclined pipes behave as particle-laden gravity currents, with a more efficient release of the dumped rock mass (i. e. over shorter time periods) compared to the vertical pipe arrangement. Sequential single-shot mass dumps are also shown, in both dumping arrangements, to control the wider release of fines through re-entrainment processes. Implications for planned full prototype scale dumping operations in natural fjordic water bodies are considered from these idealized, scaled experiments.
Year: 2024