Numerical modeling of aquaculture dissolved waste transport in a coastal embayment
- 342 Downloads
Marine aquaculture is expanding rapidly without reliable quantification of effluents. The present study focuses on understanding the transport of dissolved wastes from aquaculture pens in near-coastal environments using the hydrodynamics code SUNTANS (Stanford Unstructured Nonhydrostatic Terrain-following Adaptive Navier–Stokes Simulator), which employs unstructured grids to compute flows in the coastal ocean at very high resolution. Simulations of a pollutant concentration field (in time and space) as a function of the local environment (bathymetry), flow conditions (tides and wind-induced currents), and the location of the pens were performed to study their effects on the evolution of the waste plume. The presence of the fish farm pens cause partial blockage of the flow, leading to the deceleration of the approaching flow and formation of downstream wakes. Results of both the near-field area (area within 10 to 20 pen diameters of the fish-pen site) as well as far-field behavior of the pollutant field are presented. These detailed results highlight for the first time the importance of the wake vortex dynamics on the evolution of the near-field plume as well as the rotation of the earth on the far-field plume. The results provide an understanding of the impact of aquaculture fish-pens on coastal water quality.
KeywordsEffluent pollution Dispersion Aquaculture Numerical modeling Plume dynamics Coastal engineering
Unable to display preview. Download preview PDF.
- 2.California Fish and Game Code Sec.15008 (2006)Google Scholar
- 3.California Regional Water Quality Control Board, Central Coast Region (2002) Waste Discharge Requirements NPDES General Permit for Discharges from Aquaculture and Aquariums. Order no. R3-2002-0076Google Scholar
- 5.Crimaldi JP, Wiley MB, Koseff JR (2002) The relationship between mean and instantaneous structure in turbulent passive scalar plumes. J Turbul 3(014). http://stacks.iop.org/JoT/3/014
- 6.Delaux S, Stevens CL, Popinet S (2010) High-resolution computational fluid dynamics modelling of suspended shellfish structures. Environ Fluid Mech. doi: 10.1007/s10652-010-9183-y
- 7.Fischer HB, List EJ, Koh RC, Imberger J, Brooks NH (1979) Mixing in inland and coastal waters. Academic Press, San DiegoGoogle Scholar
- 11.Jachec SJ, Fringer OB, Gerritsen MG, Street RL (2006) Numerical simulation of internal tides and the resulting energetics within Monterey Bay and the surrounding area. Geophys Res Lett 33. doi: 10.1029/2006GL026314
- 12.Lau YL, Krishnappan BG (1977) Transverse dispersion in rectangular channels. J Hydraul Eng ASCE 103(10): 1173–1189Google Scholar
- 13.Naylor R (2006) Environmental safeguards for open ocean aquaculture. Natl Acad Sci Issues Sci Technol (Spring) 53–58Google Scholar
- 22.Zhang Z, Fringer OB (2006) A numerical study of nonlinear internal wave generation in the luzon strait. In: Proceedings of the 6th international symposium on stratified flows, pp 300–305Google Scholar