Background

The potential accumulation of sedimentation from aquaculture production sites can be an important criterion for selection of new sites. Modeling tools for estimating sedimentation can have significant benefits, not only for site selection, but also for determining optimal site configuration (e.g. number and location of cages). Detailed analysis can also give estimates of the maximal advisable production at a new site, with regard to avoiding an extended fallowing period between production cycles.

Integration of numerical models from various disciplines has been a focus in CREATE, and this project make use of a sedimentation model (DREAM) and an oceanographic model (SINMOD). The activity in 2012 has been a pre-project to test the integration and make simple comparisons between model results and in-situ environmental inspections. The ACE (AquaCulture Engineering) site Tristeinen has been used for the test.

Methods

The DREAM model has been developed by SINTEF, initially for evaluating sedimentation from oil drilling operations. Different configurations and input parameters are required for use in the aquaculture domain, for example multiple outlet points (one per cage is used in the pre-project). Another example is the variation of the feces particle size distribution over time due to fish growth and different feeds used during the production cycle. The SINMOD model delivers detailed 3D current fields over time, in this case using a 32 meter grid to obtain enough details. Accurate seafloor topographical data (Olex) from the site surrounding area were used as input.

Results

The test case setup is shown in the figure below. Alternative 1 is the current site configuration, while alternative 2 has been discussed by site operatives as a possible improvement with respect to sedimentation build-up at the site.