Modelling methods and test cases

Due to the regulatory evolution of AutoDEPOMOD, there are two test sites for the SEPA marine fish-farm modelling tools:

  • Bath and in-feed anti-parasitic chemical treatments
  • Benthic impact due to solid organic wastes (site biomass)

Each requires different site set-up and current meter data, which are available below.

Practitioners who intend to produce license recommendations using the SEPA modelling tools should submit two modelling method reports, one describing the assessment of bath and in-feed anti-parasitic chemical treatments, and another describing the assessment of benthic impact due to solid wastes for the determination of site biomass.  Furthermore, two modelling results reports should be submitted, along with associated model output files, and completed Marine Summary MS-Excel workbooks, as described below.

See also the section containing Guidance on reporting

SEPA requires a CD containing the final method and results reports, the modelling files, and the license recommendation summaries.  If file sizes permit, initial drafts may be submitted by email to ffmodelling@sepa.org.uk.  To allow suggestions and comments on initial drafts to be made in-line by SEPA, it is suggested that reports are submitted as MS-Word documents (2003 format), with 'track changes' enabled.

Bath and in-feed anti-parasitic chemical treatments

The objective of this exercise is to determine EQS compliant license recommendations for the five chemicals commonly used to treat infestations of sea-lice.  Individuals wishing to submit their results should produce a modelling summary report and complete the current data summary in the 'biomass' sheet and the 'chemical' sheet of the Marine Summary MS-Excel workbook.

In addition to the modelling tools, the following site-specific data are required:

Bathymetry:

A simplified planar bathymetry is provided to enable the model grid to be defined for the test site.  These data should be copied into the GRIDGEN sub-directory.

Current data:

Site details:

The in-feed test case information may also be found in appendix 3 to Annex H pdf link (2.08mb) of the 'Fish-farm Manual'.

Benthic impact due to solid organic wastes (site biomass)

The objective of this exercise is to determine a compliant site biomass for the given configuration and environmental conditions.  Individuals wishing to submit their results should produce a modelling summary report and complete the 'biomass' sheet of the Marine Summary MS-Excel workbook.

In addition to the modelling tools, the following site-specific data are required:

Bathymetry:

A simplified planar bathymetry is provided to enable the model grid to be defined for the test site, if you do not have access to suitable data.  These data should be copied into the GRIDGEN sub-directory.

Current data: 

These data are synthetic and do not include a pressure record.  Their spring-neap variation does not correspond to reality, so the intermediate tide records should be identified by inspection of the variation in current speed.  Apply a magnetic variation of 3.5oW

Site details:

Guidance on reporting

The purpose of specifying two reports each ('method' and 'results'), for chemicals and biomass, is to minimise the supporting documentation submitted with each application.  The 'method' report also demonstrates understanding of the processes being modelled, their simulation techniques, and their link to discharge limits; the 'method' report is therefore generic.  Consequently, the 'results' report needs only to:

  • reference the 'method' and the concepts and steps in the process it describes;
  • list the site-specific input data;
  • report the results;
  • assess any features of the modelling that present further environmental risk.

As such, the 'results' report should not introduce or reiterate concepts or processes that are properly part of the 'method' document.

Since some of the background and techniques employed in the biomass modelling are also pre-requisite to the in-feed modelling (e.g. preparation of bathymetric data and current data, and cage configuration), these only need be described in one of the 'method' reports; the description can then be referenced by the other.  Owing to the historical precedence of in-feed modelling, it has been the norm to describe such common techniques in the chemical modelling 'method' report.

In summary, the important features of the two reports are as follows:

Method report:

  • it is not a manual; it does not need to detail the operator's interaction with the modelling software's user interface, i.e. not "create a project", "go to this tab", "press that button", etc.;
  • describe the process that's being modelled (not those that are not) and keep background information brief and pertinent;
  • describe how the model simulates the processes - explain the impact and limitations imposed by any simplifying assumptions;
  • describe the process applied to achieve an optimised discharge limit with respect to environmental protection, i.e. data preparation, model setup, and iteration of discharge scenarios to obtain EQS compliance.

Results report:

  • reference the 'Method';
  • list (tabulate) the values of the input data and identify their sources;
  • tabulate results and present model output plots;
  • discuss impacts, with respect to modelled processes, model limitations, and the specific receiving environment;
  • identify, quantify the impacts of, and, where necessary, mitigate any anomalous results;
  • conclude with license recommendations and a summary of the discussion.

The 'method' reports will represent the practitioner's standard supporting information for license applications made under CAR and will reside on the Public Register; as such they should be in clear and correct English, i.e. they should comply with the standard rules for punctuation, grammar, sentence structure, syntax, etc.  If your English technical-writing skills are rusty, there are many useful guides on the web.

It may be useful to consider the following questions, when reviewing the draft text:

  • do the headings reflect the content of the sections?  Might they better be subdivided, under a different heading?
  • does the text describe the process clearly, succinctly, and in a logical order?
  • is the phrasing open to misinterpretation?
  • would it be understood by someone unfamiliar with the process/tools?
  • can the sense be improved by punctuation, rewording, or restructuring (e.g. 'bullet-pointed' lists)?

Finally, see if you can run the model by following the method.  If, at some point in the future, someone else is asked to undertake modelling, would they understand what to do, and why they were doing it, from reading your method?

Links to some writing skills resources

Some British ones:

Some American ones (well-written American English is better than poorly written British English):