The determination of a roughness value is simple: just fill in the X, Y values (XY left corner down, XY right corner up) from an area (in this case plant/industry) where the emission takes place and the result is one roughness value.

For generating a roughness value for Safety calculations (Safeti-Nl) there is a programm Roughness_maps (named in the Handleiding Risicoberekeningen Bevi versie 3.3), that is not so user-friendly and which uses much older roughness data.

Also, it is difficult to generate one roughness value, so, the question comes, how to calculate the mean value if there is much variation due to the influence of water nearby the plant/industry (river, harbor).

Therefore, I would like to know if Pre-SRM could potentially be used for Safety calculations e.g. safety calculation of the release of a toxic substance.

Hopefully you can give me more information, e.g. how roughness data are generated in Pre-SRM,

In order to get discussion with RIVM about the use of better roughness data in a well-informed way,

Met vriendelijke groet,

Erik Arnold

Adviseur Ecologie en Externe Veiligheid

afdeling Expertise en Advies