There is guidance on how to apply blockage matrix as per ARR 2016 guidelines in the latest TUFLOW manual.However, the commands still require blockage factors as "Blockage ARI" and the matrix has ARI as an input column (section 5.12.6 of the TUFLOW manual 2018-03-AD).
I was wondering if there were any plans to fully transition all commands and inputs from ARI to AEP. I believe it would add a bit more consistency to the modelling and will make it easier to reference things to clients as per ARR guidelines.
At the moment, there are several different notations floating around everywhere in the industry.
The blockage assessment tool provided by ARR conducts the assessment in AEP:
The paper used for the matrix (Ollett and Syme (2016)) uses a combination of AEP and ARI:
The ARR guidelines seem to generally use AEP (Book 6, Chapter6):