The main objective of the SMaRT-OnlineWDN project is the development of an online security management toolkit for water distribution networks that is based on sensor measurements of water quality as well as water quantity. Pseudo-real time modelling of water quantity and water quality variables is the cornerstone of the project. Existing transport model tools are not adapted for online modelling and ignore some important phenomena that may be dominant when lookingat the network in greater detail with an observation time of several minutes. The aim of this deliverable is to report investigations by the SMaRT-OnlineWDN partners about processes of contaminant mixing a T-junctions and transport in pipes