Channelling has been observed in laboratory and field experiments at various scales. However, it is still an open research issue whether a sparse channel network is likely to be a better model than the fracture network model for representing the flow system in fractured rocks. The present report presents a literature study to bring together information useful for addressing this issue. Several key questions are discussed, namely (a) what are the evidences of channelized flow in fractured rocks with laboratory and field measurements?; (b) what is the relationship between generalized flow dimensions from well test analysis and sparse channel network models?; (c) what is the significance of fracture shapes in hydraulic connectivity?; (d) how the probability of flow channels encountering a deposition hole relates to the characteristics of a sparse channel model?; and (e) are there any specific site studies where sparse channel models have been used to model the flow and transport in fractured rocks? A summary, a general discussion and some suggestions conclude the report.
