Since the primary users of stormwater infrastructure data are field personnel, and Mobile is meant to provide a way of distributing data to field personnel... in the case of stormwater infrastructure... the direction of flow should be easily interpreted through the available symbology. Currently, I don't see a way to provide symbology that allows for a user to easily interpret the mapped direction of flow for a channel/pipe/pond reach/etc.
Let me suggest that efforts include development of more complex symbology that supports such things as symbolizing direction of a line. Thanks
From the documentation...
ArcGIS Mobile supports simple line symbols, character line symbols, and hash line symbols, but it does not support marker line symbols nor line decorations like arrows on the endpoints of lines, for example.