The only crossing of the River Salve is the temple of Paterdomus, requiring you to go through the whole temple before reaching the bridge.
The River Salve is a barrier between Misthalin and Morytania. According to legend, the river will not allow any evil of Morytania to cross the banks. This however has somehow been broken as discovered in the Darkness of Hallowvale quest.
Panning for artefacts in a branch of this river is a part of The Dig Site quest.