Best Method Study of River Morphology from Satellite Images?

What is the ​best method to ​study river ​morphology (​erosion - ​deposition) for ​a series of ​time? ​ What is the ​best method to ​extract the ​exact river ​shoreline? ​How can I ​use them to ​help me in this ​study? ​ What is ​the best ​index to exact ​the river ​shoreline in ​turbid water? ​