What Approach works the best for River Restoration?

There are several approaches to restore river environment: one is “Naturnaher Wasserbau” construction method in Europe; another is nature oriented river work in Japan, and similar efforts in Korea. Regarding with river basins, there have been examples such as Mersey River basin in the United Kingdom, where the industrial revolution began.

If you were part of any such project please share the technology you have adopted to clean the river and restore the environment. 

Any idea what approach will fit the River Ganga project the best looking at the biodiversity of the river?