In August the local gouvernement of turin made the decision to remove the plant Myriophyllum aquaticum from our river with the results that after a few days the weeds regrew. For two weeks I attempted to explain to the local government the benefits of these species brand like exotic plant does'nt exist in our ecosystem. A similar episode happened in the USA years ago, then the gouvernement decided to integrate plant and expanded with other species along the rivers to reduce pollution water based on this studies http://www.ncbi.nlm.nih.gov/pubmed/23500103

http://www.sciencedirect.com/science/article/pii/S0301479713000686.

I suggest to add others  local species with similar functions (willows, bambù, typha) along our river to fight against pollutions and to restrict Myriophyllum aquaticum growing creating a little and useful ecosystem helping polluted water..I m waiting for a response.

Nb Now on the border of the river there is only concrete.