Rijkswaterstaat is developing policy for the Ijssel river area. The Green Rivers is part of the policymaking process to ensure the safety, prosperity, and sustainability of not only the citizens in the river basin, but in all of The Netherlands and globally as well.
As you may have seen in the news, a recent UN report highlighted how humans have greatly changed nature and are now threatening more and more species to the point of extinction. https://www.un.org/sustainabledevelopment/blog/2019/05/nature-decline-unprecedented-report/
We see a great opportunity for Rijkswaterstaat to tackle two of our most threatening issues together; the room for rivers option can both create space for wildlife and help The Netherlands adapt to climate change in a cost-effective way. The Netherlands, as a highly developed area, already has little natural land for biodiversity to prosper. Luckily, it is also highly skilled in engineering, resource management, and efficient with executing infrastructure projects.