Welcome to my new students in Environmental Science.
As a starter there is an interesting BBC article on the issue of a dam on the Blue Nile River in Ethiopia. The dam is opposed by the downstream users Egypt and Sudan. These two countries claim to have a right to 90% of the Nile's flow. This is an example of what is known as a transboundary water issue. There is a similar problem in SE Asia with respect to the Mekong River.