The courses of the world's rivers in most cases are created by geological and natural factors regardless of political boundaries. Human activities such as dams and diversions have interfered with natural courses of rivers for the benefit of upstream and downstream settlers. As population and human knowledge of water resources exploitation increased, military, diplomatic, and legal actions have marked the history of many transboundary rivers in the form of occupations, treaties, and lawsuits. Some international conflicts include Nicaragua and Costa Rica on the San Juan River; USA and Canada on the Skagit River; USA and Mexico on the Colorado, Tijuana and Rio Grande rivers; Guinea and Mali on River Niger; and China, Cambodia, and Vietnam on the Mekong River. There are no uniform international water agreements on transboundary rivers as each river has unique and complex relations to interests within nations and between nations. As water becomes scarce, conflict on water will increase and controlling water will be part of a survival strategy. There is no water issue that does not include land. New political and military developments will grow out of the need to control the watershed and secure water. The Nile probably stands first with 11 nations and over 443 million people claiming it as theirs. The Nile countries are Burundi, Democratic Republic of Congo, Egypt, Eritrea, Ethiopia, Kenya, Rwanda, South Sudan, Sudan, Tanzania, and Uganda. Fragmentation of countries such as Ethiopia and Eritrea, Sudan and South Sudan, and rising autonomous regions within countries increases the number of claimants to the same water, thereby increasing the difficulty of getting into a water agreement.
