I have a question concerning "water sharing between two countries that share a common river":

  • What is the country water percentage from which the river flows, is the percentage typically higher than the second country?
  • Is there a clear international law that dictates the percentages and legal rights of both countries?

  • What "should" be the case is discussion. What is is on topic. That's why I am editing your question. Also, it would be helpful for you to identify the question. The actual flow is significant. Dec 15, 2013 at 12:32
  • That said, water allocation is both highly political and very much a concern that experts on policy care about. Dec 15, 2013 at 12:34
  • thank you @AffableGeek, please tell me if it's clear. in lebanon we have a River Called Assi, this river originates from lebanon and passes through Syria. The syrian government said that we only have rights for 20% of the water. Do you think it's fair? and is there an international law that explains what the percentage of water every country should have? not necessary between lebanon and syria but in general.
    – Hani Gotc
    Dec 15, 2013 at 12:47
  • well @AffableGeek is there an international law on water allocation, between countries that share a common river? that's what i am trying to see
    – Hani Gotc
    Dec 15, 2013 at 13:05
  • 1
    I think it's generally decided by treaty. Israel, the PA, and Jordan signed a trilateral water distribution agreement about a week ago. Lebanon likely signed an agreement with Syria stating that only 20% of the Assi goes to Lebanon.
    – Publius
    Dec 16, 2013 at 22:44

1 Answer 1


In most cases the boundary is drawn by treaty, but generally, the official boundary is the mid-point between the edge of the water. Each country will have certain rights delineated by treaty, such as who can fish in the river, and so on. There are notable exceptions, however, such as the Rio Grand, which is the boundary between the U.S. and Mexico, which according to treaty lies wholly within U.S. Territory.

It seems you are actually asking about water rights, however, and there is no established customary law. This is a major point of contention for down stream countries, which have historically relied upon water from a source, which gets dammed by the upstream country. Because there is no general agreement, and there is unlikely to be one, the upstream country has a significant advantage because of possession.

For example, the Colorado River between the U.S. and Mexico does not reach Mexico at all during many times of the year. Mexico doesn't like that, but the U.S. refuses to do anything about it.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .