Happy World Water Day! Today is the 16th annual United Nations-sponsored water awareness day. This year's theme "Sharing Waters Sharing Opportunities" aims to up knowledge about all of the bodies of fresh water (263 by the U.N.'s count) that cross – or create – international borders. These can include the usual suspects, such as rivers and lakes, as well as subterranean aquifers that so many rely on for drinking water. Although H20 covers more than 70 percent of the planet's surface, only about 0.3 percent of surface water is in rivers and lakes, and underground aquifers hold about only another 1.6 percent of the earth's water.

More than half of the world's population lives in river basins shared with other countries, according to the U.N., yet only 16 countries (Finland, Germany, Hungary, Iraq, Jordan, Lebanon, Libyan Arab Jamahiriya, Namibia, Netherlands, Norway, Portugal, Qatar, South Africa, Sweden, Syrian Arab Republic and Uzbekistan) have signed the group's Convention on Non-navigational Uses of International Watercourses (an agreement to ensure countries don't hog or harm shared water resources). Per the U.N.'s decision, the agreement won't be ratified until at least 35 nations are officially on board. But some have argued that the convention, which began in discussions back in 1971, doesn't adequately cover new environmental issues or pose a strong enough legal structure to settle potential conflicts. Negotiating the use and conservation of these waters is nothing new, though. People have been making international water treaties for more than 4,500 years (dating at least back to two Sumerian city-states that quibbled over the Tigris River around 2500 B.C.E.).

Today also marks the final day of the 5th World Water Forum in Istanbul, Turkey, which is organized and run every three years by the World Water Council, an international nonprofit. In preparation for the forum, the U.N. released its third World Water Development report last week. While the analysis found promise in increasing access to clean drinking water, U.N. secretary general Ban Ki-moon, said that the global water "situation is unconscionable… There has been a widespread failure to recognize water's vital role in providing food, energy, sanitation, disaster relief, environmental sustainability and other benefits."

But organizers of World Water Day hope to flood that awareness gap, partly through a host of events, which are happening this week from Anchorage to Australia. But to whom should we be raising our glasses of bubby (spring water, that is)? The Danube and its tributaries, of course, which earns the claim as the most international watershed by dipping into 18 different countries.

Image courtesy of badjonni via Flickr