Washington's global footprint, particularly since the Sept. 11, 2001, terrorist attacks, U.S. diplomacy, frequently accompanied by military forces, has been greatly expanded in new regions, from North Africa through the Middle East to Central Asia.

One element that these regions share is that these arid regions are all "water stressed," presenting Washington with a new diplomatic conundrum: how to deal equitably with the competing claims of riverine states competing for limited aquatic resources.

As Washington's foreign priorities are primarily military and economic, local economic issues usually are of lesser concern. But a rising issue of local concern in regions where the United States is expanding its presence rarely merits a comment in Washington -- water.

The issue has raised concerns in other international forums, with the United Nations designating March 22 as the first "World Water Day" and 2013 as the "International Year of Water Cooperation."

Water is a finite resource and population increases are increasing pressures on its equitable distribution. One billion people have no access to fresh water and 2 billion lack access to basic sanitation.

Last September during a meeting of 40 former leaders in Oslo, Norway, former Canadian Prime Minister Jean Chretien said the world needs to find the equivalent of the flow of 20 Nile Rivers by 2025 to grow enough food to feed a rising global population and avoid conflicts over water scarcity.

Accordingly, on World Water Day the United Nations issued a first working definition of water security, highlighting sustainable supplies to ensure human well-being, avert water-related disasters, conserve ecosystems and aid economic and social development.

Ten years ago, former U.N. Secretary-General Boutros Boutros-Ghali observed, "Water will be more important than oil this century." Given this rising importance, the possibility of conflict over the precious resource is also rising.

The problem is most acute in transboundary river basins, where a number of countries share a river course. Among the most visible of these are the Nile River basin, which encompasses 11 countries; the Tigris-Euphrates, which originates in Turkey before flowing through Syria and Iraq to join as the Shatt al-Arab before debouching into the Persian Gulf; and the Amu Darya and Syr Darya, which arise in Kyrgyzstan and Tajikistan before flowing westward through Uzbekistan, Kazakhstan and Turkmenistan before reaching the Aral Sea.

Given rising U.S. diplomatic and military presence in Africa, the Middle East and Central Asia, the question for U.S. policymakers then, if whether to favor the interests of a particular nation in one of these contested waterways or seek a regional solution? For in many of these basins, the United States has clear favorites along with those nations with whom it has chillier relations. While Egypt, the last nation the Nile transits, is a U.S. ally, upstream neighbor Sudan is most certainly not. Father east, in the Tigris-Euphrates basin, Turkey is a strong U.S. ally but the same cannot be said of downstream neighbors Syria and Iran.

In Central Asia the United States is on relatively equitable terms with the five "Stans" -- Kyrgyzstan, Tajikistan, Uzbekistan, Kazakhstan and Turkmenistan -- but the United States must be seen to be evenhanded in approaching the sensitive issue of transboundary rivers. The 1,500-mile-long Amu Darya and the 1,380-mile Syr Darya, whose combined flow before massive Soviet agricultural projects were implemented, equaled the Nile.

The rivers together contain more than 90 percent of Central Asia's available water resources but upstream states are interested in building massive hydroelectric projects that the downstream countries fear will lessen water flow. Kyrgyzstan wishes to build the Kambarata hydroelectric cascade, Tajikistan the massive Rogun dam, which downstream Uzbekistan, Kazakhstan and Turkmenistan all fear could damage their agriculture.

It isn't a problem that U.S. diplomacy can ignore forever -- worldwide there are 260 international river basins, covering nearly half of the Earth's surface, along which 40 percent of the world's population lives.

Fortunately for Washington a diplomatic solution exists, should it wish to avail itself of a key piece of U.N. legislation -- the Convention on the Law of the Non-Navigational Uses of International Watercourses, adopted by the U.N. General Assembly in 1997 after 27 years of negotiation, whose Article 5 states, "Watercourse States shall in their respective territories utilize an international watercourse in an equitable and reasonable manner."

Rather than attempt to craft endless bilateral treaties with riverine states, which is certain to cause additional diplomatic stresses in such watercourse basins, the United States should make it an integral element of its foreign policy to urge all disputing states to ratify and adhere to the convention's terms as a basis of negotiations.

And there are indications that Congress is beginning to take an interest in water issues. On March 13 a briefing was convened to look into water resource management issues in Central Asia. It was led by U.S. Rep. Dana Rohrabacher, R-Calif., chairman of the Europe, Eurasia and Emerging Threats Subcommittee of the House of Representatives.

Highlighting the importance in giving Washington an in-depth view of the region's water issues, among those speaking were Uzbek Minister of Foreign Affairs Abdulaziz Kamilov; Uzbek Senate Committee on Foreign Affairs chairman Sadiq Safayev; Deputy Speaker of the Uzbek Legislative Chamber Bori Alihanov and Deputy Minister for Agriculture and Water Shavkat Khamraev.

As the United States downsizes its military footprint in Afghanistan, other regional issues will inevitably arise and if the United States makes supporting the U.N. Convention on the Law of the Non-Navigational Uses of International Watercourses an integral part of its foreign policy, its impartiality will win it friends not only in Central Asia, but throughout the world's arid regions.

Such a policy will still have obstacles -- as if underscoring the intricacies of aquatic issues, the convention has yet to enter into force, as to enter into force, it requires ratification by 35 countries but only 29 have done so. While Uzbekistan has ratified the convention, it is the only Central Asian country to do so.

If the United States wishes to retain its influence in Africa, the Middle East and Central Asia, its policies must be seen to be evenhanded, and given the rising importance of water, ratifying the U.N. convention and then promoting it as a model for negotiation would be a good place to start, as far from raising tensions, the convention can only ease them.

(John C.K. Daly, a former United Press International staff member, is a non-resident Fellow of the Central Asia-Caucasus Institute of the Johns Hopkins University in Washington.)

(United Press International's "Outside View" commentaries are written by outside contributors who specialize in a variety of important issues. The views expressed do not necessarily reflect those of United Press International. In the interests of creating an open forum, original submissions are invited.)