THE UNITED NATIONS concluded another in its continuing series of consciousness-raising sessions on economic development the other day, this one a two-week conference on water in Buenos Aires. As these events go, it was a success. A great deal of information on what is for most of the world a desperate and worsening resource problem was pooled. The poor countries made their usual appeal for a handout, and the rich countries countered with a proposal, which was adopted, for a study. Disputes over rivers and the like spanning national borders were kept within reasonale bounds.

There was only one political intrusion of serious note. The Palestine Liberation Organization, of course, created it. The PLO and its puppets on this issue, the Arab states, at one point crudely harassed an Israeli representative who was speaking and, at another, engineered a walkout on an Israeli expert. The Arabs also rammed through a propagandistic anti-Israel resolution, although, to their substantial ambarrassment, it won barely 50 votes out of 120.

Beyond the ugliness there is a special irony. Israel is a world leader in various aspects of water technology. It has made the desert bloom. There is no group of nations that has more need than the Arabs for precisely the technology and know-how in which the Israelis, living in the same region, are expert. The political need for Arab-Israeli cooperation in this field is also geat.Sen. Charles Mathias, for one, has just proposed a cooperative nuclear-energy project in the Sinai that would provide electricity for, among other things, a sizable desalinization facility. When the Arabs turn their back on Isreali water expertise, they are in a very real sense cutting off their own water.