Groundwater resources could be depleted in the next few decades in dry areas of the world where people use lots of water for drinking and irrigating crops, researchers said Thursday. The research was presented at the fall meeting of the American Geophysical Union in San Francisco. “While many aquifers remain productive, economically exploitable groundwater is already unattainable or will become so in the near future, especially in intensively irrigated areas in the drier regions of the world,” said researcher Inge de Graaf, a hydrologist at the Colorado School of Mines in Golden, Colorado.