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The Ogallala aquifer is a large underground source of water in the High Plains region of the United States. A. The use of the Ogallala for irrigation has allowed the High Plains to become one of the most productive agricultural regions in the United States. B. Given the aquifer's low recharge rate, its use for irrigation is causing water tables to drop and will eventually lead to its depletion. C. Releasing capillary water and introducing drought-resistant crops are less-promising solutions to the water supply crisis than bringing in river water D. The periodic deepening of wells and the use of more-powerful pumps would help increase the natural recharge rate of the Ogallala. E. In Texas, a great deal of attention is being paid to genetic engineering because it is there that the most critical situation exists. F. Several solutions to the upcoming water supply crisis have been proposed, but none of them promises to keep the costs of irrigation low.