The conservation organization American Rivers has released its annual ranking of the 10 most endangered rivers in the nation, and Mississippi’s Big Sunflower has the dubious distinction of topping the list. The waterways on the list are not necessarily the most polluted in the U.S; rather, they face the gravest risks of water shortages and other problems. For example, the Big Sunflower is threatened by a proposal to drain 300 square miles of wetlands to build the world’s largest hydraulic pumping plant. The Klamath River in the Pacific Northwest and the Ipswich River in Massachusetts, respectively numbers two and three on the list, face severe water shortages. “America’s seemingly insatiable demand for fresh water is nearing nature’s limits,” said American Rivers President Rebecca Wodder.