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The National Inventory of Dams (NID) is a congressionally authorized database, which documents dams in the U.S. and its territories. The NID was most recently reauthorized in the Dam Safety Act of 2006. The current NID, published in 2010, includes information on 84,000 dams that are more than 25 feet high, hold more than 50 acre-feet of water, or are considered a significant hazard if they fail. The NID is maintained and published by USACE, in cooperation with the Association of State Dam Safety Officials (ASDSO), the states and territories, and federal dam-regulating agencies. The database contains information about the dam’s location, size, purpose, type, last inspection, regulatory facts, and other technical data. The information contained in the NID is updated approximately every two years.The 2010 NID includes information on approximately 84,000 dams of which 80 percent are regulated by the State Dam Safety Offices and almost 70 percent of the entire inventory is privately-owned dams. The federal government owns only 4% of the total NID, which includes approximately 40% of the tallest dams. From the 2010 NID, 13,990 dams are classified as high hazard potential, 12,662 significant, 57,362 low and 116 undetermined. Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life. Significant hazard potential are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss. Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/ or environmental losses. Losses are principally limited to the owner’s property. This hazard potential classification does not indicate the condition of the dam. There are approximately 2,000 more dams listed as high hazard potential than the previous NID. |