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Lake Peigneur is in the US state of Louisiana north of Delcambre and west of New Iberia, near the northernmost tip of Vermilion Bay. It was a deep freshwater body popular with sportsmen until an unusual man-made disaster on November 20, 1980 changed its structure and the surrounding land.〔(Lake Peigneyr TMDLS for dissolved oxygen and nutrients ) EPA 2002 report〕〔(Lake Peigneur - Oil rig disasters - Offshore Drilling Rig Accidents )〕〔(【引用サイトリンク】title= Lake Peigneur Disaster )〕 ==Drilling disaster== On November 20, 1980, a Texaco oil rig accidentally drilled into the Diamond Crystal Salt Company salt mine under the lake. Because of an incorrect or misinterpreted coordinate reference system (the drillers thought the coordinates were in the Universal Transverse Mercator coordinate system when they were in transverse Mercator projection) the drill bit entered the mine, starting a chain of events which turned the lake from freshwater to salt water, with a deep hole. It is difficult to determine what occurred, as all evidence was destroyed or washed away in the ensuing maelstrom. One explanation is that a miscalculation by Texaco about their location resulted in the drill puncturing the roof of the third level of the mine. This created an opening in the bottom of the lake. The lake then drained into the hole, expanding the size of that hole as the soil and salt were washed into the mine by the rushing water, filling the enormous caverns left by the removal of salt over the years. Another explanation is an underwater stream naturally eroded into the enormous salt plug, inevitably making a sinkhole below the lake, which could have been exacerbated by Diamond Crystal illegally and dangerously mining in certain areas. The resultant whirlpool sucked in the drilling platform, eleven barges, many trees and of the surrounding terrain. So much water drained into those caverns that the flow of the Delcambre Canal that usually empties the lake into Vermilion Bay was reversed, making the canal a temporary inlet. This backflow created, for a few days, the tallest waterfall ever in the state of Louisiana, at , as the lake refilled with salt water from the Delcambre Canal and Vermilion Bay. The water downflowing into the mine caverns displaced air which erupted as compressed air and then later as geysers up through the mineshafts. There were no injuries and no human lives lost. All 55 employees in the mine at the time of the accident were able to escape thanks to well-planned and rehearsed evacuation drills, while the staff of the drilling rig fled the platform before it was sucked down into the new depths of the lake, and Leonce Viator, Jr. (a local fisherman) was able to drive his small boat to the shore and get out. Three dogs were reported killed, however. Days after the disaster, once the water pressure equalized, nine of the eleven sunken barges popped out of the whirlpool and refloated on the lake's surface. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lake Peigneur」の詳細全文を読む スポンサード リンク
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