MRGO -密西西比河海湾出口

MRGO -密西西比河海湾出口

密西西比河海湾出口 (MRGO) is a 76-mile long artificial channel that was constructed to provide a shorter navigation route between the Gulf of Mexico and the Port of New Orleans.  1956年由美国国会批准,由美国联邦政府完成.S. 1968年,美国陆军工程兵团, MRGO最初的顶部有650英尺宽,至少36英尺深. More earth was dredged to construct the MRGO than was moved to construct the Panama Canal!

作为经济发展项目提出, MRGO使用少,维护费用高(疏浚), 等.). 在2006年, MRGO cost taxpayers nearly $20,000 for each vessel traveling in the channel. MRGO也付出了高昂的环境代价, which scientists and communities along the MRGO had anticipated before the Corps started construction. 当军团疏浚河道时,他们改造了20,000英亩(31英亩)的土地.从2平方英里的湿地到开阔水域, 让海水从海湾流入内陆, 最终又损失了7个,600英亩(11.8平方英里)的湿地和泻湖栖息地. By 2005, 河道两岸的侵蚀使MRGO的宽度扩大到3英尺,有些地区高达000英尺, 让它靠近飓风防护堤岸. Saltwater moving up the channel also damaged or destroyed freshwater cypress forests of Orleans and St. 伯纳德·帕里什,在庞恰特雷恩湖制造了一片死区. All told, the construction and operation of the channel has impacted more than 618,000 acres (965.6 square miles) of habitat—an area almost three times the size of New York City’s five boroughs.

像下九区这样的社区, 而, 迦勒密特也被立起来, a natural storm buffer of cypress trees and other wetlands helped protect them from hurricanes. The MRGO put those communities at risk by damaging or destroying that protective buffer. 尽管圣路易斯市的海拔比新奥尔良的大部分地区都要高. 伯纳德·帕里什和下九区经历了最深的痛苦, most violent flooding in the New Orleans metro area during Hurricane Katrina. 根据8位专家科学家2009年的一份报告, 这一地区的广泛水浸直接是MRGO造成的. 通过详细的波浪和水动力建模, the scientists showed that waves in Lake Borgne were able to rebuild to 8 to 9 feet high as they crossed the MRGO channel, breaching the earthen levees along the channel while the surge was still rising. The flooding was also worsened by the levee-lined intersection of the MRGO and the Gulf Intracoastal Waterway, which funneled storm surge through the MRGO and into the Industrial Canal—flooding the heart of the city. 在卡特里娜飓风, the fierce surge and waves caused levees and flood walls to collapse and unleashed a wall of water into densely populated communities east of the Industrial Canal.

地图显示MRGO的位置, GIWW, the two closures at the rock dam and the surge barrier as well some of the large neighborhoods affected by the storm surge from Hurricane Katrina.

1958年MRGO的疏浚工作(左, 陆军工程兵团, 美联社), MRGO于1957年动工, notice the dead logged cypress in the background and the dynamite blast in the swamp (middle, 陆军工程兵团, 美联社) and a cartoon depicting the MRGO as a bowling alley that allowed storm surge from Hurricane Katrina to knock New Orleans down like bowling pins, 把它描绘成飓风高速公路(对,

An aerial view of the Lower 9th Ward before Hurricane Katrina (left) and immediately after (right). After the hurricane, most houses in the Lower 9th Ward were flooded causing widespread destruction.


(电子邮件 info@ScienceForOur海岸.org 获取粗体打印文档-无超链接) Following Hurricane Katrina, a group of prominent Louisiana coastal scientists released a 报告详细说明MRGO的影响,并建议关闭MRGO. 在2006年, MRGO必须联合行动, a group of 17 local and national non-governmental and community organizations, 是为了倡导圣. Bernard and Orleans Parishes for the closure of the MRGO and restoration of the ecosystem. Advocacy efforts resulted in the deauthorization of the MRGO and requiring that the channel be closed to navigation. This was accomplished by construction of a 950-foot rock dam across the channel, 沿着La Loutre山脊, 圣. 伯纳德·帕里什为修建海峡而被攻破. 此外, 内港通航运河-博涅湖防波堤 was constructed at the top of the MRGO to provide a second closure and additional protection. 作为授权的一部分,国会要求部队开发一套 MRGO生态系统恢复计划  2012年竣工的.  The plan was influenced by record-setting public input 和宣传 efforts. The plan outlines restoration projects and other activities to repair and restore the MRGO ecosystem.

石坝在底部堵住了MRGO, in line with the Bayou la Loutre Ridge (top) and the surge barrier provided a second closure at the top of the MRGO near New Orleans (bottom). The MRGO can be seen going off into the distance on the picture on the bottom left.


MRGO生态系统恢复, 对保护大新奥尔良地区至关重要, 仍在等待关键项目的资金和实施. 尽管公众强烈支持实施修复计划, no funding has been appropriated to the Corps for further study or construction regarding ecosystem restoration in the MRGO impacted areas. Continuing conflicts between the Corps and the State of Louisiana over the State’s cost-share for restoration make it unlikely that the plan will be implemented in the foreseeable future. Comprehensive restoration of the wetlands impacted by the MRGO is critical to achieving maximum resilience for New Orleans and surrounding communities and must be made a priority.

然而,该部队的恢复计划尚未得到资金, some of the projects or portions of the project proposed in that plan are in the 路易斯安那州的可持续海岸综合规划 以及由国家提出的 恢复 资金(BP石油泄漏罚款). Comprehensive restoration of the MRGO ecosystem is essential to repairing the damage done by the dredging and negligent operation and maintenance of the MRGO channel as well as re-establishing the natural lines of defense that protect the surrounding communities and levee system.

美国.S. 在批准的MRGO生态系统恢复计划中. 沼泽和沼泽的营养和恢复的结合, 海岸线保护, 岭恢复, 建议进行MRGO运河修复和牡蛎礁修复.


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2009 MRGO测深(深度)图


MRGO生态系统恢复计划2012 (USACE)