SGER: Hurricane Katrina and Lessons for Responding and Repairing Catastrophic Levee Failures Applicable to Other Similarly Threatened Areas in the U.S.

雷蒙德B。种子，加州大学伯克利分校“SGER：卡特里娜飓风和教训，为应对和修复灾难性堤防故障适用于其他类似的威胁地区在美国。“技术专家早就预见到飓风引起堤坝灾难性破坏和随后新奥尔良洪水泛滥的可能性。 然而，新奥尔良并不是美国唯一存在这种灾难性灾害的地区，但基本上没有得到解决。 加州也存在着惊人的类似情况，即与脆弱的迷宫般堤坝相关的潜在灾难性地震风险，这些堤坝安全地通过该州广泛的供水系统的关键节点，输送加州三分之二的重要淡水。 萨克拉门托市目前是北美最大的大都市区，但堤坝防洪水平最低。额外的关键堤坝系统在整个密西西比河和俄亥俄州河流域以及查尔斯顿地区和美国其他地区提供防洪保护。从新奥尔良堤坝系统的性能以及为淹没地区进行的紧急修复和抽水中，可以学到至关重要的关键教训。 虽然在紧急修复孤立的断裂方面有相当多的经验，但新奥尔良的灾难是一个前所未有的例子，在这个例子中，军事资产被用来协助紧急修复。 这一事件提供了第一次机会，以定量评估这种行动的价值和影响，而不是更传统的使用驳船倾倒岩石和疏浚填料，或陆上运输和设备，以携带和放置新的填土。 将调查各种堤坝断裂处的冲刷侵蚀程度，并与超大型船载“沙袋”的放置率进行比较。“该小组将调查与承包有关的问题和实地安置材料的困难。 其他因素包括渗水以及紧急修复路段的沉降和沉陷。 匆忙修复的长期性能是问题的一个重要因素，永久性修复将在多大程度上受到非正统应急堤坝“补丁”的影响。“其他将被调查的问题包括风力驱动的波浪侵蚀被淹没堤坝背面的程度，由于部分和波浪驱动的漫顶，以及堤坝配置和波峰和上表面保护细节，以及它们与浪涌驱动水位和风驱动波浪的相互作用，在未破坏堤坝部分造成的侵蚀和损坏程度。另一组将被研究的问题是堤坝的设计和配置，以及他们在这个事件中的整体表现。 许多关键的堤坝并没有倒塌，这些也是重要的教训。 设计基础和决策过程导致了目前的堤防配置也是关键因素，将进行调查，这是至关重要的，以吸收这些经验教训，从工程师和人员谁执行和监督的维修，这些经验教训有效地传递给堤防维修专家，应急规划，和风险评估专家在其他地区。 这些经验教训可以提高速度和效率，因此在规划应对大规模（灾难性）紧急情况方面非常宝贵。该跨学科团队受益于美国土木工程师协会和加州水资源部的协同努力和/或资助。 该小组的成员是多样化的，包括国家认可的堤防专家和在自然灾害领域的杰出经验。对卡特里娜飓风过后新奥尔良地区堤坝性能的调查将为美国大片地区关键防护堤坝系统的未来性能提供重要信息

ABSTRACTRaymond B. Seed, University of California, Berkeley"SGER: Hurricane Katrina and Lessons for Responding and Repairing Catastrophic Levee Failures Applicable to Other Similarly Threatened Areas in the U.S." The potential for hurricane-induced catastrophic failure of the levees and subsequent flooding of New Orleans had long been foreseen by technical experts. However, New Orleans is not the only region in the United States in which this type of catastrophic hazard exists, but goes largely unaddressed. A stunningly similar situation exists in California with regard to potentially catastrophic seismic risk associated with the fragile labyrinth of levees that pass two-thirds of California's vital fresh water safely through the key node in the State's extensive water distribution system. The city of Sacramento is currently the largest metropolitan area with the lowest level of levee flood protection in North America. Additional critical levee systems provide flood protection throughout the Mississippi and Ohio River basins, as well as in the Charleston area, and in other regions of the U.S.There are key lessons of vital importance to be learned from the performance of the New Orleans levee systems, and the emergency repair and pumping to dewater the inundated areas. Although there is considerable experience in the emergency repair of isolated breaks, the New Orleans disaster represents an unprecedented instance in which military assets were made available for assisting in emergency repairs. This event provides the first opportunity to quantitatively assess the value and impact of such operations as opposed to more traditional use of barges to dump rock and dredged fill, or land-borne transport and equipment to carry and place new fill soils. The degree of scour erosion at the various levees breaks will be investigated and compared to placement rates of oversized helicopter-borne "sand bags." The team will investigate issues related to contracting and difficulties in the field placement of material. Additional elements include the seepage as well as settlement and subsidence of the emergency repaired sections. Long term performance of the hurried repairs is an important element of the problem, as is the degree to which permanent repairs will be affected by the presence of the unorthodox emergency levee "patches." Other issues that will be investigated include the degree to which wind driven waves eroded the back faces of the flooded levees, the degree of erosion and damage caused in non-breached levee sections due to partial and wave-driven overtopping, and the levee configurations and crest and upper face protection details, and their interaction with surge-driven water levels and wind-driven waves. Another set of issues that will be studied are the levee designs and configurations, and their overall performances in this event. Many critical levees did not fail, and these represent important lessons as well. The design basis and decision process that led to the current levee configurations are also key elements that will be investigated.It is vital to absorb these lessons from the engineers and personnel who performed and oversaw the repairs, and that these lessons be effectively transmitted to levee repair experts, emergency planners, and risk assessment experts in other regions. These lessons can improve speed and efficiency and thus are invaluable in planning the response to large (catastrophic) emergencies. The interdisciplinary team benefits from the synergistic efforts and/or funding from the American Society of Civil Engineers and the California Department of Water Resources. The team members are diverse and include nationally recognized levee experts and outstanding experience in the field of natural disasters. The investigation of the performance of the New Orleans area levees in the aftermath of the Hurricane Katrina will provide vital information for the future performance of critical protective levee systems throughout large areas of the U.S.