Collaborative Research: Multivariate Geospatial Modeling of Levee Impacts on Flood Heights, Lower Mississippi River

该项目将测试这样的假设：测量到的密西西比河下游洪水位的增加与堤坝高度和沿着范围的逐渐增加有关。 为了检验这一假设，我们将开发一个地理数据库的堤坝的位置和增长在过去的沿着下密西西比河，经验测试观测到的堤坝扩张和洪水位的增加之间的相关性，并比较这个经验模型的结果与1-D和2-D水力模拟结果。 将对档案堤坝地图和调查进行汇编和数字化，将所有水平和垂直坐标记录到一个共同的基准，并用于在各种空间和时间采样窗口内通过研究区域对堤坝范围和高度的增加进行参数化。 这些指标的堤坝增长将测试显着的相关性，随着时间的推移，洪水位的增加量化的特定规格分析的一系列漫滩流量条件。 最后，四个目标建模达到将使用1-D和2-D模拟，以测试堤坝扩张和水文签名之间的因果关系。 这种方法被设计为堤坝影响的分析，即：定量的，经验的，和系统范围内的。 尽管每年用于防洪基础设施的资金高达11亿美元，但美国洪水造成的经济损失在世纪急剧上升。 越来越多的证据表明，这一增长的很大一部分是由于堤坝扩张和其他河流工程活动造成的洪水物理放大。 本项目将提供一个定量的，经验的，系统的分析防洪堤建设的影响后，洪水响应，重点放在下游密西西比河。 其目的是为防洪和滩区工程的评价提供一个实用的工具。 具体而言，这项研究应该提供一个经验工具，量化的影响，每一个新的增量堤防面积或堤防高度的洪水阶段的反应。 目前，如果没有这样一个系统规模的经验工具，堤坝保护面积和堤坝高度正在大幅增加，导致最近在美国洪泛区建造或计划建造数十亿美元的基础设施。

This project will test the hypothesis that measured increases in flood levels on the Lower Mississippi River are linked to progressive increases in levee heights and extent along the river. In order to test this hypothesis, we will develop a geodatabase of levee emplacement and growth during the past 100-125 years along the Lower Mississippi River, empirically test the correlation between observed levee expansion and increases in flood levels, and compare the results of this empirical model with 1-D and 2-D hydraulic modeling results. Archival levee maps and surveys will be compiled, digitized, all horizontal and vertical coordinates registered to a common datum, and used to parameterize increases in levee extent and heights through the study region over various spatial and temporal sampling windows. These metrics of levee growth will be tested for significant correlations with increases in flood levels over time quantified by specific-gage analysis of a spectrum of overbank flow conditions. Finally, four targeted modeling reaches will be modeled using 1-D and 2-D simulations in order to test the causal links between levee expansion and the hydrological signature. This methodology is designed as an analysis of levee impacts that is: quantitative, empirical, and system-wide. In spite of up to $1.1 billion annually spent on flood-control infrastructure, economic damages from floods in the U.S. have risen dramatically during the 20th century. A growing body of evidence suggests that a significant portion of this increase results from physical magnification of flooding driven by levee expansion and other river engineering activities. This project will provide a quantitative, empirical, and system-wide analysis of the impacts of levee construction upon flood response, focusing upon the Lower Mississippi River. The goal is to provide a practical tool for evaluating flood-control and floodplain projects. Specifically, this research should provide an empirical tool for quantifying the impact of each new increment of levee acreage or levee height on flood-stage response. At present, without such a system-scale, empirical tool, large increases in levee-protected acreage and levee heights are occurring, resulting in billions of dollars of infrastructure recently constructed or planned on U.S. floodplains.