Multivariate Geospatial Analysis of Engineering and Flood Response, Mississippi River System, USA

Pinter0229578从1997年和2001年的红河，到1999年的北卡罗来纳州的焦油河，再到1993年、1995年、2001年的密西西比河，再到2002年，反复发生的洪水导致人们断言，人类活动增加了大河洪水的规模和频率。然而，人类强迫洪水的假说仍然没有得到证实，而且在政治上也存在争议。最近，美国国家研究委员会的一个小组得出结论，“人类对洪水规模和频率的影响几乎没有被仔细记录的案例”。这项研究的目的是为量化人类在密西西比河水系中的洪水强迫提供一个经验性的、系统范围的工具。我们建议使用集合时间序列分析来记录和量化这些联系，这是一种多变量技术，用于测试一个或多个因变量(这里是阶段放大)与具有横截面和时间变异性的自变量之间的相关性。洪水风险的放大将使用研究河流上的长期测站的特定量规分析来测量。比规技术量化了相对于基线历史条件的固定流量条件下的水位响应变化，从而隔离了河流工程和航道改造的局部影响。为了量化潜在的自变量，我们将建立一个关于工程结构及其过去70-100年来在研究河流上的就位和改造历史的地理信息系统数据库。这类数据库是1993年洪灾后机构间洪水平原管理审查的一项主要建议。该数据库将为这里提出的分析建立，然后将分发，以供广泛获取和使用。目前正在对美国河流上的当地和地区性工程活动进行审查、授权，并对其相对成本和收益进行评估，但很少或根本没有认识到这些活动可能会提高洪水水位、减少复发时间或在未来的洪水中造成更大的经济损失。这里提出的研究将提供一个工具，用于对密西西比河或其他类似河流的任何增量工程对洪水水位的影响进行实证评估。工程师、规划者和政治家应该寻求在1)防洪和通航改善带来的当地好处和2)这些建筑可能导致的洪水风险增加之间取得公平的平衡。

Pinter0229578From the Red River in 1997 and 2001, to North Carolina's Tar River in 1999, to the Mississippi River in 1993, 1995, 2001, and again in 2002, recurrent flooding has led to assertions that human activities have increased the magnitude and frequency of large river flooding. The hypothesis of human flood forcing, however, remains unverified and politically controversial, and a recent National Research Council panel concluded that "there are ... few cases where human impacts on flood magnitude and frequency have been carefully documented".The purpose of the research proposed here is to provide an empirical, system-wide tool for quantifying human forcing of flood stages on the Mississippi River system. We propose to document and quantify these connections using a pooled time-series analysis, a multivariate technique for testing the correlation between one or more dependent variables (here, stage magnification) and independent variables that have both cross-sectional and temporal variability. Magnification of flood hazard will be measured using specific-gage analysis of long-duration gaging stations on the study rivers. The specific-gage technique quantifies changes in the stage response to fixed discharge conditions relative to baseline historical conditions, thereby isolating the local effects of river engineering and channel modification. In order to quantify the potential independent variables, we will construct a GIS database of engineering structures and their history of emplacement and modification over the past 70-100 years on the study rivers. A database of this kind was a major recommendation of the Interagency Floodplain Management review following the 1993 flood. This database will be constructed for the analyses proposed here and then will be disseminated for widespread access and use. Local and regional engineering activities on U.S. rivers currently are being reviewed, authorized, and their relative costs and benefits assessed with little or no recognition that these activities may raise flood levels, lower recurrence times, or cause increased economic losses in future floods. The research proposed here would provide a tool for empirical assessment of the impact on flood levels of any incremental engineering addition to the Mississippi or other similar rivers. Engineers, planners, and politicians should seek to reach an equitable balance between 1) the local benefits of flood control and navigation improvements and 2) the elevated flood risk that these structures may cause.