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

从1997年和2001年的红河，到1999年北卡罗来纳州的柏油河，再到1993年、1995年、2001年和2002年的密西西比河，反复发生的洪水使人们断言，人类活动增加了大河洪水的强度和频率。然而，人类洪水强迫的假设仍然未经证实，并且在政治上存在争议，最近国家研究委员会的一个小组得出结论，“有……人类对洪水强度和频率的影响很少被仔细记录下来”。本文提出的研究目的是提供一种经验的、全系统的工具，用于量化人类对密西西比河水系洪水阶段的影响。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。通过对研究河流上长时间测量站的特殊测量仪分析，测量洪水危害的放大程度。具体规格技术量化了相对于基线历史条件的固定流量条件下阶段响应的变化，从而隔离了河流工程和河道改造的局部影响。为了量化潜在的自变量，我们将在研究河流上建立一个过去70-100年的工程结构及其安置和改造历史的GIS数据库。这种数据库是1993年洪水之后机构间洪泛区管理审查的一项主要建议。这个数据库将为这里提出的分析而建立，然后将分发给广泛查阅和使用。目前，美国河流上的地方和区域工程活动正在被审查、授权，其相对成本和效益评估很少或根本没有认识到这些活动可能会提高洪水水位，降低复发时间，或造成未来洪水增加的经济损失。这里提出的研究将提供一种工具，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、规划者和政治家们应该在以下两方面寻求平衡：1)控制洪水和改善航运对当地的好处；2)这些建筑可能造成的洪水风险增加。

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.