Flood Damage Reduction Projects Research Articles

From disaster to sustainability: breaking the cycle of floods in Houston

The consequences of growing urbanization can be perceived in multiple levels around the globe: overpopulated living conditions, water and air pollution, loss of open space, costly transportation infrastructure, food shortages, fires and floods. The Houston metropolitan area is an example of fast urban growth, with a population increase of more than sixteen percent in seven years, going from 5.8 million people in 2010 to 6.9 million in 2017. By 2045, the robust growth of the region is projected to lead to the addition of approximately five hundred square miles of developed area, including an estimated six million parking spaces, seven hundred eighty million square feet of non-residential uses, and three and a half billion square feet of residential use. The accelerated development, in addition to physical features, geomorphic processes and human activities in the region are believed to have caused Houston to suffer through over fifty devastating floods since its settlement, despite some successful flood damage reduction projects. The present study focused on the potential outcomes of an increased use of green infrastructure in comparable urban areas, and its effects on flooding volume. Results from the research revealed that not only these measures would likely improve the performance of existing urban drainage systems and attenuate flood incidence in the area, but would also promote connectivity between areas otherwise detached or only accessible by car, improving walkability and incentivizing engagement in outdoor activities.

Effects of statistical sampling errors on flood-damage-reduction project evaluation

Risk-based decision making of flood-damage-reduction (FDR) projects evaluate different design alternatives having uncertain inundation-reduction benefits and costs. Uncertainties in FDR projects arise from, but not limited to, natural randomness of hydrologic events, knowledge deficiency in hydrologic models and the parameters, among others. This study investigates how the flood damage estimation is affected by the epistemic uncertainty resulting from using finite flood data in defining flood-frequency relationship and its effects on risk-based decision making. Monte Carlo simulation is applied in the study to simulate the epistemic uncertainty associated with the sampling error of the flood magnitude. The model parameter uncertainty is explicitly considered in the estimation of statistical features of flood damage. A recently developed decision rule on the basis of expected opportunity loss (EOL) is applied to risk-based evaluation of the relative merits of several competing flood mitigation projects. EOL-based decision rule has the advantages of considering decision maker's risk-aversion attitude and incorporating more complete statistical features of project outcomes including their correlations. The influence of the model parameter uncertainty on the project evaluation results is examined through an example FDR project with five design alternatives in which flood magnitude follows a Gumbel distribution.

Developing an agricultural flood loss estimation function (case study: rice)

In recent years, flood control has been replaced by flood management concept in terms of living with flood, making benefit of it, and minimizing its losses. Succeeding in flood management in any region depends on the evaluation of different types of flood losses. Because of providing water resources and suitable arable lands, especially in arid and semiarid countries, floodplains are very important for agricultural activities. These lands are naturally vulnerable to flood; henceforth, determining the degree of protection and acceptable risk in flood damage-reduction projects without agricultural flood loss evaluation could be unrealistic. In this research, effective hydraulic parameters for flood loss estimation were determined and a set of laboratory tests were performed to evaluate the loss of rice, as the main crop in the study region, under different hydraulic conditions. In this regard, flow parameters like depth, velocity, multiplication of depth and velocity, shear stress, the Froude number, and the Reynolds number were employed for different rice growth stages including after transplanting, shooting, clustering, and harvesting. Analyzing the results showed that the Reynolds number, as a dimensionless parameter, is the best one for simulation of flood physical factor-loss function. Statistical analysis revealed that the logarithmic function is the best regression equation fitted to the Reynolds number-loss function. The amount of loss depends on growth stage; therefore, the time of flood occurrence is of vital importance for agricultural loss estimation. In this research, it was realized that the amount of loss is increased in the following order: after transplanting, shooting, harvesting, and clustering.

GIS-based distributed technique for assessing economic loss from flood damage: pre-feasibility study for the Anyang Stream Basin in Korea

Large national budgets are required for flood damage reduction projects, making it critical to ensure that public money used therein be spent efficiently. Accordingly, reliable assessment of flood damage is a critical issue in analysis of the economic aspects of flood damage reduction projects. To this end, this study aims to provide a GIS (geographical information system)-based technique for distributed flood damage assessment. We consider two aspects of flood damage assessment from an engineering and economic perspective, i.e. flood inundation analysis and multi-dimensional flood damage analysis (MD-FDA). To perform this assessment, we used a GIS-based framework and data processing method to assess damages. The proposed methodology was applied to flood control channel projects for flood disaster prevention in the Anyang Stream Basin in Korea and presents detailed GIS data processing and assessment results. Findings from this study may contribute to the improvement of usability of MD-FDA and may provide research directions for integrating economic and engineering factors. This distributed technique will also assist in the decision-making process when evaluating the economic feasibility of flood damage reduction projects for structural and non-structural measures.

USACE Experience in Implementing Risk Analysis for Flood Damage Reduction Projects

USACE Experience in Implementing Risk Analysis for Flood Damage Reduction Projects

Nonstructural Flood Damage Reduction Within the U.S. Army Corps of Engineers

Flood damage reduction basically consists of two approaches: structural and nonstructural. Structural flood damage reduction projects are those that focus on altering the characteristics of the flood, leaving the structures in the floodplain that could be damaged by floods unaltered. Nonstructural flood damage reduction projects are those that focus on altering the characteristics of the structures that could sustain flood damages, leaving the characteristics of the flood unaltered. The U.S. Army Corps of Engineers (Corps) has long been a major force in flood damage reduction within the United States. Corps involvement began in the early part of the 19th century when Congress gave the Corps authority to improve navigation on inland river systems. This involvement continued to evolve during the remainder of the 19th century and the early part of the 20th century. The Flood Control Act of 1917 was the first official legislation that authorized the Corps to have a significant role in flood damage reduction activities across the nation. Subsequent to that time, the Corps has constructed and currently operates 383 major lake and reservoir projects, constructed and maintains over 8,500 miles of levees and dikes, and built hundreds of smaller local flood damage reduction projects that have been turned over to non-federal authorities for operation and maintenance. Historically, most flood damage reduction projects within the Corps have been considered structural, with a rather narrowly defined focus of removing the threat of flooding from existing floodplain development. This rather narrow focus ultimately led to increased flood damages. In many areas the floodplains that sustained less frequent flooding due to Corps projects were actually developed more extensively than they would have been without the flood damage reduction project. However, this began to change in the Corps in the early 1960’s.

Estimating Expected Annual Damage for Levee Retrofits

The U.S. Army Corps of Engineers (USACE) has instituted a new analysis methodology for estimating the expected annual damage (EAD) and resulting economic benefits accruing to proposed flood damage-reduction projects. Although the methodology is new, it still, in effect, uses expected probability to estimate the frequency of flooding and EAD. The National Research Council (NRC) in a review of USACE's study of the American River levees stated that the use of expected probability results in significantly biased estimates of EAD. An alternative damage model to that proposed by NRC is used to show that expected probability leads to an unbiased estimate of EAD. The damage model proposed requires that an unbiased estimate of damage results when applied to many projects. A simulation study demonstrates that EAD estimated with expected probability is unbiased, whereas the NRC's recommended estimator is biased.

Water development projects map

A new map showing major water development projects across the United States has been published by the U.S. Geological Survey (USGS). The map shows the location, size, and ownership of approximately 2800 of the nation's major multipurpose and flood control dams and virtually all of the reservoir storage and flood control capacity of the country. Other features illustrated on the map include U.S. Bureau of Reclamation surface water irrigation projects; watershed protection projects of the U.S. Soil Conservation Service; hydroelectric power facilities, including both federal plants and nonfederal plants leased by the Federal Energy Regulatory Commission; U.S. Army Corps of Engineers navigation and flood damage reduction projects; and the federal systems of wild and scenic rivers. The map also delineates major rivers and the 21 USGS water resources region boundaries so that users of the map can locate development projects with respect to drainage basins.