Conceptual Design Framework for Coastal Flood Best Management Practices

Over the past few decades, the development of municipal societies along flood-prone areas such as waterfronts and riverbanks has increased rapidly, causing flood-induced disasters more often than ever before. Flood defense systems have defaulted to gray infrastructure for many centuries. However, more recent storms such as Superstorm Sandy revealed the shortcomings of gray solutions, and therefore the notion of adaptability has been directed to the use of green infrastructure. In flood risk management, nature-based strategies have already proven considerable flood-reducing potential while effectively conserving the ecosystem. However, while nature-based approaches are extremely beneficial in preserving the ecological characteristics of the region, they cannot be solely relied on when it comes to rarely occurring events such as extreme floods. Best management practices (BMPs) are one of the most commonly used safeguards in which natural elements can be integrated into traditional infrastructure designs. In this paper, different strategies are proposed to highlight the immense effects of combining green and gray approaches on both flood mitigation and prevention cost. These strategies focus on flow through vegetation (dense plants), which could be patterned as flow through porous media; and were applied to Westchester Creek, New York. Suggested conceptual designs were then simulated in a hydrologic model. Flood inundation maps generated through the modeling process were then compared in five different scenarios including before and after BMPs. The results of this study showed how the combination of levee and vegetation could significantly lower surge effects while proving to be cost-effective. The methodology outlined in this paper can be used for other urban coastal settings to plan for flood preparedness.