Coastal Engineering and Societal Response to Coastal Hazards

Authors: Ioannis Y. Georgiou, Dinah MayGarden and Kevin Hanegan, University of New Orleans

Summary and Overview

This section consists of three modules that introduce students to coastal defenses from marine threats, storms, sea-level rise, climate change, and other risks. The introductory module details the mechanics of coastal erosion, and then continues to introduce standard coastal engineering practices for shoreline stabilization, erosion reduction and mitigation. This classically hard structure approach to mitigation is then contrasted with soft approaches. The students are exposed to soft versus hard dilemmas, and advantages and disadvantages resulting from each mitigation practice. Later in the module, students are introduced to case studies that detail how hazard mitigation or protection from risks was adopted and implemented. The students will learn how to measure shoreline erosion rates using sequential image analysis, use simple analytical tools to examine infilling rates of shoreline which incorporate groins or terminal groins, and transfer that knowledge to other systems with similar issues. The second module in this section details the concept of layered defenses to address risk and hazard vulnerability, and introduces a new concept of managed retreat utilizing the Mississippi River Delta as a case study. The section ends with the last module on smart building, which introduces the students to historic approaches to smart building well before modern cities expanded. We showcase the unsustainable growth of a city without or little consideration of risk or hazard resulting from climate change or sea-level rise, and demonstrate how that yielded catastrophic flooding. We revisit several cities throughout the world where smart building exists or is underway, and we show new approaches to mitigation and flood protection using layered or smart building approaches covering examples that span from the individual household to an entire city.

Strengths of the Section

• Module 7: The module consists of an introduction and detailed explanation of structural, hard shoreline mitigation structures, soft alternative mitigation methods, and it covers case studies where such methods were implanted in part or in full. Case studies cover erosion, layered protection, and smart approaches to shoreline mitigation.
• Module 8: The strength of this module lies in the introduction of the concept of managed retreat, a somewhat new concept that will be especially important in low-lying coastal cities worldwide. The students are introduced to modern systems that account for layered defenses, how this approach reduces risk, and how within one coastal system, a combination of factors can contribute to different risk or exposure. We showcase New Orleans as one of the systems that currently exhibits a layered-defense approach, as well as Delta Works in the Netherlands.
• Module 9: This module introduces students to historic smart building approaches with examples from the Mekong Delta, the New Orleans area, and old communities in the Netherlands. The module emphasizes urban growth patterns of modern cities such as New Orleans, growing with no or little consideration of risks, and little emphasis on vulnerability. With storm impacts from recent examples, and knowledge of flood risks, we then demonstrate modern examples of smart building using case studies and proposed designs from around the world, where risk and hazard, and exposure to, as well as natural processes, are considered in the design.

Context

This section serves as the second three-week core of the semester-long course, Coastal Processes, Hazards and Society. The course focuses on geology, hazards, engineering, and policy; the main foci of this section are on the engineering, policy, and hazards components of the course. Although it is intended for use as a component of the full online or blended course, it could potentially be used on its own as a component of a different course, and its modules can be used individually.

Section Goals

Section 3 explores hard shoreline mitigation strategies and their impacts to coastline erosion, and it introduces alternative mitigation approaches using soft engineering methods and material. The section introduces the concept of layered defenses, their direct benefits ,and how these strategies mitigate risk, and in the last module the concept of smart building or building with nature is explored. In completing this unit students will:

• Develop an understanding of the mechanics of coastal erosion;
• Develop the fundamental geospatial and quantitative skills and concepts needed to assess coastal erosion rates; and
• Learn various classical coastal engineering methods for mitigating coastal hazard risks and be introduced to new alternate options for mitigating coastal hazard risks.

Assessment

Section Outline

• Module 7: Hard Structures and Coastal Modifications through Mimicking Natural Processes
• Module 8: Managed Retreat/Multi-Layered Protection
• Module 9: Smart Building