Module 7: Hard Structures and Coastal Modifications through Mimicking Natural Processes
The primary goals of Module 7, Hard Structures and Coastal Modifications through Mimicking Natural Processes, are to explore the mechanics of coastal erosion and the factors that affect erosion rates. Students will learn various classical coastal engineering methods for mitigating coastal hazard risks and be introduced to new alternate options for mitigating coastal hazard risks. Upon completion of the module, the students will be able to:
- Understand coastal erosion through exposure to erosion mechanics, and explain how the interruption of sediment transport is related to downdrift erosion;
- Determine erosion rates along a coastline from sequential Google Earth images;
- Describe the classic methods of armoring shorelines or mitigating erosion and state their disadvantages;
- Explain, compare, and contrast examples of innovative approaches to coastal hazard mitigation and describe some alternatives; and
- Differentiate between soft versus hard mitigation strategies and state problems associated with each.
Context for Use
Description and Teaching Materials
In Module 7 students are exposed to coastal engineering structures and learn both the benefits and drawbacks for each. They are introduced to the coastal cell as a unifying concept, and follow activities and examples of applications that include nourishment or protection using methods that mimic natural processes, rather than those that require structural modification. Materials for this module are located at the student materials link below. Teachers can find documentation of the activities at this location as well as rubrics for students. Rubrics for teachers are compiled under Assessment on this site. Suggestions for teaching and a list of the assessments are found below.
Teaching Notes and Tips
What works best for the module?
- Students should be encouraged to read all the supplemental material and watch the videos supplied. Students who read all of the material and follow the supplemental external links will develop the most complete understanding of concepts. Numerous concepts are embedded in the links that will foster a richer understanding of assessment topics ,and students should be encouraged to investigate these materials.
- Students should be encouraged to read the material in the module before coming to lab. The lab, although straightforward, will challenge quantitative skills coupled with the concepts presented in this module, and builds on concepts gained from earlier in the class when physical processes were discussed.
What students found tough and how we adapted to that.
- Students who did not thoroughly read the text and look at the accompanying external links had the most problems with the module. These students had difficulty identifying the hard structures correctly, and lost marks when completing the quantitative aspects of the formative assessments. As a result, those students received lower marks by 20 percent compared to the rest of the class. A greater emphasis was placed on examining these materials for clarity.
- The module assessments were modified to be more guided and with a clearer direction of where topics of the assessments were embedded in the module text. Additionally some of the assessment questions were scaled down so that students could make more general observations and interpretations.
Reflections on Assignments
Formative Assessment 1: Longshore transport at Ocean City inlet, Maryland
- Those students who understood concepts from Module 3 and the unified coastal cell concept by reading the early content of Module 7 and the supplemental links provided generally did very well, and completed the assessment work with ease. We did not have any students who did poorly in this assessment.
- Some students had some difficulty relating the dominant wave approach when simply viewing at coastal inlets. Emphasis was placed on reiterating how groins can trap sand from an updrift location, and implications resulting from that process.
- Students need to fully understand the infilling of a groin over time with sand from an updrift source to successfully complete this assessment. The spreadsheet is straightforward, but some skill to interpret the results in the graphs is required. Students with Excel skills generally do better in this assessment, as they became quickly familiar with how the results were reported, which helps them complete the assessment correctly and with ease.
Formative Assessment 3: Calculating erosion using Google Earth tools
- Students need to feel very comfortable with Google Earth at this stage of the module in order to effectively complete this assessment. Students need to also have some level of comfort using Excel to carry out the necessary calculations to determine the erosion rates, which requires some level of quantitative skill. All UNO students did very well in this assessment.
Module Summative Assessment: Protection of Ocean Beach, California
- Students need to expand their way of thinking about coastal zone management utilizing previous concepts of morphology from the early modules covering sea-level rise, risk, as well as coastal processes and engineering structures. This is required knowledge to successfully complete the summative assessment. The goal of this assessment is to make students rethink how and why engineering activities that do not account for future risk can have large consequences and considerable re-investment, and higher risk. Students need to consider the entire range of topics in this module (and key early modules) in order to effectively complete the assessment.
- Formative Assessment 1: Longshore transport at Ocean City inlet, MD: Students learn about how coastal erosion works and how it impacts sediment transport.
- Formative Assessment 2: Shoreline change due to the presence of a groin: Students evaluate the impact of hard structures on the evolution of a coastline.
- Formative Assessment 3: Calculating erosion using Google Earth: Students measure short-term and long-term erosion rates using Google Earth, and detect trends in eroding coastlines.
- Summative Assessment: Protection of Ocean Beach: Students analyze the benefits of soft versus hard mitigation strategies.
References and Resources
- Student readings are provided in Student Materials — Module 7: Hard Structures and Coastal Modifications through Mimicking Natural Processes
- What is coastal erosion and when is it a problem?, an article from the Concepts and Science for Coastal Erosion Management (CONSCIENCE) project.