Lesson 10: Coastal Processes
This week's lesson will be our last to focus on a specific geologic hazard
that, unlike several geologic processes we've learned about in recent weeks,
does not pose a threat here in Siskiyou County. Nonetheless, California is a
state defined by its coastline (as at Anacapa Island, right) and even those of us living well inland are affected
by the controversies and costs associated with coastal issues. In addition, coastal erosion and flooding are only likely to loom larger in the coming decades as rising global temperature increases sea level and produces stronger storms.
As with the previous chapters on potentially hazardous geologic processes, this one begins with background information on waves, coastal erosion, longshore transport, and storms and then discusses their implications for humanity. For example, you'll learn how predict where waves will focus most of their erosive energy along a coastline and how we can use this knowledge to build structures or take precautions that will protect lives and property.
As you read through this chapter on coastal processes, it will be helpful to take notes on topics addressed by the learning objectives so that you can keep track of key facts and concepts and recall them more easily when we use them later in the semester. Be sure that you are prepared to meet the learning objectives outlined below before you move on to the quiz at the bottom of the page.Finally, in lieu of a typical exercise this week we will be undertaking our first writing assignment. Your job will be to read and then write an outline of a recent article on geologic hazards from one of three I have selected for the class (see "Outline of Article" below). This is the first of three writing assignments you'll do on this same article (more about the abstracts later), so take your time and be sure that you understand the key conclusions and supporting data in the article you choose well before you start writing your outline.
Weekly Learning Objectives
Upon successful completion of this week's lesson, a student is expected to be able to:
- Outline the factors that play important roles in raising the heights of waves, and estimate the depth at which a wave with a given wavelength will begin to interact with the seafloor.
- Decide whether a wave approaching a given coastline will likely come ashore as a plunging or spilling breaker based on the steepness of the shoreface.
- Predict how waves will refract as they approach a coastline and, as a result, where they will concentrate their erosive energy.
- Calculate the beach budget for a given stretch of coast and decide, based on the result, whether the beach is likely to grow, remain constant in size, or erode.
- Predict the direction of longshore transport caused by waves approaching a coastline and where this transport is likely to deposit and erode sediment around man-made structures such as groins, breakwaters, and jetties.
- Recognize the local conditions that can lead to the formation of rip currents and explain how to survive if caught in one.
- Estimate where the strongest winds and rains will come ashore when a hurricane strikes the coast, and what the probability that such a storm will strike a given stretch of the US Gulf or Atlantic coast during a given number of years (see Figure 11.23.)
- Determine the minimum setback from coastal cliffs it would be appropriate to locate: (a) a permanent structure, and (b) a temporary structure, according to NRC standards if the cliffs are retreating at a given rate annually.
Reading and Browsing Assignment
- Read Chapter 12, focusing on the topics outlined in the learning objectives above.
- For a look at the diversity of California's coastline, browse some of the aerial photographs available online at the California Coastal Records Project.
- To learn more about how hurricanes are tracked and forecast, check out the National Hurricane Center website.
Exercise 10: Outline of Article 1 (Due by 9:00 AM on 24-Oct-2011)
This week's exercise is to complete the first of our three writing assignments. To learn about the assignment read through the pointers below and then click on the "Resources" link on the left side of this page, scroll down, and click on "Outline" under "Writing Assignment" near the bottom of the page. This week we'll be completing steps one and two and you'll be turning in the outline of the article you choose from the first set. (Note that steps 3 and 4 are "grayed out"; we will be working on these in future weeks and you do not need to worry about them now.)
- Your first task is to choose one of the three articles on geologic hazards listed at the bottom of the Writing Assignment page and to read that article carefully. You'll find PDFs of the articles we'll be using under the "Resources" tab on our class' Etudes site; just click on the title, log into Etudes, go to our class tab, and choose "Resources" there. Pick the article that interests you most, download it, and read it carefully.
- After you're finished reading through the article once for an overview, go back, read through it a second time, and write down notes on the article's conclusions and the key observations that the author(s) cite to support these conclusions. Don't hestitate to post a note to the discussion board or contact me by private message if you have questions about an unfamiliar term or idea.
- Next, draft an outline of the article's major conclusions and supporting evidence that follows the format of the "sample outline" linked to the Writing Assignment page. In order to organize your outline imagine that you are telling a friend who hasn't read the article what its three or four key conclusions are and what data or observations are presented to support each of them. You want to do your best to focus on the main points of the article and not get sidetracked by peripheral details.
- Your outline does not need to follow the style of the sample outline exactly (e.g., you don't need to use the same font and bullets), but be sure that it includes: (1) the complete article citation; (2) your "PIN" (last 5 digits of your Etudes user id); and (3) the course name and date at the top. Also, be sure that your text is written in complete sentences (not single words or phrases) and that it is well organized and coherent so that a reader can easily follow the main themes of the article.
- Finally, before you submit your outline you should check out the outline grading rubric that is linked to the Writing Assignment page. It will show you what criteria I will use to evaluate your outline. There is no set length for your outline, but if it's longer than about a page and a half it won't be as helpful when you go to write your abstract. (Abstracts are very short, so the more you can winnow the article's main themes from its peripheral details as you prepare your outline, the less work you'll have to do later). Also, if you print a copy of the article be sure to save that copy so that you'll have it to refer to again in a couple of weeks when you'll be writing the corresponding abstract.
- When you have completed your outline go to the Etudes site for our class, go to Exercise 10 in the Etudes "Assignments, Tasks, and Tests" tool and submit your outline as an attached file. Outlines are due by 9:00 AM next Monday (24-Oct-2011.) I'm asking you to send it as an attachment rather than pasting it into the text box because this will preserve your formatting. You should send it as an MS Word document or, if you write it in another program, as a Word-compatible file. If you have any problems just let me know. I will return your outline with comments and a completed rubric by 7-Nov-2011 in time for you to get started on the second part of the writing assignment.
Quiz 10: Coastal Processes (Due by 9:00 AM on 24-Oct-2011.)
After you feel you have met the learning outcomes outlined above, please complete Quiz 10 in the Etudes "Assignments, Tests, and Surveys" area. There are ten questions, each worth one point. If you can answer all of them correctly it means that you know your way around the basics of coastal processes pretty well and are ready to move on to a more detailed look at water resources next week. Remember, answers will be available for review after 10:00 AM next Tuesday so please look over the results of your quiz and contact me if you have any questions about either content or scoring.