Unit 5.2: Designing flood-resilient developments

Mark Abolins, Middle Tennessee State University; Karen Viskupic, Boise State University

Initial Publication Date: September 20, 2024

Summary

Students use data and maps to explore flood hazards and design a community where the risk of flooding is reduced. Geographically, students focus on Houston, TX, and their personal places of interest. Unit 5.2 is based on this InTeGrate unit: Hazards from Flooding from the Interactions between Water, Earth's Surface, and Human Activity module.

Houston, Texas, is a major urban center at the intersection of flood and hurricane hazards and climate change. As such, an examination of flooding in this city provides a great starting point for the exploration of these topics in other locales nationwide. This unit focuses on flooding during Hurricane Harvey in 2017, but hurricanes and tropical storms happen nearly every year along the Gulf Coast. For example, Hurricane Nicholas caused ~$1 billion in damage in 2021 even though it was a relatively weak Category 1 storm. In addition, Houston, Texas, is a major oil refining center and a high volume of goods travel through the Port of Houston. For these reasons, disruptions in the Houston area have a profound impact on a substantial fraction of the U.S. population. The Gulf Coast is also at the forefront of climate change because of sea level rise. To mitigate the effects of sea level rise, major engineering works have been proposed for the Houston area, and this is likely an early indication of the magnitude of projects that will be discussed for other parts of the U.S. coast. At the same time, managed retreat, the relocation of coastal residents to inland locations, is being discussed for residents in the nearby community of Port Arthur, Texas. This, too, is an indicator of what will likely be on the agenda in a growing number of coastal communities.

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Learning Objectives

At the end of Unit 5.2, students will be able to:

1. Interpret hydrologic and meteorological data to draw conclusions regarding the interaction between precipitation, discharge, and flooding

2. Calculate recurrence intervals of major flooding for a river system using stream gage data

3. Define a "100-year flood" and explain why floods of that magnitude can occur in successive years

4. Give reasons for including flood mitigation in community planning. Make specific design proposals to mitigate flooding in the student's area of interest

Context for Use

This is the central part of the surface processes unit and will require up to a week of the course.

Description and Teaching Materials

Teaching Materials:

Pre-class homework (20 min):

The pre-class homework introduces students to the flooding that accompanied 2017 Hurricane Harvey in Houston, TX

  • Prompts: Unit 5.2 prework.docx (Microsoft Word 2007 (.docx) 65kB Aug23 24)
  • The pre-class assignment requires use of these slides: HarveyInHouston.pdf (Acrobat (PDF) 2.3MB Jun30 22)
  • Answer key:

The pre-class homework prompts require written responses. The multiple-choice prompts below could be used for rapid formative assessment at the beginning of class, or they could be included in a summative assessment completed after Unit 5.2 or after all of Unit 5.

In class:

In-Class Activity A: Discharge (20 min)

Students learn about 2017 Hurricane Harvey and apply what they have learned to interpret discharge during 2019

The instructor begins by discussing with the students their responses to the pre-class assignment. The multiple-choice prompts above under "Pre-class homework" could be used for rapid formative assessment.

After discussing the pre-class homework, the instructor should show the slides below to the students, provide the slides to the students, or both. Then students should complete the handout (below) in groups. Note that the students have learned about 2017 Hurricane Harvey, and they are being asked to try to apply what they have learned to 2019 discharge. Finally, the instructor leads a whole-class discussion about responses to the prompts.

At this point, students may not yet have enough information to arrive at correct responses without help. For example, students might think that winter and spring discharge events are also caused by hurricanes and tropical storms. Also, they might identify the fall discharge spike as a hurricane which is close to correct, but the spike actually happened during Tropical Storm Imelda.

Answer key:

In-Class Activity B: Precipitation and discharge (20 min)

Students use precipitation and discharge information to explore the relationship between the two

Recommended instructional procedure.

1) The instructor shows the students slides 1-3 and then asks the students to attempt prompts 1-1 through 1-4 in groups. If students want to dialogue about 1-1 through 1-4 while working in groups, the instructor can use slides 4-7 to aid in the conversation.

2) After students attempt 1-1 through 1-4, the instructor uses slides 1-7 to discuss correct responses with them, and students modify their responses accordingly. Then the instructor asks students to attempt 1-5 and 1-6.

3) After students attempt those, the instructor uses slides 9-12 to discuss correct responses with students, and students modify their responses accordingly.

4) Finally, the instructor asks students to attempt 2-1 and 2-2. After students attempt those, the instructor uses slides 14-17 to discuss correct responses with the students, and students modify their responses accordingly.

  • Student handout: Unit 5.2 In-class Activity B (Microsoft Word 2007 (.docx) 857kB Aug23 24)
  • Instructor slides: Unit 5.2 In-class Activity B Slides (PowerPoint 2007 (.pptx) 4.2MB Aug23 24)
  • Answer key:

Rapid formative assessment

Prompts on the handout require written responses. The multiple-choice prompts and answers below could be used for rapid formative assessment in conjunction with a course response system (e.g., clickers).

In-Class Activity C: Flood recurrence (30 min to 45 min with extended discussion)

Students use stream gage data to estimate the frequency with which floods recur

The instructor uses the slides to introduce the assignment. Then students should work in groups to respond to the prompts.

  • Student handout: Unit 5.2 In-class Activity C (Microsoft Word 2007 (.docx) 85kB Aug23 24)
  • Instructor slides: Unit 5.2 In-class Activity C Slides (PowerPoint 2007 (.pptx) 1.1MB Aug23 24)
  • Answer key:

Prompts on the handout require written responses. The multiple-choice prompts and answers below could be used for rapid formative assessment in conjunction with a course response system (e.g., clickers).

Extended discussion about flood recurrence

The flood frequency analysis indicates that discharge exceeded that of the 500-year flood 3 times on the San Jacinto River, TX, during the 81 years of record. This may lead students to (a) question the validity of the analysis and (b) wonder about changes in the magnitude and frequency of flooding during the last few decades. The instructor would be prudent to prepare to discuss these topics, and the instructor might also consider prompting students to discuss these topics. The following PowerPoint contains both national and Houston, TX-specific graphics to aid in these conversations.

Text description of contents of PowerPoint. For the contiguous U.S. as a whole, the frequency and severity of heavy precipitation events has increased consistently within broad regions. Although annual precipitation increased in the greater Houston, TX area, flooding has increased in some parts of the U.S. and decreased in others. Near Conroe, TX, the magnitude of flooding has increased by amounts that are not statistically significant, and the frequency of flooding has increased on some rivers and decreased on others by amounts that are not statistically significant. The lack of statistical significance underscores the challenging nature of attempts to attribute changes in flooding to climate change.

Optional homework. In the optional assignment below, students are asked to use online sources to create a PowerPoint similar to "Has flooding already changed?" for an area of interest to them. The instructor may need to show students how to copy images on a website and paste them into slides.

In-Class Activity D: Floodplain maps and elevation profiles (15 min)

Students use maps and topographic profiles to analyze the geographic extent of flooding

With help from the instructor and working in groups of 2 or more, students complete the following assignment.

  • Student handout: Unit 5.2 In-class Activity D (Microsoft Word 2007 (.docx) 6MB Aug23 24)
  • Instructor slides: Unit 5.2 In-class Activity D Slides (PowerPoint 2007 (.pptx) 8.1MB Aug23 24)
  • Answers:

Prompts on the handout require written responses. The multiple-choice prompts and answers below could be used for rapid formative assessment in conjunction with a course response system (e.g., clickers).

Homework:

Designing a flood-resilient community (60 min)

Students apply what they learned to describe (a) the frequency of flooding and (b) the geography of flooding in their areas of interest. Using what they learned in Unit 5.1 and 5.2, students (c) design a community in which flood risk is reduced. This activity could be implemented as an in-class activity in a computer lab. See "Teaching Notes and Tips" below for more information.

When assigning the homework, show the students the slides below, and consider making these slides available to students. These slides emphasize engineered flood control works that were not emphasized in Unit 5.1. When completing the homework, students should use what they learned from Unit 5.1, and what they learned from these slides.

  • Homework: Unit 5.2 Homework (Microsoft Word 2007 (.docx) 95kB Aug23 24)
  • Excel spreadsheet: Little Satilla River, GA Discharge (Excel 2007 (.xlsx) 20kB Jan16 24)
  • Instructor slides: Unit 5.2 Homework Slides (PowerPoint 2007 (.pptx) 3.7MB Aug23 24)
  • Answers will vary. This file includes solutions for the Little Satilla River, GA dataset:

Teaching Notes and Tips

Introducing Unit 5.2

Perhaps consider VisionLearning's Hydrologic Cycle text as pre-class reading or supplemental reading.

Unit 5.2 In-Class Activity B: Precipitation and discharge

Annual flow in many U.S. rivers is strongly influenced by the storage of precipitation in snow during the winter and melting of snow during the spring, but these phenomena are not part of the hydrologic cycle on the Texas coast. If teaching about these phenomena is important in your setting, perhaps consider using the original InTeGrate activity by Kyle Gray because these phenomena are evident in the Iowa data used in that activity. The link to the Iowa activity is under "References and Resources" below. Here is a hydrograph for a river in a place where snow falls during the winter and melts during the spring: Unit 5.2 Teaching Tips Slide (PowerPoint 2007 (.pptx) 350kB Aug23 24)

Unit 5.2 In-Class Activity C: Flood recurrence

Calculation of flood recurrence intervals lends itself well to use of a spreadsheet (e.g., Google Sheets or Microsoft Excel), but spreadsheet use would likely make the assignment more challenging for some intro-level students. Also, in-class use of a spreadsheet would require students to have access to computers while in the classroom. For this reason, use of a spreadsheet is not explicitly part of the in-class assignment.

Even though a link to a screen-capture instructional video is embedded in the assignment, students will probably find it challenging to download stream gage data from USGS, and then save the data in a format that can be used in this assignment. If the instructor actually wants students to download stream gage data, the instructor should become familiar with the process prior to assigning this homework. Many students will likely benefit from an in-class demonstration of how to use the USGS stream gage sites. If resources and time permit, perhaps consider leading students through parts (a) and (b) of the homework in-person in a computer lab.

A recommended alternative to having students download data from USGS is to have students use the provided data (table at end of assignment, Excel spreadsheet) for the Little Satilla River, Georgia. Use of the provided data will almost certainly greatly reduce completion time, boost the completion rate, and increase student performance.


Assessment

The pre-class assignment and in-class assignments provide for formative assessment. The multiple-choice and true/false prompts provide for rapid formative assessment in conjunction with a course response system (i.e., clickers).

The homework assignment is the summative assessment.

References and Resources

Egger, A.E. (2017) "The Hydrologic Cycle: Earth Science." Visionlearning, Visionlearning, Inc., 12 Feb. 2017, https://www.visionlearning.com/en/library/Earth-Science/6/The-Hydrologic-Cycle/99

FEMA (2022) FEMA's National Flood Hazard Layer (NFHL) Viewer, https://hazards-fema.maps.arcgis.com/apps/webappviewer/index.html?id=8b0adb51996444d4879338b5529aa9cd

EPA (2023a) Climate Change Indicators, https://www.epa.gov/climate-indicators/climate-change-indicators-river-flooding

EPA (2023b) Climate Indicator Map Viewer, https://experience.arcgis.com/experience/bdd9567a847a4b52abd20253539143df/page/Weather-and-Climate/

Google (2017) "Hurricane Harvey from Above." Google Earth, Google. (Historical imagery of this event is no longer available on-line from this source.)

Gray, K. (2020) "Unit 4: Hazards from Flooding." Interactions between Water, Earth's Surface, and Human Activity, 22 Mar. 2020, https://serc.carleton.edu/integrate/teaching_materials/energy_and_processes/activity_4.html

Harris County (2022) "About." Harris County Flood Control District, Harris County, TX, https://www.hcfcd.org/About/Harris-Countys-Flooding-History/Hurricane-Harvey

Mallakpour, I., & Villarini, G. (2015). The changing nature of flooding across the central United States. Nature Climate Change 5:250–254.

Nyman, M., & St. Clair, T. (2016). A Geometric model to teach nature of science, science practices, and metacognition. Journal of College Science Teaching, 45(5).

Rogers, S, & Hackenburg, D. (2017). CURRENTS: Muddy Waters: Defining the 100-Year Flood. CoastWatch, Spring 2017 issue, https://ncseagrant.ncsu.edu/coastwatch/previous-issues/2017-2/spring-2017/currents-muddy-waters-defining-the-100-year-flood/

USGS (2022) The National Map - Advanced Viewer, https://apps.nationalmap.gov/viewer/

USGS (2022) USGS Current Water Data for the Nation, https://waterdata.usgs.gov/nwis/rt

Watson, K.M., Harwell, G.R., Wallace, D.S., Welborn, T.L., Stengel, V.G., & McDowell, J.S. (2018) Characterization of peak streamflows and flood inundation of selected areas in southeastern Texas and southwestern Louisiana from the August and September 2017 flood resulting from Hurricane Harvey. U.S. Geological Survey Scientific Investigations Report 2018-5070, https://pubs.usgs.gov/publication/sir20185070