For the Instructor

These student materials complement the Coastal Processes, Hazards and Society Instructor Materials. If you would like your students to have access to the student materials, we suggest you either point them at the Student Version which omits the framing pages with information designed for faculty (and this box). Or you can download these pages in several formats that you can include in your course website or local Learning Managment System. Learn more about using, modifying, and sharing InTeGrate teaching materials.

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Development of Smart Building for a Rapidly Growing Coastal Community (Tampa Bay, FL)

Objective

The objective of this activity is for you to recommend smart building measures for a city that is threatened by sea level rise and storms.

Background

A group of cities surrounds Tampa Bay, FL, a bay/estuary along a tectonically inactive, trailing margin coastline. The coastline surrounding the bay inlet is composed of sandy beaches and barriers, and elevations range from lowlands near mean sea level to Pleistocene uplands of over 10 m. This coastal region is exposed to tropical storms and hurricanes that can produce storm surges of several meters above mean sea level.

Figure 9.18 shows an orthoimage of the region, and Figure 9.19 shows combined bathymetric and topographic elevations along with contours at 0, 5, and 10 meters.

There is growing demand for new development because the city's population is growing. Figure 9.20 shows the population density in persons/acre for each census tract, highlighting the most densely populated portions of the urban area. Figure 9.21 gives the predicted storm surge elevations for the region that have a 1 percent annual chance of occurrence.

The city must expand with new development to continue growing; however, the new development areas should not create significant risk due to the region's exposure to hurricanes. You are a coastal planner employed by the metropolitan area planning commission, and must come up with a recommended course of action.

Assignment

We will begin by exploring Tampa Bay in Google Earth.

First, navigate to 27Ëš46'08" N; 82Ëš33'04" W and zoom to an eye altitude of ~85 km. You should see a bay and coastline similar to what is shown in Figures 9.18 and 9.19 below.
Explore the area by zooming in on various features of the bay and coastline, paying specific attention to the shaded areas denoted A, B, C, and D in Figure 9.22
Click on some photos in these areas to get a better sense of what they look like from the ground.

Questions

For the following questions use the shaded features identified in Figure 9.22 and that you explored in Google Earth. Answer the questions using the Module 9 Lab Assessment .

Select the preferred area that you would allow the city to expand and develop, and justify why you have chosen this area.

Area A: More high-value beachfront and barrier-island property

Area B: A polder on low-lying backbarrier land. A small levee will be constructed around the area and the water drained to create land for development.

Area C: Waterfront areas close to existing high-density development.

Area D: An upland tract close to existing high-density development.
Given the recommendation you made in Question 1, which smart building option would you use to protect the city from typical storm conditions (see Figure 9.21)? Justify your selection.

1. A combined seawall/tidal barrier along line 1 that blocks flow into the bay. The structure crest elevation would be at +5 m.

2. Movable surge barriers (similar to the Thames tidal barrage and Oosterschelde barrier) along the lines labeled 2. The crest elevation at all structures would be at +3 m.

3. Hard seawalls along certain portions of the bay shoreline (lines labeled 3). The crest elevation of the seawalls would be at +4 m.

4. Beach nourishment and dune restoration along barrier islands within Area A.
The 5th Intergovernmental Panel on Climate Change report predicts global sea level rise of 52-98 cm with continued high greenhouse gas emissions and a rise of 28-61 cm for the most optimistic emissions scenario by the year 2100. Based on these predictions, a reasonable (though possibly conservative) estimate of sea level rise by 2100 is 0.5 m (assuming no local processes adding to or subtacting from this estimate). Re-evaluate the threats to Tampa Bay given the estimated rise in sea level and a 15% rise in both surge level and wave height (due to a possible increase in storm magnitude with climate change). Assume that development is constructed in location C along with the seawalls along line 3. If the present plan is to build seawalls at an elevation of +4 m, by how much should the seawalls be raised to prevent overtopping in 2100? What would the implications be for recreational use of the shoreline if such a seawall were built here? Do you think this would increase or decrease future property values?