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.

Initial Publication Date: December 7, 2016

Blended

Development of Smart Building for a Rapidly Growing Coastal Community

Objective

The objective of this activity is for you to design effective smart building development in a city that is threatened by sea level rise and storms.

Assignment:

Hazard mitigation utilizing smart building and layered defenses (Coastal planning for an urbanized area surrounding a bay exposed to hurricanes)

Note

Information and data for this assignment are obtained from national and state databases (elevation, census, population, and storm surge) and we utilize Tampa Bay, Florida, USA, and surrounding communities as an example.

A group of cities surrounds 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.

Select your choice of protection or mitigation for the city, knowing that the typical hurricane for this area can produce a storm surge of ~3 meters, and waves that are at least 1 m.

Files

Download the worksheet (Microsoft Word 2007 (.docx) 1.9MB Sep7 16)

Questions

For the following questions use the labeled line and polygon features identified in Figure 9.22. Answer the questions using the worksheet linked above.

Select the preferred area that you would allow the city to expand and develop:

a. More high-value beachfront and barrier-island property

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.

c. Waterfront areas close to existing high-density development.

d. An upland tract close to existing high-density development.
Select from the available choices the location of the perimeter levee or dike to protect the city for this typical storm conditions:

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

b. 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.

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

d. Beach nourishment and dune restoration along barrier islands within Area A.
Assume that the polder in location B is constructed along with the surge barriers along line 2. Locate the high risk areas and explain why you think there is elevated risk.
Assume that development is constructed in location C along with the seawalls along lines 3. Locate the high risk areas and explain why you think there is elevated risk.
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 this city given the new expected 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) assuming the same development/protection strategy from question 4. By how much should the seawall be raised to prevent overtopping?