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

Visualizing the Lousiana Coast: Slope Calculation

Calculating slope (example):

Simple calculation:

If a house is located 1 km (1000 m) from the shoreline and is 1 meter above mean sea level, then the slope can be expressed as slope = rise/run = 1/1000 = 0.001 or 0.1%

We can also draw this on graph paper using a scale of:
X axis: 1 square = 10 meters of horizontal distance so 100 squares = 1 km (1000m).
Y axis: 1 square = .2 meters of vertical distance (5 squares = 1 meter)

Calculating the slope of the Louisiana Coastline at Isle de Jean Charles:

You will now use your measurements from Google Earth to calculate the total slope of the coast line. This will enable you to use a model to find projected storm surge levels with different storm strengths.

If you like, you can print out the grid below and use it to plot the slope. Your measured distance from the -10 m point in the Gulf of Mexico to Isle de Jean Charles (Question 5 on the previous page) will plot on the X axis. Choose a scale that fits the grid. 2 squares could represent 1 km.

On the Y axis you will plot the elevation. The lowest elevation will be -10 m and the highest is the elevation above sea level you determined for the levee around Isle de Jean Charles (Question 2 on the previous page).

You will want to draw two "legs" of the slope: One runs from -10 m water depth to the shoreline (Timbalier Island), and the other runs from the shoreline to Isle de Jean Charles.

Note: Your total slope will be determined for the entire distance from the -10 m depth to Isle de Jean Charles.

Use the guidelines above to help you complete the plot, or consult the figure below.