Lesson Plan by TB

Flooding After Fire Lesson Plan

Standards:

8^th grade Social Studies:  Standard 2, Geography. 1. Use geographic tools to analyze patterns in human and physical systems

Essential Question:  What is the effect of heavy rain on a forest fire burn area?

Vocabulary: flood, flood zone, hydrophobic soil, forest fire

Materials:  (one of each for each group of 4 students):  meter stick, dishwashing basin, dry and wet sponges, spray bottle, 5 Monopoly houses, small amount of play-dough or modeling clay  to adhere houses

Background:  With the communities of Manitou Springs and Colorado Springs in close proximity to the devastating 2012 Waldo Canyon Fire, the lack of vegetation to absorb water and the creation of hydrophobic soils from the intense heat of the fire has created a new concern of extreme flooding.  As witnessed on June 10, 2013, a heavy intense thunderstorm over the burn scar created a flash flood that created mud slides and closed Highway 24.  Several cars were carried downstream by the force of the water on the highway.  http://gazette.com/video-flash-flood-brings-black-water-down-waldo-burn-scar-sweeps-away-motorists/article/1503346 .  *** Note- several cuss words are heard in the audio of the video in case you plan on playing the video for students.

Procedure: 

Give every group of students one meter stick and ask them if they were standing in a fast moving river, how deep could the water be before they would not be able to remain standing.  After reviewing their answers, share with the students that they could be swept away in flowing water that is only 6 inches high.  Ask them how deep do they think the water would have to be before sweeping away a vehicle?  They might be surprised to learn that water only needs to be 12 inches high before it can sweep a vehicle downstream.  Share with them the flash flood link indicated above, which shows a Gazette videographer trapped in his car as it gets swept away in a flash flood.  Next pass out all of the materials to each group of students.  Attach a dry sponge with masking tape to one side of the basin, and attach the Monopoly houses with a very small amount of modeling clay to the other side of the basin.  Align the houses so that when you tilt the basin up at an angle, the houses are underneath the sponge, in “the flood zone”.  Have the students spray the dry sponge with their spray bottles.  Notice what happens to the houses below the sponge.  They are not affected because the sponge, which is acting like a normal pine forest, is soaking up the water created by the rain.  Next switch the dry sponge for a soaked sponge.  This is representing a burn area where the soil became hydrophobic.  After temperatures of 175-200 degrees Celsius, the soil undergoes a chemical change where it is unable to absorb any water.  Spray the “burn area” again with the spray bottles.  Notice what happens to the houses below.  Have the students research areas which have flooded after a severe burn has occurred.