Floodplain Model Lab

Objectives:

1.  Describe the shape of a riverbed as a major factor in where flooding occurs.

2.  Explain that engineers help people identify and prepare for flooding, including the design of dams, levees and dikes to protect people and property when flooding occurs.

3.  Discuss how human modifications to a river may alter the floodplain of the river.

Materials:

·  2 sheets of cardstock

·  Model house template

·  Tape

·  Scissors

·  Colored pencils

·  Aluminum baking pan with Clay

·  Small board (to support aluminum pan)

·  River bed template

Procedure:

1.  Build a house according to diagram on your paper.

2.  Create a riverbed in the clay, matching your group’s template shape.

3.  Check the shape of the riverbed to make sure that it will create the desired effect as described in the trials below. (Engineers create similar models to explore the possible effects of flooding on people and property)

4.  Make extra model houses (if needed) to represent human-made structures in the floodplain that might be damaged by flooding. You will need at least six houses using the Model House Template and cardstock (or paper)

5.  For each of three trials, you will use two or three new houses and assess flood damage by how much water each house absorbs.

6.  Choose spots in the floodplain where their model houses will stand for each trial by making marks in the clay.

7.  Bring their riverbed (clay-covered baking pan) to the sink and prop one side up with your textbook so it has a slight slope. Place the open end onto the sink.

8.  Place two (or three) of your model houses on the floodplain on the spots marked earlier.

9.  Perform each of the three trials on the floodplains, as described in more detail below.

10.  Make your predictions for each trial before performing each trial. Record your predictions and observations in the data table.

Narrow Section River

Trial 1: Pour a half cup of water slowly through the narrow section riverbed model. Record or discuss observations and remove any damaged houses. This trial shows that with a modest amount of water, it flows through the narrow river section without overflowing the riverbed.

Trial 2: Clean up any excess water. Replace any damaged houses with new ones placed on the same position, as marked on the clay floodplain. Pour one cup of water through the rivers bed quickly. Record or discuss your observations and remove any damaged houses. This trial demonstrates water overflowing at the narrow point of the river when there is an increase in water flow.

Trial 3: Clean up any excess water. Replace any damaged houses with new ones placed on the same position, as marked on the clay. Build clay levees (piece of raised clay or small clay walls) around the narrow portion your observations of what happened this time. This trial shows that the river overflows on the downstream side of the levees.

Large Curve River

Trial 1: Pour a half cup of water slowly through the large curve riverbed model

Record your observations and remove any damaged houses. This trial shows that water can flow through and around the large curve without overflowing the riverbed.

Trial 2: Clean up any excess water in the tub. Replace any damaged houses with new ones placed on the same position, as marked on the clay. Pour one cup of water through the riverbed quickly. Record your observations and remove any damaged houses. By increasing the amount of water, this trial demonstrates water overflowing at the first large curve, flooding the peninsula within (ideally).

Trial 3: Clean up any excess water in the tub. Replace any damaged houses with new ones placed on the same position, as marked on the clay. Build a clay levee (piece of raised clay or small clay wall) at the first curve. Again, pour one cup of water quickly through the river again, as in Trial 2. Record your observations of what happened this time. This trial shows that the river overflows on the downstream side of the levee.

Typical River

Trial 1: Pour a half cup of water slowly through the riverbed model (see Figure 9). Record your observations and remove any damaged houses. This trial shows that water can flow normally through the riverbed, without overflowing the riverbed.

Trial 2: Clean up any excess water in the tub. Replace any damaged houses with new ones placed on the same position, as marked on the clay. Create a small blockage in the curve of their river. Pour the same amount of water through the riverbed as you did in Trial 1. Record your observations and remove any damaged houses. This trial demonstrates what happens when a river is blocked completely and suddenly, such as what happens during a large landslide.

Trial 3: Clean up any excess water in the tub. Replace any damaged houses with new ones placed on the same position, as marked on the clay. Remove the blockage from the river. Next, pour one cup of water through the riverbed quickly. Record your observations of what happened this time. This trial shows that even a cleared riverbed cannot withstand a flash flood.

Procedure (continued):

11.  Once you have completed each trial record all observations. Use table on back of page.

12.  Clean up lab station and return the tray/clay to main lab station.

13.  Have your station check by Ms. Stine. Failure to have station checked will result in -15 points.

14.  Answer conclusion questions.

15.  Complete Lab evaluation.

Collect Data:

Trial # / Prediction: Will the river flood or not? Will the houses be affected? / Observations: What happened? Did the houses collapse? / Sketch: Draw your floodplain, positioning the river in the center of their drawing. Color or draw arrows to indicate where the water will go if a flood occurs
Trial #1
Trial #2
Trial #3

Conclusion:

1.  Which flooding scenario caused more damage to the model houses and the floodplain?

2.  What may dangerous about flooding?

3.  How can human modifications (changes) affect the floodplain?